Mailgun
mailgun.com
90Score 90 out of 100/100
142.7 of 159 points.
Missed 16.3 points:
An AI agent's path through Mailgun
- FindCan an agent get in and find what it needs?Weakest step81/100
4 of 5 pass · 1 gap
- ReadCan it read what it finds?94/100
11 of 13 pass · 2 gaps
- ActCan it do something with your product?90/100
9 of 12 pass · 3 gaps
GoalAn agent uses Mailgun
Wider segments are worth more points. The overall adds up every check's points, so it isn't the average of the three parts. 1 check doesn't count here: see why.
Easy to find, read and use.
Mailgun passes 4 of 5 Find checks, 11 of 13 Read checks and 9 of 12 Act checks. The weakest step is Act (Errors have a schema, An agent skill is published). One more fails there, but we'd skip it for now.
The pages marketing owns pass. What's left sits with engineering and product.
- Rank
- 8 of 15 · Email APIs8th of 15 Email APIsOn our 9 Nov 2026 scan
- Checks passed
- 24 of 30 counted
- This scan
From our 9 Nov 2026 scan.
Board results come from one dated scan, so every company is compared on the same day. A live scan reads the site as it is now.
- Details
1 check doesn't count here:
- 1 is about an MCP server whose tools we haven't confirmed yet.
1What to fixPart 1 of 4
5 gaps to fix
Most points for the least effort. Each sits next to the file the best email API on our board shipped, as of 9 Nov 2026. One more check fails with no example to follow yet; it's below the fixes.
All 31 checks24 pass · 6 fail
Find
Read
- ✓Readable without JavaScript (AR-READ-01), Pass12 of 15 pass
- ✓Docs readable without a login (LG-READ-01), PassPass
- ✓Real 404s (AR-READ-02), Pass15 of 15 pass
- ✓llms.txt (AR-READ-07), Pass14 of 15 pass
- ✓llms.txt links work, and it fits (LG-READ-02), PassPass
- ✓Docs pages fit an agent's context (LG-READ-04), PassPass
- ✓Meta description (AR-READ-03), Pass15 of 15 pass
- ✓Code samples say their language (AR-READ-05), Pass13 of 15 pass
- ✓Readable pricing (AR-READ-11), Pass15 of 15 pass
- ✓Structured data (AR-READ-08), Pass13 of 15 pass
- ✓Machine-readable discovery file (AR-READ-06), Pass8 of 15 pass
Act
- –MCP server or CLI (AR-ACT-10), Not countedNot counted
- ✓OpenAPI spec (AR-ACT-02), Pass11 of 15 pass
- ✓npm and PyPI packages (AR-ACT-06), Pass11 of 15 pass
- ✓Auth an agent can follow (proxy) (AR-ACT-01), Pass12 of 15 pass
- ✓Every operation has an operationId (LG-ACT-01), PassPass
- ✓MCP server (AR-ACT-03), Pass14 of 15 pass
- ×Tools for browser agents (AR-ACT-07), Fail0 of 15 pass
- ✓Sign-in an MCP client can use (LG-ACT-04), PassPass
Fix 1: Your pages don't point agents at your llms.txt
Do this: Point agents at your llms.txt from your homepage and docs page: a plain link like <a href="/llms.txt">llms.txt</a> in the footer, or <link rel="llms-txt" href="/llms.txt"> in the <head>.
llms.txt linked from your pages: a link on your pages to your llms.txt, so agents know it's there.
×FailWhat we read on Mailgun (2)
- GEThttps://mailgun.com/HTTP 200homepage: no pointer to llms.txt (redirected to https://www.mailgun.com/)
- GEThttps://documentation.mailgun.com/HTTP 200docs page: no pointer to llms.txt
✓PassFrom Mailtrap, on our email API board, as of 9 Nov 2026
- GEThttps://mailtrap.io/HTTP 200homepage: a Link header to https://mailtrap.io/llms.txt
- GEThttps://mailtrap.io/llms.txtHTTP 200an llms.txt with markdown links
What the leader shippedView their file ↗
1a Link header: https://mailtrap.io/llms.txtWhy it might matter
An agent mostly finds files by following links, so it may never try /llms.txt if your pages don't point to it.
Our call · Worth doing.
A link in your footer or <head>, and agents find your llms.txt without guessing its address.
Our judgement.
How we test this
- We read your homepage and your docs page and look for a pointer to an llms.txt: a link to it, a <link> tag, a Link header with rel="llms-txt" or an X-Llms-Txt header, or a line on the page naming /llms.txt.
- It passes when one points at an llms.txt that answers with markdown links.
- AFDocs checks the same (llms-txt-directive).
1 more fails, with no example yet: Tools for browser agents
Nobody on the board passes our check yet
No email API on our board passes our check on these yet, so there's no example to show.
We didn't find tools for browser agents in your homepage's HTML or inline scripts
Tools for browser agents: tools your web page offers to AI agents that work in a browser (a proposed standard).
It costs a point, but it's only worth building if agents need to operate forms on your site. If they do, a browser agent may find no tools to call and have to click through instead.
Don't do it for the score. It's still a proposed standard, and almost nobody on our boards passes our check, though Bird, Postmark and CrewAI load it from a script our check doesn't read. Build it only if agents need to operate forms on your site. Our judgement.
Show every address our checks read
Where our checks looked
Every address our checks read in our 9 Nov 2026 scan, by host. What each check read, not a recording of a visit, so there's no order.
✓ passes on this address alone× fails: select it to open the fix· also read here
mailgun.com
- /robots.txt200 OK·AI agents allowed, homepage reachable: also read here
- /200 OK·Our scanner gets in: also read here·Readable without JavaScript: also read here✓Meta description: Pass✓Structured data: Pass×Tools for browser agents: Fail
- /leaderfile-check-404404 · expected, it's a probe✓Real 404s: Pass
- /llms.txt404 not found·llms.txt: also read here
- /.well-known/oauth-authorization-server200 OK·Machine-readable discovery file: also read here✓Auth an agent can follow (proxy): Pass✓Sign-in an MCP client can use: Pass
- /.well-known/oauth-protected-resource200 OK·Machine-readable discovery file: also read here
- /.well-known/openid-configuration404 not found·Machine-readable discovery file: also read here
- /.well-known/api-catalog404 not found·Machine-readable discovery file: also read here
- /.well-known/agent-card.json404 not found·Machine-readable discovery file: also read here
- /.well-known/agent-skills/index.json404 not found
documentation.mailgun.com
- /robots.txt404 not found·AI agents allowed, homepage reachable: also read here
- /200 OK·Our scanner gets in: also read here✓Docs page: Pass·Readable without JavaScript: also read here·Docs readable without a login: also read here·Docs pages fit an agent's context: also read here
- /docs/mailgun/quickstart200 OK·Readable without JavaScript: also read here·Docs readable without a login: also read here·Docs pages fit an agent's context: also read here
- /docs/mailgun/sdk/nodejs_sdk200 OK·Readable without JavaScript: also read here·Docs readable without a login: also read here·Docs pages fit an agent's context: also read here·npm and PyPI packages: also read here·Install shown for four languages: also read here
- /docs/mailgun/sdk/python_sdk200 OK·Readable without JavaScript: also read here·Docs readable without a login: also read here·Docs pages fit an agent's context: also read here·npm and PyPI packages: also read here·Install shown for four languages: also read here
- /docs/mailgun/sdk/go_sdk200 OK·Readable without JavaScript: also read here·Docs readable without a login: also read here·Docs pages fit an agent's context: also read here·Install shown for four languages: also read here
- /docs/mailgun/sdk/java_sdk200 OK·Readable without JavaScript: also read here·Docs readable without a login: also read here·Docs pages fit an agent's context: also read here·Install shown for four languages: also read here
- /docs/mailgun/mcp200 OK·Readable without JavaScript: also read here·Docs readable without a login: also read here·Docs pages fit an agent's context: also read here–MCP server or CLI: Not counted✓MCP server: Pass
- /llms.txt200 OK·llms.txt: also read here✓llms.txt links work, and it fits: Pass
- /docs/mailgun/quickstart.md200 OK✓Code samples say their language: Pass
- /_bundle/docs/mailgun/api-reference/send/mailgun.yaml200 OK✓OpenAPI spec: Pass✓Every operation has an operationId: Pass✓Send operation in the spec: Pass
www.mailgun.com
- /sitemap_index.xml200 OK✓Sitemap: Pass
- /pricing/200 OK✓Readable pricing: Pass✓Free tier in emails: Pass
5 checks in red are your fixes. Select one to open it.MCP server or CLI weren't counted.
Want a hand fixing this?
Leave your email and we'll reply about the gaps on mailgun.com. One reply, no newsletter.
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2How it comparesPart 2 of 4
How Mailgun compares
Score after each fix
Mailtrap, the leader, at 99ScoreRank
- Nowscore 90rank 8
- +1 fixscore 94rank =5level with Postmark
- +2 fixesscore 97rank 2past Bird (ex-SparkPost), Resend, Brevo and Postmark
- +3 fixesscore 97rank 2
Full scores and ranks on our 9 Nov 2026 board: our maths, not a forecast.
5 gaps with a real example to follow.
Find, Read and Act against the other 14 email APIs
Out of 100. On each bar, the light mark is their median and the dark one their best.
YouMedianBest
- Find81100100Find: 81, median 100, best 100.
- Read9495100Read: 94, median 95, best 100.
- Act908296Act: 90, median 82, best 96.
0100
Where Mailgun stands
On our board
The 15 email APIs on our board average 88, and the top score is 99.
Neighbours on the board
ScoreVs Mailgun
- Loops92+2
- SendGrid92+2
- Mailgun90
- Mailchimp Transactional88−2
- Mailjet88−2
Loops and SendGrid are 2 ahead. One fix, 94, puts Mailgun past both.
Email APIs, our 9 Nov 2026 board. Our maths, not a forecast.
What Mailgun does well
One more thing: only 6 of the 15 email APIs on our board pass Install shown for four languages. Mailgun does.
The checks Mailgun passes that are rarest among the 15 email APIs on our board.
- ✓Install shown for four languagesEM-01 · 6 of 15 on our board pass this
- ✓Machine-readable discovery fileAR-READ-06 · 8 of 15 on our board pass this
- ✓OpenAPI specAR-ACT-02 · 11 of 15 on our board pass this
Compare Mailgun with rivals
3Every checkPart 3 of 4
What these checks can't tell you
- Whether an agent can sign up and get a key. One registry found 30 of 100 developer tools blocked it.
- Whether coding agents write current code for your API. In our small test, a 96 and a 71 came out the same: what we found.
- Whether your bot protection lets an agent in when a person sends one. Check your CDN settings.
- Whether ChatGPT recommends you. That depends on far more than these files.
- What another scanner would give you. They ask different questions and weigh them differently: why the numbers differ.
All 31 checks
24 pass, 6 fail, 0 couldn't check, 1 not counted. The count on each row is how many of the 15 email APIs on our board pass that check.
Find · 4 of 5 pass · 29 of 36 points
✓PassAI agents allowed, homepage reachableAR-FIND-01checked /; none of the user or search agents is blocked10 of 10 points · 15 of 15 pass
10 of 10 points · Gate, worth 10
- GEThttps://mailgun.com/robots.txtHTTP 200checked /; none of the user or search agents is blocked (redirected to https://www.mailgun.com/robots.txt)
- GEThttps://documentation.mailgun.com/robots.txtHTTP 404no robots.txt, so nothing is disallowed
What our check kept, up to 60 lines or 6 KB
Crawl-delay: 10 # START YOAST BLOCK # --------------------------- User-agent: * Disallow: Sitemap: https://www.mailgun.com/sitemap_index.xml # --------------------------- # END YOAST BLOCKHow we test this:
- We read robots.txt and check it doesn't disallow / for the agents that fetch for a user or find sites for AI search: ChatGPT-User, OAI-SearchBot, Claude-User, Claude-SearchBot, Perplexity-User, PerplexityBot (no robots.txt counts as allowed).
- We show blocks on GPTBot (OpenAI model training), not scored; ClaudeBot (Anthropic model training), not scored; Google-Extended (Gemini training and grounding), not scored in v1; CCBot (Common Crawl's open dataset), not scored: blocking them is the site's own call.
- Whether Google-Extended should be scored is a rubric v2 question, and we'll announce it before changing anything.
- Then we fetch your homepage as LeaderfileBot and check it returns 2xx after redirects, with no challenge page.
✓PassOur scanner gets inLG-FIND-01homepage: a real answer (200); docs page: a real answer (200)10 of 10 points
10 of 10 points · Gate, worth 10
- GEThttps://mailgun.com/HTTP 200homepage: a real answer (200) (redirected to https://www.mailgun.com/)
- GEThttps://documentation.mailgun.com/HTTP 200docs page: a real answer (200)
How we test this:
- We fetch your homepage and your docs page as LeaderfileBot, our own scanner, and check neither answers with a challenge page, or a 401 or 403 that a normal browser gets past.
- One blocked page is a fail; both caps your score at 39.
- Firewalls often let in crawlers they can verify, so ChatGPT or Claude may still get in where our scanner can't.
✓PassDocs pageAR-FIND-02docs page, linked from https://www.mailgun.com/7 of 7 points · 15 of 15 pass
7 of 7 points · High, worth 7
- GEThttps://documentation.mailgun.com/HTTP 200docs page from our board config, linked from https://www.mailgun.com/
How we test this:
- We look for your docs page: the first homepage link to a docs., dev. or developer(s). subdomain of your domain, or to a /docs or /developer(s) path; with none, we try https://docs.<host>/ then https://<host>/docs.
- It passes if that page returns 200.
- Board companies use a docs URL we confirmed by hand.
×Failllms.txt linked from your pagesLG-FIND-02Your pages don't point agents at your llms.txt0 of 7 points
Your pages don't point agents at your llms.txt. An agent mostly finds files by following links, so it may never try /llms.txt if your pages don't point to it.
0 of 7 points · High, worth 7
- GEThttps://mailgun.com/HTTP 200homepage: no pointer to llms.txt (redirected to https://www.mailgun.com/)
- GEThttps://documentation.mailgun.com/HTTP 200docs page: no pointer to llms.txt
How we test this:
- We read your homepage and your docs page and look for a pointer to an llms.txt: a link to it, a <link> tag, a Link header with rel="llms-txt" or an X-Llms-Txt header, or a line on the page naming /llms.txt.
- It passes when one points at an llms.txt that answers with markdown links.
- AFDocs checks the same (llms-txt-directive).
✓PassSitemapAR-FIND-03sitemap listed in robots.txt, <sitemapindex> root2 of 2 points · 15 of 15 pass
2 of 2 points · Low, worth 2
- GEThttps://www.mailgun.com/sitemap_index.xmlHTTP 200sitemap listed in robots.txt, <sitemapindex> root
What our check kept, up to 60 lines or 6 KB
<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="//www.mailgun.com/wp-content/plugins/wordpress-seo/css/main-sitemap.xsl"?> <sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"> <sitemap> <loc>https://www.mailgun.com/page-sitemap.xml</loc> <lastmod>2026-11-04T16:12:30+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/about-sitemap.xml</loc> <lastmod>2026-10-16T21:03:45+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/soed-chapter-sitemap.xml</loc> <lastmod>2026-11-02T23:04:53+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/soed-sitemap.xml</loc> <lastmod>2026-09-22T23:04:43+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/email-impact-chapter-sitemap.xml</loc> <lastmod>2026-09-23T09:07:05+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/email-impact-report-sitemap.xml</loc> <lastmod>2026-09-14T14:08:09+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/solutions-sitemap.xml</loc> <lastmod>2026-10-16T13:08:51+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/products-sitemap.xml</loc> <lastmod>2026-09-14T15:15:24+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/enterprise-sitemap.xml</loc> <lastmod>2026-09-14T14:29:37+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/features-sitemap.xml</loc> <lastmod>2026-09-23T09:07:08+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/industries-sitemap.xml</loc> <lastmod>2026-09-14T14:30:48+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/compare-sitemap.xml</loc> <lastmod>2026-11-03T15:04:19+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/research-sitemap.xml</loc> <lastmod>2026-09-14T15:10:14+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/guides-sitemap.xml</loc> <lastmod>2026-09-14T15:14:53+00:00</lastmod> </sitemap> <sitemap> <loc>https://www.mailgun.com/podcasts-sitemap.xml</loc>How we test this:
- We fetch the Sitemap: URL from robots.txt, else /sitemap.xml, and check it returns 200 with a <urlset> or <sitemapindex> root element.
Read · 11 of 13 pass · 70.4 of 75 points
✓PassReadable without JavaScriptAR-READ-01homepage: 1026 words in the raw HTML; docs page: 164 words in the raw HTML; docs surface: 495 words in the raw HTML; docs surface: 284 words in the raw HTML; docs surface: 325 words in the raw HTML; docs surface: 274 words in the raw HTML; docs surface: 183 words in the raw HTML; docs surface: 1078 words in the raw HTML10 of 10 points · 12 of 15 pass
10 of 10 points · Gate, worth 10
- GEThttps://mailgun.com/HTTP 200homepage: 1026 words in the raw HTML (redirected to https://www.mailgun.com/)
- GEThttps://documentation.mailgun.com/HTTP 200docs page: 164 words in the raw HTML
- GEThttps://documentation.mailgun.com/docs/mailgun/quickstartHTTP 200docs surface: 495 words in the raw HTML
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/nodejs_sdkHTTP 200docs surface: 284 words in the raw HTML
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/python_sdkHTTP 200docs surface: 325 words in the raw HTML
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/go_sdkHTTP 200docs surface: 274 words in the raw HTML
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/java_sdkHTTP 200docs surface: 183 words in the raw HTML
- GEThttps://documentation.mailgun.com/docs/mailgun/mcpHTTP 200docs surface: 1078 words in the raw HTML
How we test this:
- We count the visible words in the raw HTML (no JavaScript run) of your homepage and your docs page, and check each has at least 150.
- With no docs page found (AR-FIND-02), the homepage is judged alone.
✓PassDocs readable without a loginLG-READ-01docs page: readable without a login; docs surface: readable without a login10 of 10 points
10 of 10 points · Gate, worth 10
- GEThttps://documentation.mailgun.com/HTTP 200docs page: readable without a login
- GEThttps://documentation.mailgun.com/docs/mailgun/quickstartHTTP 200docs surface: readable without a login
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/nodejs_sdkHTTP 200docs surface: readable without a login
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/python_sdkHTTP 200docs surface: readable without a login
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/go_sdkHTTP 200docs surface: readable without a login
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/java_sdkHTTP 200docs surface: readable without a login
- GEThttps://documentation.mailgun.com/docs/mailgun/mcpHTTP 200docs surface: readable without a login
How we test this:
- We read your docs page and up to 7 more docs pages (the ones we read for other checks, then links on your docs page).
- A page fails when it answers 401 or 403 to a normal browser too, redirects to a sign-in page, or is a sign-in form with little else on it.
- A redirect counts as a sign-in when it adds one: a sign-in path the page didn't have, a login subdomain, or an identity provider's site such as Okta's when the page was on another site.
- A sign-up page, one whose title or main heading says sign up or create an account, isn't a login.
- A refusal only to automated readers is our scanner being blocked, not a login.
- A login on your docs page caps your score at 39; across the pages, a share of 25% or less caps it at 39, 50% or less at 59.
✓PassReal 404sAR-READ-02returned 404 for a page that doesn't exist10 of 10 points · 15 of 15 pass
10 of 10 points · Must, worth 10
- GEThttps://mailgun.com/leaderfile-check-404HTTP 404returned 404 for a page that doesn't exist (redirected to https://www.mailgun.com/leaderfile-check-404/)
How we test this:
- We fetch /leaderfile-check-404, a page that shouldn't exist, and check it returns 404 or 410 after redirects.
- Off the board, if that address refuses automated readers, we try /leaderfile-check-404.html.
✓Passllms.txtAR-READ-07text file with markdown links7 of 7 points · 14 of 15 pass
7 of 7 points · High, worth 7
- GEThttps://mailgun.com/llms.txtHTTP 404returned 404 (redirected to https://www.mailgun.com/llms.txt)
- GEThttps://documentation.mailgun.com/llms.txtHTTP 200text file with markdown links
What our check kept, up to 60 lines or 6 KB
# Mailgun Documentation > LLMS.txt containing a map of all the documentation files for Mailgun. ## Mailgun Send Documentation All of the Mailgun Send documentation. - [Mailgun MCP Server](https://documentation.mailgun.com/docs/mailgun/mcp.md) - [Getting started Sending Email](https://documentation.mailgun.com/docs/mailgun/get-started.md): Getting Started with Mailgun Send - [Quickstart guide](https://documentation.mailgun.com/docs/mailgun/quickstart.md): Quickly get started with Mailgun Send - [Overview | Mailgun API | Sinch](https://documentation.mailgun.com/docs/mailgun/api-reference/api-overview.md): The Mailgun API enables you to send, track, and receive email effortlessly. - [Developer Tools| Mailgun API | Sinch](https://documentation.mailgun.com/docs/mailgun/api-reference/developer-tools.md): The Mailgun API enables you to send, track, and receive email effortlessly. - [Integrations Overview](https://documentation.mailgun.com/docs/mailgun/api-reference/integrations-overview.md): An overview of the tools available to seamlessly integrate with our email products, enabling automation, data synchronization, and enhanced functionality. - [Best practices - Lower Bounce Rates](https://documentation.mailgun.com/docs/mailgun/api-reference/lower-bounce-rate.md): Best practices on how to lower your bounce rate - [Mailbox API](https://documentation.mailgun.com/docs/mailgun/api-reference/mailboxes.md): Mailgun Mailbox API allows you to programmatically create as many mailboxes as you wish - [Authentication | Mailgun API | Sinch](https://documentation.mailgun.com/docs/mailgun/api-reference/mg-auth.md): The Mailgun API enables you to send, track, and receive email effortlessly. - [Razor Error Codes](https://documentation.mailgun.com/docs/mailgun/api-reference/razor.md): Razor is Mailgun's reputation system for detecting spammers and phishers as well as improving deliverability for legitimate customers. - [Golang SDK Reference](https://documentation.mailgun.com/docs/mailgun/sdk/go_sdk.md): Get started with Go on Mailgun - [Introduction SDK reference](https://documentation.mailgun.com/docs/mailgun/sdk/introduction.md): Get started with SDKs on Mailgun - [Java SDK Reference](https://documentation.mailgun.com/docs/mailgun/sdk/java_sdk.md): Get started with Java on Mailgun - [Node.js SDK Reference](https://documentation.mailgun.com/docs/mailgun/sdk/nodejs_sdk.md): Get started with Node.js on Mailgun - [PHP SDK Reference](https://documentation.mailgun.com/docs/mailgun/sdk/php_sdk.md): Get started with PHP on Mailgun - [Python SDK Reference](https://documentation.mailgun.com/docs/mailgun/sdk/python_sdk.md): Get started with Python on Mailgun - [Ruby SDK Reference](https://documentation.mailgun.com/docs/mailgun/sdk/ruby_sdk.md): Get started with Ruby on Mailgun - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/auth_bestpractice.md): Best practices for Authentication - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/bounce_esp.md): Best Practices for Bounce and ESP Feedback Handling - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/dns.md): Best Practices for DNS - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/feedbackloops.md): Best Practices for Feedback Loops and Spam Complains - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/hosting.md): Best Practices for Hosting - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/ip_address.md): Best Practices for Reputation - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/mailinglists.md): Best Practices for Mailing Lists. - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/recipient_eng.md): Best Practices for Recipient Engagement - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/reputation.md): Best Practices for Reputation - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/unsubscribe.md): Best Practices for Unsubscribe Handling - [Best Paractices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/best_practices.md): Best Practices for managing your reputation - [Best Practices](https://documentation.mailgun.com/docs/mailgun/email-best-practices/email_content.md): Best Practices for Email Content - [FAQ](https://documentation.mailgun.com/docs/mailgun/faq/deliver-rep.md): FAQ about deliverability and reputation - [FAQ](https://documentation.mailgun.com/docs/mailgun/faq/faqs.md): Getting started with Mailgun FAQs - [FAQ](https://documentation.mailgun.com/docs/mailgun/faq/receiving.md): FAQ about receiving email for Mailgun. - [FAQ](https://documentation.mailgun.com/docs/mailgun/faq/sending.md): Sending Email FAQs - [FAQ](https://documentation.mailgun.com/docs/mailgun/faq/tracking.md): Tracking Email Messages FAQ - [Mailgun Release Notes](https://documentation.mailgun.com/docs/mailgun/release/release-notes.md) - [Mailgun User Manual Introduction](https://documentation.mailgun.com/docs/mailgun/user-manual/intro.md): Mailgun's User Manual is your complete guide to our email platform, with step-by-step instructions and examples for setup, sending, receiving, and tracking emails using our APIs and web interface. - [GitHub Actions](https://documentation.mailgun.com/docs/mailgun/api-reference/ai-dev/github-actions.md): GitHub Actions integration with Mailgun - [Loveable](https://documentation.mailgun.com/docs/mailgun/api-reference/ai-dev/lovable.md): Loveable integration with Mailgun - [Replit](https://documentation.mailgun.com/docs/mailgun/api-reference/ai-dev/replit.md): Replit integration with Mailgun - [Supabase](https://documentation.mailgun.com/docs/mailgun/api-reference/ai-dev/supabase.md): Supabase integration with Mailgun - [Datadog](https://documentation.mailgun.com/docs/mailgun/api-reference/analytics/datadog.md): Datadog integHow we test this:
- We read llms.txt at your site root and, if your docs live on another host, at your docs root, and check one returns 200, isn't HTML and has at least one markdown link.
- Off the board, we also try your docs. host and /docs/llms.txt.
- We read the first 2 MB: a larger file is judged on that part, and the result says "read the first 2 MB; the file is larger".
✓Passllms.txt links work, and it fitsLG-READ-0232,845 characters, 143 links; 12 of 12 we tried resolve7 of 7 points
7 of 7 points · High, worth 7
- GEThttps://documentation.mailgun.com/llms.txtHTTP 20032,845 characters, 143 links; 12 of 12 we tried resolve
How we test this:
- We read the llms.txt AR-READ-07 passes on (the first with markdown links) and fetch up to 12 of its links, spread through the file, two at a time.
- A link is broken when it answers 404 or 410, or its host doesn't exist.
- A 2xx after redirects resolves, and so does an answer like 400, 405 or 406 that shows the address is there (an MCP endpoint answers a plain GET with 405).
- A refusal, a 429 or a server error isn't judged.
- The credit is the share that resolve, halved when the file runs to 50,000 characters or more, and nothing past 100,000: AFDocs' size bands.
- With no llms.txt it isn't counted: AR-READ-07 counts that.
✓PassDocs pages fit an agent's contextLG-READ-04docs page: 1,164 characters of text; docs surface: 3,286 characters of text; docs surface: 2,124 characters of text; docs surface: 2,356 characters of text; docs surface: 2,135 characters of text; docs surface: 1,396 characters of text; docs surface: 7,604 characters of text7 of 7 points
7 of 7 points · High, worth 7
- GEThttps://documentation.mailgun.com/HTTP 200docs page: 1,164 characters of text
- GEThttps://documentation.mailgun.com/docs/mailgun/quickstartHTTP 200docs surface: 3,286 characters of text
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/nodejs_sdkHTTP 200docs surface: 2,124 characters of text
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/python_sdkHTTP 200docs surface: 2,356 characters of text
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/go_sdkHTTP 200docs surface: 2,135 characters of text
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/java_sdkHTTP 200docs surface: 1,396 characters of text
- GEThttps://documentation.mailgun.com/docs/mailgun/mcpHTTP 200docs surface: 7,604 characters of text
How we test this:
- On each docs page we read (up to 7) we count the characters of visible text in the raw HTML, and of its Markdown copy if it has one, and judge the page by the larger of the two: an agent reading either may be cut off.
- Under 50,000 passes, up to 100,000 is half, more fails: AFDocs' bands, from the limits agents cut pages at.
- The credit is the average across the pages.
✓PassMeta descriptionAR-READ-03has a meta description4 of 4 points · 15 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://mailgun.com/HTTP 200has a meta description (redirected to https://www.mailgun.com/)
What our check kept, up to 60 lines or 6 KB
<meta name="description" content="Powerful Transactional Email APIs that enable you to send, receive, and track emails, built with developers in mind. Learn more today!" />How we test this:
- We check your homepage's raw HTML (no JavaScript run) has a non-empty meta description or og:description.
×FailStructured docs pageAR-READ-04· we found something close0 of 4 points · 13 of 15 pass
Structured docs page: we found something close. An agent may struggle to tell where one topic in your docs ends and the next begins.
0 of 4 points · Medium, worth 4
- GEThttps://documentation.mailgun.com/HTTP 2001 heading (h1 to h3), 164 words in the raw HTML
- GEThttps://documentation.mailgun.com/docs/mailgun/quickstartHTTP 200Your docs home has one heading. This page it links to passes, with 15 headings and about 517 words on 31 Oct. Our rule reads the docs home.
How we test this:
- We check your docs page's raw HTML (no JavaScript run) has at least 2 headings (h1 to h3) with text and at least 150 visible words.
- Off the board, a docs page that comes back as markdown counts # to ### lines outside code blocks as its headings.
✓PassCode samples say their languageAR-READ-05markdown copy of the quickstart page: a code block with a language tag4 of 4 points · 13 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://documentation.mailgun.com/docs/mailgun/quickstart.mdHTTP 200markdown copy of the quickstart page https://documentation.mailgun.com/docs/mailgun/quickstart: a code block with a language tag
What our check kept, up to 60 lines or 6 KB
```bashHow we test this:
- On your docs surface, we look for a code block that carries a language tag: language-* or lang-* on <pre> or <code>, code-language-* on any element (a code block's wrapper, say), or a data-language or data-lang attribute.
- In markdown files, a fenced block with a language (```ts) counts.
- If no page shows one, we read the markdown copy each HTML page declares (a <link rel="alternate" type="text/markdown">, or its URL plus .md listed in your llms.txt), since many docs sites add the language label with JavaScript.
- If none of the pages we read is a quickstart or SDK page, a miss isn't counted: it can't fail you or withhold your score.
✓PassReadable pricingAR-READ-11raw text shows "Free" next to a month or year4 of 4 points · 15 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://www.mailgun.com/pricing/HTTP 200from our board config, linked from https://www.mailgun.com/; raw text shows "Free" with a period
What our check kept, up to 60 lines or 6 KB
GBP Need more? Get in touch with our team to tailor an Enterprise experience to fit your needs. The full service for high volume senders Recommended Free Test us out for $ 0 /mo 100 emails/day included Try for free Features include: 100 emails per day Ticket support RESTful email APIs and SMTP relay 1How we test this:
- We fetch the first homepage link with 'pricing' in its path, else /pricing (board companies: a pricing URL we confirmed by hand), and check it returns 200 and its raw text (no JavaScript run) shows a price or 'free' within 80 characters of month, mo, year or yr.
- Off the board, a pricing address that answers with JSON counts when it has a price field.
◐PartlyDocs in MarkdownLG-READ-03Agents get your docs as HTML only, not as Markdown3.4 of 4 points
Agents get your docs as HTML only, not as Markdown. An agent reading HTML spends its context on menus and markup, and may cut the page off before it reaches the part it needs.
3.4 of 4 points · Medium, worth 4 · 86% credit
- GEThttps://documentation.mailgun.com/HTTP 200docs page: answers as Markdown, but with an empty body
- GEThttps://documentation.mailgun.com/docs/mailgun/quickstartHTTP 200docs surface: answers Accept: text/markdown
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/nodejs_sdkHTTP 200docs surface: answers Accept: text/markdown
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/python_sdkHTTP 200docs surface: answers Accept: text/markdown
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/go_sdkHTTP 200docs surface: answers Accept: text/markdown
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/java_sdkHTTP 200docs surface: answers Accept: text/markdown
- GEThttps://documentation.mailgun.com/docs/mailgun/mcpHTTP 200docs surface: answers Accept: text/markdown
What our check kept, up to 60 lines or 6 KB
# Quickstart: Send Your First Email Send an email in under two minutes using your sandbox domain ## Step 1: Sign up 1. [Sign up for Mailgun](https://signup.mailgun.com/new/signup) (free) Info After creating your account, follow the guided setup in your [Mailgun Dashboard](https://app.mailgun.com/welcome-guide) to activate your account and create your first API key. Both of these things will need to be done during this setup in order for you to continue. You can then choose to continue with the dashboards guide to quickly send your first email, or you can grab your API key and continue below. 1. Go to [API Keys](https://app.mailgun.com/settings/api_security) in your dashboard 2. Copy your **Private API key** ## Step 2: Add Authorized Recipient First, add your email as an authorized recipient. This will send a verification email to that address. cURL ```bash curl -X POST \ "https://api.mailgun.net/v5/sandbox/auth_recipients?email=your-email@example.com" \ --user 'api:YOUR_API_KEY' ``` Node.js ```javascript fetch('https://api.mailgun.net/v5/sandbox/auth_recipients?email=your-email@example.com', { method: 'POST', headers: { 'Authorization': 'Basic ' + Buffer.from('api:YOUR_API_KEY').toString('base64') } }) .then(res => console.log('Status:', res.status)) .catch(err => console.log('Error:', err.message)); ``` Python ```python import requests response = requests.post( "https://api.mailgun.net/v5/sandbox/auth_recipients?email=your-email@example.com", auth=("api", "YOUR_API_KEY") ) print(f"Status: {response.status_code}") ``` Java ```java import java.net.URI; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; import java.util.Base64; public class Main { public static void main(String[] args) throws Exception {How we test this:
- On each docs page we read (up to 7), one Markdown answer with content passes the page: it answers Accept: text/markdown with text/markdown, declares a copy with <link rel="alternate" type="text/markdown"> that returns Markdown, or the address the page lands on, after redirects, ending in .md does (for one ending in a slash, both /page.md and /page/index.md).
- An empty answer doesn't count.
- The credit is the share of pages that pass.
- AFDocs, Cloudflare's isitagentready and is-agentic check it.
✓PassStructured dataAR-READ-08has an application/ld+json block2 of 2 points · 13 of 15 pass
2 of 2 points · Low, worth 2
- GEThttps://mailgun.com/HTTP 200has an application/ld+json block (redirected to https://www.mailgun.com/)
What our check kept, up to 60 lines or 6 KB
{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.mailgun.com\/","url":"https:\/\/www.mailgun.com\/","name":"Transactional Email API Service For Developers | Mailgun","isPartOf":{"@id":"https:\/\/www.mailgun.com\/#website"},"about":{"@id":"https:\/\/www.mailgun.com\/#organization"},"datePublished":"2025-06-30T05:17:31+00:00","dateModified":"2026-11-04T16:12:30+00:00","description":"Powerful Transactional Email APIs that enable you to send, receive, and track emails, built with developers in mind. Learn more today!","breadcrumb":{"@id":"https:\/\/www.mailgun.com\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.mailgun.com\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.mailgun.com\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home"}]},{"@type":"WebSite","@id":"https:\/\/www.mailgun.com\/#website","url":"https:\/\/www.mailgun.com\/","name":"Transactional Email API Service For Developers | Mailgun","description":"Powerful Transactional Email APIs that enable you to send, receive, and track emails, built with developers in mind. Learn more today!","publisher":{"@id":"https:\/\/www.mailgun.com\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.mailgun.com\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/www.mailgun.com\/#organization","name":"Transactional Email API Service For Developers | Mailgun","url":"https:\/\/www.mailgun.com\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/www.mailgun.com\/#\/schema\/logo\/image\/","url":"https:\/\/www.mailgun.com\/wp-content\/uploads\/2025\/06\/cropped-android-chrome-512x512-1.png","contentUrl":"https:\/\/www.mailgun.com\/wp-content\/uploads\/2025\/06\/cropped-android-chrome-512x512-1.png","width":512,"height":512,"caption":"Transactional Email API Service For Developers | Mailgun"},"image":{"@id":"https:\/\/www.mailgun.com\/#\/schema\/logo\/image\/"}}]}How we test this:
- We check your homepage's raw HTML has an application/ld+json block that parses as JSON and has @type or @context.
✓PassMachine-readable discovery fileAR-READ-06valid JSON2 of 2 points · 8 of 15 pass
2 of 2 points · Low, worth 2
- GEThttps://mailgun.com/.well-known/oauth-authorization-serverHTTP 200valid JSON (redirected to https://www.mailgun.com/.well-known/oauth-authorization-server/)
- GEThttps://mailgun.com/.well-known/oauth-protected-resourceHTTP 200valid JSON (redirected to https://www.mailgun.com/.well-known/oauth-protected-resource/)
- GEThttps://mailgun.com/.well-known/openid-configurationHTTP 404returned 404 (redirected to https://www.mailgun.com/.well-known/openid-configuration)
- GEThttps://mailgun.com/.well-known/api-catalogHTTP 404returned 404 (redirected to https://www.mailgun.com/.well-known/api-catalog)
- GEThttps://mailgun.com/.well-known/agent-card.jsonHTTP 404returned 404 (redirected to https://www.mailgun.com/.well-known/agent-card.json)
What our check kept, up to 60 lines or 6 KB
{"issuer":"https:\/\/www.mailgun.com","authorization_endpoint":"https:\/\/www.mailgun.com\/oauth\/authorize","token_endpoint":"https:\/\/www.mailgun.com\/oauth\/token","revocation_endpoint":"https:\/\/www.mailgun.com\/oauth\/revoke","response_types_supported":["code"],"grant_types_supported":["authorization_code","refresh_token"],"code_challenge_methods_supported":["S256"],"scopes_supported":["mcp"],"token_endpoint_auth_methods_supported":["none"],"client_id_metadata_document_supported":true,"authorization_response_iss_parameter_supported":true}How we test this:
- We fetch five standard .well-known files and check at least one returns 200 with valid JSON: oauth-authorization-server (RFC 8414), oauth-protected-resource (RFC 9728), openid-configuration, api-catalog (RFC 9727) and agent-card.json (A2A).
- This list is ours: AgentReady v2.0 doesn't name one.
- Off the board, on a miss, we also read oauth-protected-resource on the mcp., api. and docs. hosts of your domain, where that metadata usually lives, and it counts only with its resource field.
Act · 9 of 12 pass · 43.3 of 48 points
–Not countedMCP server or CLIAR-ACT-10we haven't confirmed this MCP server's tools yet (its tool list isn't confirmed)
Not in the score · Must, worth 10
- GEThttps://documentation.mailgun.com/docs/mailgun/mcpno answernot counted: we haven't confirmed this MCP server's tools yet (its tool list isn't confirmed)
How we test this:
- Passes when AR-ACT-03 passes (your docs surface names your own MCP server, not just a mention or a blog post about one; on the board, only an MCP server with a tool that acts on the product: send, manage or query, not only search docs, since AgentReady calls this "the interface an agent acts through"), or when your docs surface shows a CLI install: brew install, npm i -g, npm install -g, pipx install, uv tool install, go install, az extension add, or curl ... | sh (or | bash).
- A mention of MCP that isn't your own server, with no CLI install, isn't counted.
- For board companies, the CLI half counts only a command of the product's own CLI that we confirmed by hand, like az communication email send or twilio email:send, on the pages we read or on the docs page that shows it: an install alone could be any tool (an MCP setup guide installing pnpm, say).
- For a product inside a larger platform, the platform's MCP server or CLI counts when its docs show it covers the product.
- An MCP server earns both this check and AR-ACT-03, because AgentReady lists them as two items.
- If none of the pages we read is a quickstart or SDK page, a miss isn't counted: it can't fail you or withhold your score.
✓PassOpenAPI specAR-ACT-02OpenAPI 3.1.0, 165 paths7 of 7 points · 11 of 15 pass
7 of 7 points · High, worth 7
- GEThttps://documentation.mailgun.com/_bundle/docs/mailgun/api-reference/send/mailgun.yamlHTTP 200from our board config, linked from https://documentation.mailgun.com/docs/mailgun/api-reference/send/mailgun.md; OpenAPI 3.1.0, 165 paths
How we test this:
- We look for an OpenAPI or Swagger document: for board companies, a URL we confirmed by hand; then up to 2 links on your docs surface whose URL mentions openapi or swagger, or whose link text does for a .json or .yaml file (files on other sites count when your docs link them; an address written out in your llms.txt or another text file counts as a link, and its line as the link text); then /openapi.json and /openapi.yaml on your host and your docs host.
- Off the board, a .json or .yaml link under an llms.txt heading that names OpenAPI counts as a link to a spec, or, where that section has none, a link with no file extension, and on a miss we also try those two on the docs., developers. and api. hosts of your domain.
- It passes if one parses as JSON or YAML with an openapi or swagger key and at least one path.
- A spec over 10 MB counts as couldn't check.
✓Passnpm and PyPI packagesAR-ACT-06language page: npm install "npm install mailgun.js"; language page: pip install "pip install mailgun"7 of 7 points · 11 of 15 pass
7 of 7 points · High, worth 7
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/nodejs_sdkHTTP 200language page: npm install "npm install mailgun.js"
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/python_sdkHTTP 200language page: pip install "pip install mailgun"
What our check kept, up to 60 lines or 6 KB
npm install mailgun.js pip install mailgunHow we test this:
- On your docs surface we look for an npm install (npm, yarn, pnpm or bun) and a pip install (pip, poetry or uv) of a named package.
- Both must appear, on any of the pages (AgentReady: npm and PyPI).
- Off the board, uv tool install and pipx install also count as a pip install.
- Off the board, if one is missing we also read the markdown copy each HTML page declares (a <link rel="alternate" type="text/markdown">, or its URL plus .md listed in your llms.txt), then up to 2 pages your llms.txt names for that language.
- AgentReady v2.0 asks for SDKs and a CLI here; this check tests the npm and PyPI half, and a CLI counts under AR-ACT-10.
- If none of the pages we read is a quickstart or SDK page, a miss isn't counted: it can't fail you or withhold your score.
✓PassAuth an agent can follow (proxy)AR-ACT-01OAuth metadata parses, with issuer4 of 4 points · 12 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://mailgun.com/.well-known/oauth-authorization-serverHTTP 200OAuth metadata parses, with issuer (redirected to https://www.mailgun.com/.well-known/oauth-authorization-server/)
What our check kept, up to 60 lines or 6 KB
{"issuer":"https:\/\/www.mailgun.com","authorization_endpoint":"https:\/\/www.mailgun.com\/oauth\/authorize","token_endpoint":"https:\/\/www.mailgun.com\/oauth\/token","revocation_endpoint":"https:\/\/www.mailgun.com\/oauth\/revoke","response_types_supported":["code"],"grant_types_supported":["authorization_code","refresh_token"],"code_challenge_methods_supported":["S256"],"scopes_supported":["mcp"],"token_endpoint_auth_methods_supported":["none"],"client_id_metadata_document_supported":true,"authorization_response_iss_parameter_supported":true}How we test this:
- A stand-in: AgentReady asks for self-serve key generation with documented scopes, or OAuth metadata, and key sign-up can't be tested in code.
- It passes if OAuth metadata parses as JSON with the field its RFC requires (issuer for RFC 8414, resource for RFC 9728), or if your docs say "API key" or "API token" (also inside a placeholder like YOUR_API_KEY) within 200 characters of a documented auth header: an X-...-Key or X-...-Token header, a header named ...-Key or ...-Token, Authorization with Bearer, or "Bearer API key".
- The word "token" on its own doesn't count.
- For board companies we also read the authentication page their docs link.
- Off the board, OAuth metadata with its resource field on your mcp., api. or docs. host also counts.
- A board company whose API signs each request (like AWS Signature Version 4) or takes the key in the request body isn't counted: this stand-in can't judge that kind of auth either way.
- If none of the pages we read is a quickstart or SDK page, a miss isn't counted: it can't fail you or withhold your score.
✓PassEvery operation has an operationIdLG-ACT-01267 of 267 operations have an operationId4 of 4 points
4 of 4 points · Medium, worth 4
- GEThttps://documentation.mailgun.com/_bundle/docs/mailgun/api-reference/send/mailgun.yamlHTTP 200267 of 267 operations have an operationId
How we test this:
- In the OpenAPI spec AR-ACT-02 finds, we count the operations with a non-empty operationId.
- The credit is the share that have one.
- With no spec, it isn't counted: AR-ACT-02 already counts that.
✓PassMCP serverAR-ACT-03MCP page: mentions an MCP server; it doesn't name the tools4 of 4 points · 14 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://documentation.mailgun.com/docs/mailgun/mcpHTTP 200MCP page: mentions an MCP server; it doesn't name the tools
What our check kept, up to 60 lines or 6 KB
Mailgun MCP Server Skip to content Send Optimize Validate Inspect Mailgun.com Sinch.com Products Send Optimize Validate Inspect Mailgun.com Sinch.com Resources Search MHow we test this:
- On your docs surface we look for your own MCP server and quote the line: your name next to "MCP" ("Acme MCP server"), "our" or "official" MCP server, or an mcp.<your domain> address.
- Any other mention of "MCP server" or "Model Context Protocol", like a directory or an explainer, isn't counted: it can't fail you and it earns no points, because we can't tell the server is yours.
- A mention in a link to a blog post, or on an llms.txt line that links to one, doesn't count at all: a post about building a server isn't one you ship.
- For board companies we read the MCP page their docs link and list the tools it documents: a server that only searches your docs counts here, as AgentReady describes an MCP server as a "standard tool protocol for docs search and actions".
- We don't probe /mcp or call any server.
- Off the board, OAuth metadata with its resource field on your mcp. host also counts: it's the server's own file.
- If none of the pages we read is a quickstart or SDK page, a miss isn't counted: it can't fail you or withhold your score.
◐PartlyErrors have a schemaLG-ACT-02Your API spec doesn't say what an error looks like3.3 of 4 points
Your API spec doesn't say what an error looks like. Without a documented error shape, an agent may have to guess from the message why a call failed, and retry or give up wrongly.
3.3 of 4 points · Medium, worth 4 · 83% credit
- GEThttps://documentation.mailgun.com/_bundle/docs/mailgun/api-reference/send/mailgun.yamlHTTP 200221 of 267 operations declare an error response with a schema
How we test this:
- In the OpenAPI spec AR-ACT-02 finds, we count the operations that declare a 4xx, 5xx or default response with a schema, directly or through a $ref.
- The credit is the share that do.
- We note when they use application/problem+json (RFC 9457), the standard shape.
- With no spec, it isn't counted.
- The IETF's draft agent-friendly API profile, is-agentic and Alpic check it.
×FailTools for browser agentsAR-ACT-07We didn't find tools for browser agents in your homepage's HTML or inline scripts0 of 2 points · 0 of 15 pass
We didn't find tools for browser agents in your homepage's HTML or inline scripts. It costs a point, but it's only worth building if agents need to operate forms on your site. If they do, a browser agent may find no tools to call and have to click through instead.
0 of 2 points · Low, worth 2
- GEThttps://mailgun.com/HTTP 200no modelContext in the raw HTML or inline scripts (redirected to https://www.mailgun.com/)
How we test this:
- We check your homepage's raw HTML, inline scripts included, contains modelContext (AgentReady names document.modelContext).
- External scripts aren't fetched.
×FailAn agent skill is publishedLG-ACT-03Agents have no skill to follow for your product0 of 2 points
Agents have no skill to follow for your product. Without step-by-step skills, an agent may work out each task from reference pages, more slowly and with more mistakes.
0 of 2 points · Low, worth 2
- GEThttps://mailgun.com/.well-known/agent-skills/index.jsonHTTP 404returned 404 (redirected to https://www.mailgun.com/.well-known/agent-skills/index.json)
- GEThttps://documentation.mailgun.com/llms.txtHTTP 200no SKILL.md link or skills install on the docs we read
How we test this:
- Any of three passes: /.well-known/agent-skills/index.json on your site or your docs (or one a Link header names) lists a skill whose file answers; your docs or llms.txt link a SKILL.md that answers with a name and a description; or your docs show a skills install command, on a page we read or on up to 3 pages your docs or llms.txt link about skills or your CLI.
- An install is npx skills add, claude plugin install, a git clone into a skills folder, or your own command line running plugin install or skills add right after the word skill.
- An index under a folder, like /developer/, may list its files from that folder.
- Cloudflare's isitagentready, agenticplug and Alpic check it.
✓PassSign-in an MCP client can useLG-ACT-04S256, scopes and a way for a client to register2 of 2 points
2 of 2 points · Low, worth 2
- GEThttps://mailgun.com/.well-known/oauth-authorization-serverHTTP 200S256, scopes and a way for a client to register (redirected to https://www.mailgun.com/.well-known/oauth-authorization-server/)
What our check kept, up to 60 lines or 6 KB
{"issuer":"https:\/\/www.mailgun.com","authorization_endpoint":"https:\/\/www.mailgun.com\/oauth\/authorize","token_endpoint":"https:\/\/www.mailgun.com\/oauth\/token","revocation_endpoint":"https:\/\/www.mailgun.com\/oauth\/revoke","response_types_supported":["code"],"grant_types_supported":["authorization_code","refresh_token"],"code_challenge_methods_supported":["S256"],"scopes_supported":["mcp"],"token_endpoint_auth_methods_supported":["none"],"client_id_metadata_document_supported":true,"authorization_response_iss_parameter_supported":true}How we test this:
- We look for OAuth authorization server metadata (RFC 8414): at /.well-known/oauth-authorization-server on your site, through the authorization_servers your protected-resource metadata (RFC 9728) names, and on your mcp. host.
- It passes when it lists S256 in code_challenge_methods_supported, has scopes_supported, and has a registration_endpoint or client_id_metadata_document_supported, as the MCP authorization spec asks.
- With no OAuth metadata, it isn't counted.
✓PassInstall shown for four languagesEM-01language page: TypeScript/JavaScript "npm install mailgun.js"; language page: Python "pip install mailgun"; language page: Go "go get github.com/mailgun/mailgun-go/v5"; language page: Java "< artifactId >mailgun-java</ artifactId >"4 of 4 points · 6 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/nodejs_sdkHTTP 200language page: TypeScript/JavaScript "npm install mailgun.js"
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/python_sdkHTTP 200language page: Python "pip install mailgun"
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/go_sdkHTTP 200language page: Go "go get github.com/mailgun/mailgun-go/v5"
- GEThttps://documentation.mailgun.com/docs/mailgun/sdk/java_sdkHTTP 200language page: Java "< artifactId >mailgun-java</ artifactId >"
What our check kept, up to 60 lines or 6 KB
TypeScript/JavaScript: npm install mailgun.js Python: pip install mailgun Go: go get github.com/mailgun/mailgun-go/v5 Java: < artifactId >mailgun-java</ artifactId >How we test this:
- On your docs surface we look for an install in each of four languages: TypeScript/JavaScript (npm, yarn, pnpm or bun), Python (pip, poetry or uv), Go (go get) and Java (a Maven <artifactId> or a Gradle implementation line).
- All four must appear.
- This shows how to install, not that a package is official.
- If none of the pages we read is a quickstart or SDK page, a miss isn't counted: it can't fail you or withhold your score.
- Ours, not AgentReady's.
✓PassSend operation in the specEM-02the spec has POST /v3/{domain_name}/messages, POST /v3/{domain_name}/messages.mime, POST /v3/domains/{domain_name}/messages/{storage_key} and 3 more4 of 4 points · 11 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://documentation.mailgun.com/_bundle/docs/mailgun/api-reference/send/mailgun.yamlHTTP 200the spec has POST /v3/{domain_name}/messages, POST /v3/{domain_name}/messages.mime, POST /v3/domains/{domain_name}/messages/{storage_key} and 3 more
How we test this:
- In the OpenAPI spec AR-ACT-02 found, we look for a POST operation on a path containing mail, email, message or send.
- No spec counts as a fail.
- Ours, not AgentReady's.
✓PassFree tier in emailsEM-03free tier: "50,000 emails/month"4 of 4 points · 13 of 15 pass
4 of 4 points · Medium, worth 4
- GEThttps://www.mailgun.com/pricing/HTTP 200from our board config, linked from https://www.mailgun.com/; free tier: "50,000 emails/month"
What our check kept, up to 60 lines or 6 KB
nd pricing Send Mailgun Optimize pricing Optimize Mailgun Inspect pricing Inspect Mailgun Send Flexible plans built for email delivery I want to send 50,000 emails/month Currency $ USD € EUR £ GBP Need more? Get in touch with our team to tailor an Enterprise experience to fit your needs. The full service for high voluHow we test this:
- On the pricing page AR-READ-11 reads, we look for "free" within 300 characters of a number followed by emails, messages or sends and a period (a month, a day, or 30 days), like "3,000 emails/month" or "4,000 sends in any rolling 30-day window", in the raw text (no JavaScript run).
- A one-time allowance with no period doesn't count.
- Ours, not AgentReady's.
How we check: every check, its points and the thresholds, from the same code that runs the scan.
Something wrong? Report it to rahulu626@gmail.com
4Your next stepsPart 4 of 4
Your next steps
- 1Pick your fixes
- 2Hand them off
- 3Rescan once it's live
- 4Stay ahead of your category
- Then back to 1 when a rival passes you
Pick your fixes
Usually the founder or DevRel lead
3 fixes take Mailgun from 90 to 97, 2nd of 15 email APIs, past Loops, SendGrid, Bird (ex-SparkPost), Resend and 2 more.
Nothing copied yet from this browser.
Hand them off
To whoever ships it
Fix with AI writes each fix for whoever ships it: your coding agent, an engineer, product or marketing. Open it in Cursor, as a GitHub issue or in Linear, or copy it. Nothing runs until you send it.
Rescan once it's live
Usually the engineer, after the deploy
A rescan reads Mailgun again and shows what now passes, the new score and who you passed.
Last scan: 90 on 9 Nov, 8th of 15 email APIs.
Weekly, for 4 weeks. A calendar file: no email from us.Bookmark this page: it opens on our 9 Nov 2026 scan, with a live scan one press away.Stay ahead of your category
DevRel, the founder
Rivals ship too. Watch Mailgun with SendGrid and Loops, the nearest on the board: home keeps all three, and Rescan all there shows who moved.
Track it weekly, or scan from your terminal
Scan from your terminal
npx legible-cli mailgun
Add it for your coding agent
Adds a skill to your project. Ask your agent to use it, and it scans your live site, reads the real file behind each gap and helps write your own. It only publishes if you ask.
npx legible-cli skill
If Windows PowerShell blocks npx, type npx.cmd instead.
Get warned if this slips
A GitHub Action that runs in your own repo, once a week. It fails, naming the check, if something this site passes today stops passing. Each alert links back to the result. Add a Slack webhook as a repo secret named SLACK_WEBHOOK_URL, and a change also posts to your channel; nothing else is sent to us. Anything we can't be sure of only warns. GitHub notifies whoever created the job, depending on their settings. In a public repo, it turns scheduled jobs off after 60 days with no activity.
.github/workflows/legible.yml
5 fixes · copy, or open in Cursor, GitHub, Linear