Legible
Scan APIChrome extension

Mailgun

mailgun.com

An AI agent's path through Mailgun

  1. FindCan an agent get in and find what it needs?Weakest step81/100

    4 of 5 pass · 1 gap

  2. ReadCan it read what it finds?94/100

    11 of 13 pass · 2 gaps

  3. 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.

See the 5 fixes ↓See all 31 checks ↓
Rank
8th 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.

What 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

FailFind stepFix 1 of 5+7 pointsEffort: minutes, our estimate

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)

PassFrom Mailtrap, on our email API board, as of 9 Nov 2026

What the leader shippedView their file ↗

Their file
a Link header: https://mailtrap.io/llms.txt

More examples

Why 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 OKAI agents allowed, homepage reachable: also read here
  • /200 OKOur scanner gets in: also read hereReadable without JavaScript: also read hereMeta description: PassStructured data: PassTools for browser agents: Fail
  • /leaderfile-check-404404 · expected, it's a probeReal 404s: Pass
  • /llms.txt404 not foundllms.txt: also read here
  • /.well-known/oauth-authorization-server200 OKMachine-readable discovery file: also read hereAuth an agent can follow (proxy): PassSign-in an MCP client can use: Pass
  • /.well-known/oauth-protected-resource200 OKMachine-readable discovery file: also read here
  • /.well-known/openid-configuration404 not foundMachine-readable discovery file: also read here
  • /.well-known/api-catalog404 not foundMachine-readable discovery file: also read here
  • /.well-known/agent-card.json404 not foundMachine-readable discovery file: also read here
  • /.well-known/agent-skills/index.json404 not found

documentation.mailgun.com

  • /robots.txt404 not foundAI agents allowed, homepage reachable: also read here
  • /200 OKOur scanner gets in: also read hereDocs page: PassReadable without JavaScript: also read hereDocs readable without a login: also read hereDocs pages fit an agent's context: also read here
  • /docs/mailgun/quickstart200 OKReadable without JavaScript: also read hereDocs readable without a login: also read hereDocs pages fit an agent's context: also read here
  • /docs/mailgun/sdk/nodejs_sdk200 OKReadable without JavaScript: also read hereDocs readable without a login: also read hereDocs pages fit an agent's context: also read herenpm and PyPI packages: also read hereInstall shown for four languages: also read here
  • /docs/mailgun/sdk/python_sdk200 OKReadable without JavaScript: also read hereDocs readable without a login: also read hereDocs pages fit an agent's context: also read herenpm and PyPI packages: also read hereInstall shown for four languages: also read here
  • /docs/mailgun/sdk/go_sdk200 OKReadable without JavaScript: also read hereDocs readable without a login: also read hereDocs pages fit an agent's context: also read hereInstall shown for four languages: also read here
  • /docs/mailgun/sdk/java_sdk200 OKReadable without JavaScript: also read hereDocs readable without a login: also read hereDocs pages fit an agent's context: also read hereInstall shown for four languages: also read here
  • /docs/mailgun/mcp200 OKReadable without JavaScript: also read hereDocs readable without a login: also read hereDocs pages fit an agent's context: also read hereMCP server or CLI: Not countedMCP server: Pass
  • /llms.txt200 OKllms.txt: also read herellms.txt links work, and it fits: Pass
  • /docs/mailgun/quickstart.md200 OKCode samples say their language: Pass
  • /_bundle/docs/mailgun/api-reference/send/mailgun.yaml200 OKOpenAPI spec: PassEvery operation has an operationId: PassSend operation in the spec: Pass

www.mailgun.com

  • /sitemap_index.xml200 OKSitemap: Pass
  • /pricing/200 OKReadable pricing: PassFree 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.

We store your email, this domain and its gaps, to reply. Nothing else. To be removed, email rahulu626@gmail.com

How it comparesPart 2 of 4

How Mailgun compares

Score after each fix

Mailtrap, the leader, at 99
  1. Nowscore 90rank 8
  2. +1 fixscore 94rank =5level with Postmark
  3. +2 fixesscore 97rank 2past Bird (ex-SparkPost), Resend, Brevo and Postmark
  4. +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.

  1. FindFind: 81, median 100, best 100.
  2. ReadRead: 94, median 95, best 100.
  3. ActAct: 90, median 82, best 96.

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

  1. Loops92+2
  2. SendGrid92+2
  3. Mailgun90
  4. Mailchimp Transactional88−2
  5. 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

Every 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

    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 BLOCK

    How 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

    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

    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

    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

    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

    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

    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

    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

    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 integ

    How 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

    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

    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

    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

    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

    What our check kept, up to 60 lines or 6 KB

    ```bash

    How 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

    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 1

    How 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

    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

    • https://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

    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

    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

    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

    What our check kept, up to 60 lines or 6 KB

    npm install mailgun.js
    pip install mailgun

    How 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

    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

    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

    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 M

    How 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

    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

    • https://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

    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

    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

    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

    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

    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 volu

    How 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

Your next stepsPart 4 of 4

Your next steps

  1. Pick your fixes
  2. Hand them off
  3. Rescan once it's live
  4. Stay ahead of your category
  5. Then back to 1 when a rival passes you
  1. 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.

  2. 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.

  3. 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.
  4. 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 a rival

No sign-up. Checks the files and URLs agents read. It doesn't test an agent using your product, or whether ChatGPT recommends you.

5 fixes · copy, or open in Cursor, GitHub, Linear

Share Mailgun's result

From our 9 Nov 2026 scan.

  • LinkThis result, so whoever opens it sees the same.
  • A line to postWhat it passes, and a way to check their own.

Cards with a place, and README badges, are for the top 3 on a board. When a rescan lifts your score, you can share the jump.