SMTP2GO

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

User-agent: *
Disallow: /admin/
Disallow: /blog-ty/
Disallow: /call-ty/
Disallow: /contact-ty/
Disallow: /signup-ty/
Disallow: /signup-custom-ty/
Disallow: /subscription-confirmed/
Disallow: /slack-success/
Disallow: /ip-success/
Sitemap: https://www.smtp2go.com/sitemap_index.xml

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.

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.

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.

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

a line on the page: https://developers.smtp2go.com/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).

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

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="/main-sitemap.xsl"?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <sitemap>
    <loc>https://www.smtp2go.com/post-sitemap.xml</loc>
    <lastmod>2026-11-06T01:28:21+00:00</lastmod>
  </sitemap>
  <sitemap>
    <loc>https://www.smtp2go.com/page-sitemap.xml</loc>
    <lastmod>2026-11-06T01:28:21+00:00</lastmod>
  </sitemap>
  <sitemap>
    <loc>https://www.smtp2go.com/setupguide-sitemap.xml</loc>
    <lastmod>2026-11-06T01:28:21+00:00</lastmod>
  </sitemap>
</sitemapindex>

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.

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.

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.

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.

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

# SMTP2GO
 
> SMTP2GO is an email and SMS delivery service that sends, tracks, and reports on transactional and marketing messages over SMTP relay or a REST API. It's built for developers and businesses who want reliable inbox delivery without running their own mail infrastructure.
 
Founded in New Zealand in 2006, SMTP2GO handles delivery for 40,000+ businesses, with data centers in the US, Europe, and Australia. The content spans a few subdomains: marketing and setup live on smtp2go.com, API docs on developers.smtp2go.com, the help center on support.smtp2go.com, the account control panel on app.smtp2go.com, and uptime on smtp2gostatus.com. The developer docs also publish their own machine-readable index at https://developers.smtp2go.com/llms.txt.
 
## Product & Pricing
- [Product Tour](https://www.smtp2go.com/tour): Overview of delivery, reporting, the API, and email testing
- [Pricing](https://www.smtp2go.com/pricing): Plan tiers and the free account (1,000 emails/month)
- [Comparison](https://www.smtp2go.com/comparison): How SMTP2GO stacks up against other providers
- [Infrastructure](https://www.smtp2go.com/infrastructure): Multi data center setup and redundancy
- [FAQ](https://www.smtp2go.com/faq): Common questions about the service
- [Customer Success](https://www.smtp2go.com/customer-success): Case studies and customer reviews
 
## API & Developer Docs
- [API Introduction](https://developers.smtp2go.com/docs/introduction-guide): What the API does and how to start
- [Getting Started with the API](https://developers.smtp2go.com/docs/getting-started): First steps, keys, and setup
- [API Features Overview](https://developers.smtp2go.com/docs/api-features-guide): Full rundown of available API functionality
- [Endpoints](https://developers.smtp2go.com/docs/endpoints): List of API endpoints
- [API Reference](https://developers.smtp2go.com/reference): Interactive reference with examples and a test console
- [Send an Email](https://developers.smtp2go.com/docs/send-an-email): Walkthrough for the email/send endpoint
- [Templates](https://developers.smtp2go.com/docs/getting-started-with-templates): Using email templates via the API
- [Webhooks Overview](https://developers.smtp2go.com/docs/webhooks-overview): Event types and how webhooks work
- [MCP](https://developers.smtp2go.com/docs/mcp): Model Context Protocol support for AI agents
- [Official Libraries](https://developers.smtp2go.com/docs/official-libraries): SDKs and packages for common languages
- [SMTP Relay](https://developers.smtp2go.com/docs/smtp-relay): Connecting over SMTP instead of the API
 
## Setup & Integrations
- [Setup Guides Hub](https://www.smtp2go.com/setup): Search setup instructions plus generic SMTP/API config
- [All Setup Guides](https://www.smtp2go.com/setupguide/): Full list of app, service, and language guides
- [WordPress Plugin](https://developers.smtp2go.com/docs/wordpress-plugin): Official Email Made Easy plugin docs
- [cPanel/WHM Plugin](https://developers.smtp2go.com/docs/cpanelwhm-automation-plugin): Automation plugin for cPanel and WHM
- [Slack App](https://developers.smtp2go.com/docs/slack-app): Sending and notifications through Slack
 
## Support & Account
- [Help Center](https://support.smtp2go.com/hc/en-gb): Knowledge base and support articles
- [Contact](https://www.smtp2go.com/contact): Reach the support team
- [Log In / Control Panel](https://app.smtp2go.com): Account dashboard, reports, and API keys
- [System Status](https://smtp2gostatus.com/): Real-time uptime and historical performance
 
## Company
- [About](https://www.smtp2go.com/about): Company background and mission
- [Careers](https://www.smtp2go.com/jobs): Open roles
- [Resellers](https://www.smtp2go.com/resellers): Reseller program details
- [Affiliates](https://affiliates.smtp2go.com/): Affiliate program
- [Managed Service Providers](https://www.smtp2go.com/managed-service-providers): Offering for MSPs
 
## Other
- [Blog](https://www.smtp2go.com/blog): Articles on email deliverability and product news
- [Developer Docs llms.txt](https://developers.smtp2go.com/llms.txt): Machine-readable index of all docs pages and OpenAPI endpoints
- [Privacy Policy](https://www.smtp2go.com/privacy): How data is handled
- [Terms](https://www.smtp2go.com/terms): Terms of service

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".

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.

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.

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

<meta name="description" content="SMTP2GO is the scalable, reliable email deliverability solution. Worldwide servers, a robust API, and powerful reporting set us apart. Try our free plan!">

How we test this:

• We check your homepage's raw HTML (no JavaScript run) has a non-empty meta description or og:description.

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

<h2>Welcome</h2>
<h2>Guides</h2>
<h2>AI</h2>
<h2>Integration</h2>
<h2>Webhooks</h2>
<h1>Introduction</h1>
<h2>Welcome!</h2>
<h2>What is SMTP2GO?</h2>
<h2>API</h2>
<h2>Support</h2>

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.

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

```json

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.

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

SMTP2GO Pricing | Plans From $15/mo (Free Tier Available) | SMTP2GO SMTP2GO Email delivery done right. Pricing Product Tour Overview Managed Service Providers Education Customers Res

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.

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

---
updatedAt: 2026-04-05T20:45:57.000Z
agentTools:
  projectIndex: https://developers.smtp2go.com/llms.txt
---

# Introduction

## Welcome!

Welcome to our new and updated API documentation. Let us know any feedback you have.

## What is SMTP2GO?

[SMTP2GO](https://www.smtp2go.com/) is a scalable email and SMS service provider that simplifies delivery for everyday senders and businesses, ensuring their messages arrive reliably and securely. Integrate using [SMTP](https://developers.smtp2go.com/docs/smtp-relay) or [API](https://developers.smtp2go.com/reference/general-api-resources), monitor the status of emails with real-time tracking and reporting tools for improved insights, and benefit from a knowledgeable support team available in all time zones.

## API

The SMTP2GO API allows you to programmatically send emails or SMS messages, access reporting and statistics, and manage account features using HTTP requests. Easily integrate to automate tasks without having to make changes in the App.

Whether you are an existing customer or have recently joined, the “[Getting Started with the API](https://developers.smtp2go.com/docs/getting-started)” page and welcome section will take you through the basic steps to get set up and utilize the API.

The [API Features Overview](https://developers.smtp2go.com/docs/api-features-guide) covers the functionality we offer through the API so you can make the most of your account. The [API Reference](https://developers.smtp2go.com/reference/) section is where you can discover examples, create requests and test endpoints.

If you don't have an SMTP2GO account, you'll need to create one to utilize the service. You can [sign up for a free account](https://www.smtp2go.com/pricing/) and get set up within minutes. Our [Getting Started with SMTP2GO](https://support.smtp2go.com/hc/en-gb/articles/12747932085145-Getting-Started-with-SMTP2GO) article gives an overview of the steps required.

## Support

If you have questions or encounter an error when using SMTP2GO, please [contact](https://www.smtp2go.com/contact/) our support team who can assist further. In your support request, please provide as much detail as possible including errors, your originating IP address and any further relevant information (such as your API request and the request\_id if using the API).

You can visit the [Status](https://smtp2gostatus.com/) page which features real-time updates from our servers and provides you with a concise historical graph of previous system performance.

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.

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

[{
  "@context": "https://schema.org/",
  "@type": "Organization",
  "@id": "https://www.smtp2go.com#Organization",
  "name": "SMTP2GO",
  "url": "https://www.smtp2go.com",
  "sameAs": [],
  "legalName": "Sand Dune Mail Limited",
  "logo": {
    "@type": "ImageObject",
    "url": "https://www.smtp2go.com/assets/images/logo.png",
    "width": "160",
    "height": "50"
  },
  "contactPoint": {
    "@type": "ContactPoint",
    "contactType": "general",
    "telephone": "+1 855 269 5305",
    "url": "https://www.smtp2go.com/contact/"
  }
}]

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.

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.

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

searching API endpoints plus executing API requests. The documentation discovery tools may be available without authentication. API execution through execute-request requires an SMTP2GO API key in the X-Smtp2go-Api-Key request header. Prefer a packaged, task-specific capability over a live tool server? See Skills

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.

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.

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.

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

s for listing/searching API endpoints plus executing API requests. The documentation discovery tools may be available without authentication. API execution through execute-request requires an SMTP2GO API key in the X-Smtp2go-Api-Key request header. Prefer a packaged, task-specific capability over a live tool server? See Skills . Prerequisites Every client on this page connects directly to the remote serv

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.

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.

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

f the sender address is not verified in your SMTP2GO account. Confirm it works After configuring the server, your MCP client should show these tools: list-endpoints get-endpoint search-endpoints execute-request get-server-variables Try a read-only discovery action first, such as searching for email/send or listin

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.

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.

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.

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

{"$schema":"https://schemas.agentskills.io/discovery/0.2.0/schema.json","skills":[{"name":"read-the-docs","description":"Guide to the documentation available at https://developers.smtp2go.com. Points to an llms.txt summary with links to every doc, reference, changelog, and custom page.","type":"skill-md","url":"https://developers.smtp2go.com/.well-known/agent-skills/read-the-docs/SKILL.md","digest":"sha256:0d6798c8883635fcc59f1aeff2627a0f14db4a9eb83dea7741eb5145a5d67d8b"}]}

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.

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.

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.

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.

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

your questions API resources SMTP2GO API documentation Join over 40,000 people and businesses using SMTP2GO. Get started with our free plan for up to 1,000 emails per month. Sign Up Free No credit card required How many emails do you need to send each month? How many emails do you send per month? 1 K 10 K 40 K 100 K 250

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.