resend.com

Whether agents can crawl you, find you in the registries and searches they check, and trust what they find.

• ✓Sitemap present & freshrequired4/4

  Sitemap at https://resend.com/sitemap.xml: 166 entries, freshest <lastmod> 2026-08-12 (5 days ago)

  Resolved the sitemap from robots.txt or /sitemap.xml, validated XML, and checked lastmod freshness

  spec ↗report issue
• ✓Brand search discoverabilityrequired4/4

  Both searches ("Resend" and "Resend developer tools") cited resend.com: https://resend.com/products/marketing-emails, https://resend.com/features/broadcasts, https://resend.com/docs/api-reference/broadcasts/get-broadcast-metrics, https://www.resend.com/docs/dashboard/webhooks/, https://www.resend.com/docs/dashboard/webhooks/how-to-store-webhooks-data

  Ran clean brand-name web searches and checked whether your domain is cited in the results

  report issue
• ✓MCP registry listingsrecommended4/4

  /.well-known/mcp/server-card.json serves JSON; searched "resend.com" and "Resend": listed in official MCP registry, Glama, Smithery (3 of 3 reachable registries)

  Queried the official MCP registry, Smithery, Glama, and PulseMCP for servers matching your domain

  spec ↗report issue

Whether your robots policy, bot protection, and agent guidance actively admit AI agents instead of blocking them.

• ✓robots.txt present & parseablerequired2/2

  /robots.txt parses: 1 User-agent group(s), 1 Sitemap line(s)

  Fetched /robots.txt and validated it parses as a robots policy

  spec ↗report issue
• ✓AI crawler policyrequired5/5

  All 12 AI crawler user-agents (GPTBot, ClaudeBot, PerplexityBot, …) are allowed at / by robots.txt

  Evaluated robots.txt groups for the major AI agent user-agents (GPTBot, ClaudeBot, PerplexityBot, …)

  report issue
• ✓Content Signals directivesemerging2/2

  1 valid Content-Signal line(s) in robots.txt (e.g. `Content-Signal: ai-train=yes, search=yes, ai-input=yes`)

  Looked for Content-Signal lines in robots.txt

  spec ↗report issue
• ✓Agent user-agent paritybetarequired4/4

  All three UAs get HTTP 200; bot bodies are ClaudeBot 100%, GPTBot 100% of the browser response (410195 bytes)

  Compared responses served to browser and AI-agent user-agents (informational while in beta)

  report issue
• ✗agents.mdrecommended0/3

  No agents.md: https://resend.com/agents.md → HTTP 404, https://resend.com/AGENTS.md → HTTP 404

  fix → Add /agents.md: what agents may do on your site, key URLs, auth, rate limits, and who to contact.

  Fetched /agents.md and checked for substantive agent guidance

  spec ↗report issue

Whether your pages carry machine-readable identity: structured data, llms.txt, clear copy an agent can quote.

• ✓Homepage states what you arerequired3/3

  Homepage clarity rated 5/5 — an agent can confidently say what this company does (model's one-sentence read: "Resend is an email API for developers to send transactional and marketing emails at scale, offering tools for integration, deliverability, and email creation.")

  An LLM read your homepage as an agent would and rated how confidently it could say what you do

  report issue
• ✓OpenGraph / social metadatarecommended2/2

  Homepage has og:title, og:description, and og:image (twitter:card="summary_large_image" present)

  Parsed homepage og:title / og:description / og:image and twitter:card meta tags

  spec ↗report issue
• ✓llms.txtrecommended4/4

  /llms.txt is valid llmstxt.org shape: H1 "Resend", 46 markdown link(s)

  Fetched /llms.txt and validated it against the llmstxt.org shape (H1, summary, curated links)

  spec ↗report issue
• ✓llms-full.txtbonusrecommended2/2

  /llms-full.txt serves 8036 chars of markdown

  Fetched /llms-full.txt and checked for substantial inline markdown content

  spec ↗report issue
• ✓JSON-LD structured datarequired4/4

  6 JSON-LD block(s) on homepage and pricing page (types: Organization, WebSite, SoftwareApplication, WebPage, BreadcrumbList, FAQPage); Organization block is well-formed

  Extracted and validated application/ld+json blocks on the homepage and pricing page

  spec ↗report issue
• ✓Markdown content negotiationrecommended3/3

  https://resend.com/ returns markdown for `Accept: text/markdown` (content-type text/markdown)

  Requested key pages with Accept: text/markdown and probed .md twin URLs

  report issue

Whether the artifacts an agent needs to build on you — docs, API specs, SDKs, MCP servers — exist and are findable.

• ✓Developer resource discoverabilityrecommended3/3

  Search "Resend API documentation" cited your own domain: https://resend.com/docs/llms.txt, https://resend.com/docs/api-reference, https://resend.com/docs/api-reference/introduction, https://resend.com/docs/api-reference/emails, https://resend.com/

  Searched for your brand with developer-keyword suffixes and checked which official resources are cited

  report issue
• ✓OpenAPI spec discoverablerequired5/5

  OpenAPI spec found at https://resend.com/openapi.json (version 3.0.3)

  Probed standard OpenAPI locations and docs links for a fetchable, parseable spec

  spec ↗report issue
• ✓Docs discoverablerequired4/4

  Docs found at https://resend.com/docs/introduction (via homepage link, 1593 chars of readable text)

  Followed homepage nav/footer links and probed /docs, /developers, docs.{domain}

  report issue
• ✓MCP server discoveryrequired5/5

  Valid MCP server card at https://resend.com/.well-known/mcp/server-card.json: name "resend", endpoint https://mcp.resend.com/mcp

  Probed /.well-known/mcp/server-card.json, mcp.json, and docs mentions for an MCP endpoint

  spec ↗report issue
• ✓npm SDKrecommended2/2

  Official npm package "resend" (verified via repository under the resend GitHub org (git+https://github.com/resend/resend-node.git)): latest 6.20.0 published 2026-08-13

  Searched the npm registry for an official, domain-verified SDK package

  report issue
• ✗PyPI SDKrecommended0/2

  No official PyPI SDK found: probed 4 candidate(s) (resend, resend-sdk, resendapi, resend-python) — found but not domain-verified: resend

  fix → Publish an official Python SDK (suggest "resend") with your domain in the project URLs so agents can verify it's official.

  Searched PyPI for an official, domain-verified SDK package

  report issue

Whether your specs, docs, and tools are complete and descriptive enough for an agent to use them without guessing.

• ◐OpenAPI validity & qualityrecommended1.5/3

  Spec at https://resend.com/openapi.json: 5/7 quality criteria passed (47 paths, 83 operations) — failing: info.description ≥ 50 chars; ≥ 70% of operations have operationId

  fix → Spec fails: info.description ≥ 50 chars; ≥ 70% of operations have operationId. Agents generate calls directly from your spec — descriptions and securitySchemes are load-bearing.

  Linted the spec: descriptions, operationIds, securitySchemes, servers

  report issue
• ◐Docs qualityrecommended1.5/3

  Docs at https://resend.com/docs/introduction scored clarity 4/5, completeness 3/5, runnable examples 1/5, agent-friendliness 2/5 (mean 2.5/5)

  fix → Docs scored 1/5 on runnable examples. The documentation heavily relies on external links and a full documentation index, which an agent following the docs literally would not be able to access directly without further instructions.

  An LLM rated your docs for clarity, completeness, runnable examples, and agent-friendliness

  report issue
• ✗Quickstart / getting startedrecommended0/2

  Quickstart page https://resend.com/docs#quickstart exists but contains no code block (<pre> or fenced code)

  fix → Add a copy-pasteable code example (auth → first API call) to your quickstart — agents follow it literally.

  Looked for a quickstart/getting-started guide containing code blocks

  report issue
• —MCP tool qualityrecommendedna

  MCP endpoint is auth-gated — tools could not be listed unauthenticated

  Linted listed tools for descriptions, typed input schemas, and naming

  report issue

Response hygiene, TLS and redirect discipline, and security contact channels agents depend on at runtime.

• ✓TLS & redirect hygienerequired2/2

  http://resend.com/ upgrades to https in 1 hop(s), 1 redirect(s) total, final HTTP 200; HSTS present

  Checked http→https redirect behavior, chain length, and TLS health

  report issue
• ✓Response speed & weightrequired1/1

  Homepage TTFB 282ms, payload 401KB, Content-Encoding: br

  Measured homepage TTFB, payload size, and compression

  report issue
• ✗security.txtrecommended0/1

  security.txt present at https://resend.com/.well-known/security.txt but missing required field(s): Expires

  fix → Add Expires to your security.txt — both are required by RFC 9116.

  Fetched /.well-known/security.txt and validated Contact + Expires

  spec ↗report issue

Whether agents can discover your auth model machine-readably (OAuth metadata) and follow documented steps to credentials.

• ✓OAuth authorization server metadatarecommended3/3

  Valid RFC 8414 metadata at https://resend.com/.well-known/oauth-authorization-server: issuer https://api.resend.com, PKCE S256, dynamic client registration at https://api.resend.com/oauth/register

  Fetched /.well-known/oauth-authorization-server (and openid-configuration fallback)

  spec ↗report issue
• ✓OAuth protected resource metadatarecommended2/2

  Valid RFC 9728 metadata at https://resend.com/.well-known/oauth-protected-resource: resource https://api.resend.com, 1 authorization server(s) (https://api.resend.com)

  Fetched /.well-known/oauth-protected-resource

  spec ↗report issue
• ✓Auth documentationrecommended2/2

  Auth documentation found at https://resend.com/auth.md (4686 chars, with code examples)

  Looked for /auth.md or an authentication docs page with code examples

  report issue

Whether pricing is discoverable and machine-readable, and whether you support agent payment protocols.

• ✓Pricing discoverablerequired5/5

  Pricing page found at https://resend.com/pricing (via homepage link) with legible price signals ("$20 / moYour plan already come").

  Followed nav/footer links and probed /pricing for a page with legible price signals

  report issue
• ✓Machine-readable pricingrecommended5/5

  LLM extracted 3 numerically-priced plan(s) from https://resend.com/pricing at confidence 0.90: Domains Add-on $ 20/month; Dedicated IPs Add-on $ 30/month; Free $ 0/month; Pro (no listed price); Scale (no listed price); Enterprise (contact sales).

  Looked for Offer JSON-LD, then had an LLM attempt structured extraction of your plans

  spec ↗report issue
• ✗x402 payment supportbonusrecommended0/2

  /.well-known/x402 returned HTTP 404. API probe GET https://api.resend.com/emails returned HTTP 401 without x402 payment requirements. No x402 support detected (bonus check — absence costs nothing).

  fix → Support x402: serve payment requirements at /.well-known/x402, or answer unauthenticated API calls with HTTP 402 plus an x402 payment-requirements payload (x402Version, accepts[]).

  Probed /.well-known/x402 and API endpoints for HTTP 402 payment-required envelopes

  spec ↗report issue
• ✗AP2 readinessemerging0/1

  No AP2 hints found — scanned llms.txt, docs page (https://resend.com/docs/introduction), OpenAPI spec (https://resend.com/openapi.json); /.well-known/ap2 returned HTTP 404.

  fix → Adopt AP2 to accept delegated agent payments — see https://ap2-protocol.org.

  Scanned fetched artifacts and well-known paths for AP2 hints

  spec ↗report issue
• ✗Agentic Commerce Protocolemerging0/1

  No Agentic Commerce Protocol hints found — scanned llms.txt, docs page (https://resend.com/docs/introduction), OpenAPI spec (https://resend.com/openapi.json); /.well-known/acp returned HTTP 404.

  fix → Adopt the Agentic Commerce Protocol so agent checkouts can complete against your store — see https://developers.openai.com/commerce.

  Scanned docs and specs for agentic checkout endpoints

  spec ↗report issue
• ✗Other agent payment protocolsbonusemerging0/1

  No UCP/MPP hints found — scanned llms.txt, docs page (https://resend.com/docs/introduction), OpenAPI spec (https://resend.com/openapi.json).

  fix → Track emerging agent payment protocols (UCP, MPP) and adopt the ones your buyers' agents use.

  Scanned fetched artifacts for UCP/MPP protocol hints

  report issue

Whether an end user's agent can operate on their behalf: working MCP tools, published skills, agent configs.

• —Agent skill publishedbonusemergingna

  Requires the analysis phase — not yet evaluated

  Checked /skill.md, /.well-known/skills/, and skills.sh for published agent skills

  report issue
• ✓MCP handshake & tools listrequired4/4

  MCP endpoint https://mcp.resend.com/mcp is auth-gated (HTTP 401) and advertises resolvable RFC 9728 resource metadata in WWW-Authenticate — properly advertised auth gate

  Performed a streamable-HTTP initialize + tools/list against the MCP endpoint

  spec ↗report issue
• —Agent configs in public repobonusemergingna

  Requires the analysis phase — not yet evaluated

  Checked your public GitHub org's main repos for AGENTS.md / .claude / .cursor configs

  report issue

Whether the site itself is legible to non-rendering and browser agents: semantic HTML, no JS walls, accessibility.

• ✗NLWeb endpointemerging0/1

  No NLWeb endpoint detected: /.well-known/nlweb.json returned HTTP 404 (text/html); GET /ask?query=hello returned HTTP 404 (text/html)

  fix → Consider exposing an NLWeb /ask endpoint (and /.well-known/nlweb.json) for conversational access to your content.

  Probed /.well-known/nlweb.json and the /ask endpoint

  spec ↗report issue
• ✗Semantic HTML structurerequired0/3

  Only 2/6 semantic signals present on the homepage (missing: <main> landmark, <nav> landmark, no heading-level skips, text-to-markup ratio ≥ 0.10)

  fix → Add landmark elements and a clean heading hierarchy — missing: <main> landmark, <nav> landmark, no heading-level skips, text-to-markup ratio ≥ 0.10.

  Scored landmark elements, heading hierarchy, and text-to-markup ratio on the homepage

  report issue
• ✓Content readable without JavaScriptrequired2/2

  Homepage raw HTML contains 13636 chars of visible text without JavaScript

  Measured visible text in the raw, unrendered homepage HTML

  report issue
• ✓Accessibility basicsrequired2/2

  Homepage accessibility: 4/5 checks passed — failing: labeled inputs (3/3 unlabeled)

  Static checks: lang attribute, title, alt coverage, labeled inputs, landmarks

  report issue
• ✗WebMCPemerging0/1

  No WebMCP evidence on homepage: no application/webmcp script and no navigator.modelContext reference

  fix → Consider WebMCP to expose page actions as tools to browser agents.

  Looked for WebMCP script declarations on the homepage

  spec ↗report issue