Issue 1: who has what today

From our 29 Oct 2026 scan of 15 email APIs, the first one.

Issue 1, 29 October 2026. We checked 15 email APIs for the files and pages AI coding agents read before they write code against your API. Resend and Mailtrap lead at 96. Of everything the two leaders ship, the rarest is install commands for all four big languages: only 6 of the 15 show them. Every result links to the file we fetched, and if we got one wrong, tell us and we'll log the fix on the method page.

What changed on the board

Nothing to compare in this one: it's the first scan. Issue 2 says what changed next.

The whole board at a glance

● pass · × fail · ? couldn't check · – not counted. Highest score at the top, and the table scrolls sideways on a phone.

Company	AR-FIND-01	AR-FIND-02	AR-FIND-03	AR-READ-01	AR-READ-02	AR-READ-03	AR-READ-04	AR-READ-05	AR-READ-06	AR-READ-07	AR-READ-08	AR-READ-11	AR-ACT-01	AR-ACT-02	AR-ACT-03	AR-ACT-06	AR-ACT-07	AR-ACT-10	EM-01	EM-02	EM-03
Mailtrap	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass
Resend	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass
Bird (ex-SparkPost)	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Fail	Pass	Pass
Postmark	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Fail	Pass	Pass
Brevo	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Couldn't check	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Not counted	Fail	Pass	Pass
Mailgun	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Not counted	Pass	Pass	Pass
Mailjet	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Couldn't check	Pass	Fail	Not counted	Pass	Pass	Pass
Loops	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Fail	Pass	Fail	Pass	Pass
SendGrid	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Fail	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass
MailerSend	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Fail	Pass	Pass	Fail	Pass
Plunk	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Fail	Pass	Fail	Pass	Pass
Mailchimp Transactional	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Not counted	Pass	Pass	Pass	Fail	Pass	Fail	Pass	Fail
SMTP2GO	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Pass	Pass	Pass	Pass	Fail	Pass	Fail	Fail	Pass	Fail	Fail	Pass
Amazon SES	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Fail	Pass	Pass	Pass	Not counted	Fail	Pass	Fail	Fail	Pass	Fail	Fail	Pass
Azure Communication Services Email	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Pass	Fail	Fail	Fail	Pass	Not counted	Fail	Pass	Pass	Fail	Pass	Fail	Fail	Fail

Who has what

Each check, rarest on the board first. Each name opens that company's result, with the URL we fetched for every check.

Tools for browser agents
AR-ACT-07 · 0 of 15 pass
None of the 15 passes our check yet.
Something close we found since this scan, which our check doesn't count: Bird (ex-SparkPost) and Postmark
Not yet: Amazon SES, Azure Communication Services Email, Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Resend, SendGrid and SMTP2GO
Install shown for four languages
EM-01 · 6 of 15 pass
Pass: MailerSend, Mailgun, Mailjet, Mailtrap, Resend and SendGrid
Not yet: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, Plunk, Postmark and SMTP2GO
Best example, Resend: resend.com/docs/send-with-nodejs.md
Machine-readable discovery file
AR-READ-06 · 8 of 15 pass
Pass: Bird (ex-SparkPost), Loops, MailerSend, Mailgun, Mailjet, Mailtrap, Postmark and Resend
Not yet: Amazon SES, Azure Communication Services Email, Mailchimp Transactional, Plunk, SendGrid and SMTP2GO
Couldn't check: Brevo
Best example, Resend: resend.com/.well-known/oauth-authorization-server
OpenAPI spec
AR-ACT-02 · 11 of 15 pass
Pass: Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend and SendGrid
Not yet: Amazon SES, Azure Communication Services Email, MailerSend and SMTP2GO
Best example, Resend: raw.githubusercontent.com/resend/resend-openapi/main/resend.json
npm and PyPI packages
AR-ACT-06 · 11 of 15 pass
Pass: Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Postmark, Resend and SendGrid
Something close we found since this scan, which our check doesn't count: SMTP2GO
Not yet: Amazon SES, Loops and Plunk
Best example, Resend: resend.com/docs/send-with-nodejs.md
Send operation in the spec
EM-02 · 11 of 15 pass
Pass: Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend and SendGrid
Not yet: Amazon SES, Azure Communication Services Email, MailerSend and SMTP2GO
Best example, Mailtrap: raw.githubusercontent.com/mailtrap/mailtrap-openapi/main/specs/email-sending-transactional.openapi.yml
Auth an agent can follow (proxy)
AR-ACT-01 · 12 of 15 pass
Pass: Bird (ex-SparkPost), Brevo, Loops, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Not counted: Amazon SES, Azure Communication Services Email and Mailchimp Transactional
Best example, Mailtrap: docs.mailtrap.io/getting-started/email-api-smtp
MCP server or CLI
AR-ACT-10 · 12 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Loops, Mailchimp Transactional, MailerSend, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Not counted: Brevo, Mailgun and Mailjet
Best example, Mailtrap: raw.githubusercontent.com/mailtrap/mailtrap-mcp/main/README.md
Structured docs page
AR-READ-04 · 13 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Something close we found since this scan, which our check doesn't count: Mailgun and Mailjet
Best example, Resend: resend.com/docs
Code samples say their language
AR-READ-05 · 13 of 15 pass
Pass: Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Something close we found since this scan, which our check doesn't count: MailerSend
Not yet: Amazon SES
Best example, Mailtrap: raw.githubusercontent.com/mailtrap/mailtrap-mcp/main/README.md
Structured data
AR-READ-08 · 13 of 15 pass
Pass: Amazon SES, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend and SMTP2GO
Not yet: Azure Communication Services Email and SendGrid
Best example, Resend: resend.com
Free tier in emails
EM-03 · 13 of 15 pass
Pass: Amazon SES, Bird (ex-SparkPost), Brevo, Loops, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Not yet: Azure Communication Services Email and Mailchimp Transactional
Best example, Resend: resend.com/pricing
llms.txt
AR-READ-07 · 14 of 15 pass
Pass: Amazon SES, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Not yet: Azure Communication Services Email
Best example, Mailtrap: mailtrap.io/llms.txt
MCP server
AR-ACT-03 · 14 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Couldn't check: Mailjet
Best example, Mailtrap: raw.githubusercontent.com/mailtrap/mailtrap-mcp/main/README.md
AI agents allowed, homepage reachable
AR-FIND-01 · 15 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Best example, Resend: resend.com
Docs page
AR-FIND-02 · 15 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Best example, Mailtrap: docs.mailtrap.io/developers
Sitemap
AR-FIND-03 · 15 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Best example, Resend: resend.com/sitemap.xml
Readable without JavaScript
AR-READ-01 · 15 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Best example, Mailtrap: mailtrap.io
Real 404s
AR-READ-02 · 15 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Best example, Resend: resend.com/leaderfile-check-404
Meta description
AR-READ-03 · 15 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Best example, Mailtrap: mailtrap.io
Readable pricing
AR-READ-11 · 15 of 15 pass
Pass: Amazon SES, Azure Communication Services Email, Bird (ex-SparkPost), Brevo, Loops, Mailchimp Transactional, MailerSend, Mailgun, Mailjet, Mailtrap, Plunk, Postmark, Resend, SendGrid and SMTP2GO
Best example, Mailtrap: mailtrap.io/pricing

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