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Head to head · Email send · October 2026 research run

Cloudflare Email Service vs MailerSend

MailerSend scores 69.5 (B) on agent readiness against Cloudflare Email Service's 67.3 (B), and leads in 2 of 7 scored categories. Cloudflare Email Service leads on schema & documentation, security & auth and transparency & trust. Both do email send.

Cloudflare Email ServiceCloudflare · HTTP API B67.3/100#212 of 722 MailerSendMailerSend, Inc. · HTTP API B69.5/100#156 of 722

Which one, for what

Cloudflare Email Service B

Good for Teams already on Cloudflare DNS and Workers that want transactional sending and inbound handling in one account at a low unit price.

Ahead on

  • Schema & documentation, 89 against 73
  • Security & auth, 77 against 62
  • Transparency & trust, 76 against 64

Watch for

Email Sending has been in public beta since 16 April 2026. Cloudflare's terms let it remove a beta service at any time, and no SLA was found

MailerSend B

Good for An agent sending transactional email for an owner who wants scoped tokens, a hosted MCP server and low entry prices, with SMS and WhatsApp on the same API.

Ahead on

  • Reliability, 95 against 51

Watch for

No idempotency key documented for POST /v1/email or the bulk endpoint

Score by category

CategoryWeight this runCloudflare Email ServiceMailerSendEdge
Reliability16%205195MailerSend +44
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28973Cloudflare Email Service +16
Agent ergonomics13%16.27269Cloudflare Email Service +3
Security & auth14%17.57762Cloudflare Email Service +15
Payments & pricing10%12.53030even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88183MailerSend +2
Transparency & trust7%8.87664Cloudflare Email Service +12
Negative events≤1500
Total67.3 · B69.5 · B

Facts side by side

FactCloudflare Email ServiceMailerSend
KindHTTP APIHTTP API
VendorCloudflareMailerSend, Inc.
Hosted endpointhttps://api.cloudflare.com/client/v4https://api.mailersend.com/v1
TransportsHTTPHTTP, Streamable HTTP
AuthAPI keyOAuth or key
PricingPay per useFreemium
Price for email sendnot published$4 per month (plan)
x402nono
LicenceProprietary service under Cloudflare's Self-Serve Subscription Agreement and Developer Platform service-specific terms. The official cloudflare SDK on npm is Apache-2.0Proprietary service under MailerSend's terms of use. The SDKs and the CLI on GitHub are MIT
Tools exposednone127
Read-only variant documentednono
llms.txtyesyes
Last release2026-09-252026-09-29
Terms last updated2025-09-122026-10-05
Privacy policy last updatedno date given2026-09-17
Customer content may train modelsnot found in the textyes
Terms restrict automated accessyesnot found in the text
Terms restrict benchmarkingnot found in the textnot found in the text
Terms or service can change without noticeyesyes
Arbitration or class-action waiveryesyes
Popularity3.8M npm/wk, 364k PyPI/wk175 stars, 128k npm/wk, 15k PyPI/wk

Verdicts

Cloudflare Email Service

Cloudflare API tokens can be limited to sending, given an expiry and restricted by IP address, and a public OpenAPI file covers 29 Email Sending operations. Sending is still in beta, with no SLA, no idempotency key and no published daily quota, and it needs a domain on Cloudflare DNS and the Workers Paid plan.

MailerSend

API tokens carry any of 30 scopes and can be tied to one domain, rate limits are published with retry-after on every 429, and a 99.5 per cent SLA starts on the $35 Starter plan. Sends take no idempotency key, the Free plan allows 100 API requests a day, and the terms permit changes without notice.

Before you call either

Cloudflare Email Service

  1. POST to https://api.cloudflare.com/client/v4/accounts/{account_id}/email/sending/send with Authorization: Bearer <token>. The body needs to, from, subject and one of html or text
  2. Don't retry a timed-out send blindly. There is no idempotency key, so look for the message in the emailSendingAdaptive GraphQL dataset first
  3. On 429 (code 10004) wait for the retry-after header. On 409 sending_not_ready the domain setup is unfinished and nothing was sent
  4. Read result.delivered, result.queued and result.permanent_bounces in the response. A 200 does not mean every recipient was accepted
  5. Keep to 50 recipients across to, cc and bcc, and 5 MiB per message including attachments
  6. For SMTP use smtp.mx.cloudflare.net on port 465 with implicit TLS, username api_token and the API token as password. Port 587 is not supported
  7. By default one suppressed recipient fails the whole send. Turn on Drop suppressed recipients for the domain to send to the rest

MailerSend

  1. Send Authorization: Bearer <token> to https://api.mailersend.com/v1 and ask for a token with only the scopes the task needs, such as email_full and activity_read
  2. Read the message id from the x-message-id response header. POST /v1/email answers 202 with an empty body
  3. Check for a sent message before retrying a send. No idempotency key exists, so a blind retry can deliver twice
  4. On a 429 wait the seconds in retry-after. Call GET /v1/api-quota, which isn't counted, to see the daily quota left
  5. Use POST /v1/bulk-email for batches of up to 500 emails. It isn't on the Free plan and takes 10 to 60 requests a minute by plan

Questions

Which is better for AI agents, Cloudflare Email Service or MailerSend?

MailerSend scores 69.5 (B) on agent readiness against Cloudflare Email Service's 67.3 (B), and leads in 2 of 7 scored categories. Cloudflare Email Service leads on schema & documentation, security & auth and transparency & trust.

Do Cloudflare Email Service and MailerSend need an API key?

Cloudflare Email Service needs an API key. MailerSend takes an API key or an OAuth sign-in.

Can an agent call Cloudflare Email Service and MailerSend without installing anything?

Yes. Cloudflare Email Service has a hosted endpoint at https://api.cloudflare.com/client/v4 and MailerSend at https://api.mailersend.com/v1.

Other comparisons with Cloudflare Email Service or MailerSend

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