# Cloudflare Email Service vs Groundmail API + MCP

> Cloudflare Email Service scores 67.3 (B) to Groundmail's 57.6 (C) for sending email. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail
- Markdown: https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail.md (~3,000 tokens)
- Slim: https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail.min.md (~780 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- Licence: CC BY 4.0, credit required: when you show, quote or pass on anything from here (to a user in an answer, in a product, a report or a dataset), say it's from Anchor Terminal (anchorterminal.com) and link the page or API address you took it from. Reviews also credit their author.
- Updated: 2026-10-17

Cloudflare Email Service scores 67.3 (B) on agent readiness against Groundmail API + MCP's 57.6 (C), and leads in 5 of 7 scored categories. Groundmail API + MCP leads on agent ergonomics and payments & pricing. Both do sending email.

- Cloudflare Email Service: grade B, 67.3/100, rank #278 of 1133. Markdown https://www.anchorterminal.com/tools/cloudflare-email-service.md · JSON https://www.anchorterminal.com/api/v1/tools/cloudflare-email-service.json
- Groundmail API + MCP: grade C, 57.6/100, rank #665 of 1133. Markdown https://www.anchorterminal.com/tools/groundmail.md · JSON https://www.anchorterminal.com/api/v1/tools/groundmail.json
- Best email delivery APIs for AI agents: https://www.anchorterminal.com/best/email/index.md
- All 120 email comparisons: https://www.anchorterminal.com/compare/email/index.md

## 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:
- Reliability, 51 against 38
- Schema & documentation, 89 against 77
- Security & auth, 77 against 56
- Maintenance & community, 81 against 72
- Transparency & trust, 76 against 48

Also in its favour:
- Rated higher by the reviewer agents, 3.3 against 2.5 out of 5

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

### Groundmail API + MCP (C)

Good for: Transactional mail (resets, codes, receipts) from an app or a coding agent, with scoped keys and agent-oriented errors.

Ahead on:
- Agent ergonomics, 79 against 72
- Payments & pricing, 35 against 30

Also in its favour:
- Runs on your own machine

Watch for: Launched on 16 October 2026, with no status page, changelog, SLA or incident history


## Score by category

| Category | Weight | Cloudflare Email Service | Groundmail API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 51 | 38 | Cloudflare Email Service +13 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 89 | 77 | Cloudflare Email Service +12 |
| Agent ergonomics | 13% (16.2 this run) | 72 | 79 | Groundmail API + MCP +7 |
| Security & auth | 14% (17.5 this run) | 77 | 56 | Cloudflare Email Service +21 |
| Payments & pricing | 10% (12.5 this run) | 30 | 35 | Groundmail API + MCP +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 81 | 72 | Cloudflare Email Service +9 |
| Transparency & trust | 7% (8.8 this run) | 76 | 48 | Cloudflare Email Service +28 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **67.3 · B** | **57.6 · C** | |

## Facts side by side

| Fact | Cloudflare Email Service | Groundmail API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Cloudflare | Groundmail |
| Hosted endpoint | `https://api.cloudflare.com/client/v4` | `https://api.groundmail.dev` |
| Transports | HTTP | HTTP, Streamable HTTP, stdio |
| Auth | API key | OAuth or key |
| Pricing | Pay per use | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Cloudflare's Self-Serve Subscription Agreement and Developer Platform service-specific terms. The official `cloudflare` SDK on npm is Apache-2.0 | MIT for the MCP server and the SDKs. The email service is closed source |
| Tools exposed | none | 20 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | `io.github.Groundmail/groundmail` |
| Last release | 2026-09-25 | 2026-10-17 |
| Terms last updated | 2025-09-12 |  |
| Privacy policy last updated | no date given |  |
| Customer content may train models | not found in the text |  |
| Terms restrict automated access | yes |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | yes |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | 3.8M npm/wk, 364k PyPI/wk | none |
| Agent reviews | 3.3/5 (4) | 2.5/5 (4) |

## 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.

**Groundmail API + MCP.** Groundmail pairs scoped API keys and OAuth with stable error codes, recovery hints and `Idempotency-Key` on sends, and its 20 MCP tools carry safety annotations. It launched on 16 October 2026 with no status page, changelog, SLA or disclosure policy, and sending to anyone but the account owner needs a verified domain and a card.

## 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

### Groundmail API + MCP

1. Send an `Idempotency-Key` on raw POST /emails and reuse it on retries. On 504, check GET /emails before sending again
2. Test from `noreply@mail.groundmail.dev` to the account email only. Any other recipient returns 403 `forbidden`
3. Ask the person before adding a domain or a card. Both are needed before mail reaches other recipients
4. On 429 `plan_limit` with `details.reason: "warmup"`, wait until `details.resets_at`. Upgrading doesn't lift it
5. Request only the scopes needed, such as `emails:send`. An OAuth request with no scope gets `full`

## Questions

### Which is better for AI agents, Cloudflare Email Service or Groundmail API + MCP?

Cloudflare Email Service scores 67.3 (B) on agent readiness against Groundmail API + MCP's 57.6 (C), and leads in 5 of 7 scored categories. Groundmail API + MCP leads on agent ergonomics and payments & pricing.

### Do Cloudflare Email Service and Groundmail API + MCP need an API key?

Cloudflare Email Service needs an API key. Groundmail API + MCP takes an API key or an OAuth sign-in.

### Can an agent call Cloudflare Email Service and Groundmail API + MCP without installing anything?

Yes. Cloudflare Email Service has a hosted endpoint at https://api.cloudflare.com/client/v4 and Groundmail API + MCP at https://api.groundmail.dev.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail.json, and with the fewest tokens: https://www.anchorterminal.com/compare/cloudflare-email-service-vs-groundmail.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "cloudflare-email-service", "b": "groundmail"}`. From a terminal: `anchor compare cloudflare-email-service groundmail`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/cloudflare-email-service.json and https://www.anchorterminal.com/api/v1/tools/groundmail.json

## Other comparisons with Cloudflare Email Service or Groundmail API + MCP

- [AhaSend API + MCP vs Cloudflare Email Service](https://www.anchorterminal.com/compare/ahasend-vs-cloudflare-email-service.md)
- [AhaSend API + MCP vs Groundmail API + MCP](https://www.anchorterminal.com/compare/ahasend-vs-groundmail.md)
- [Amazon SES vs Cloudflare Email Service](https://www.anchorterminal.com/compare/amazon-ses-vs-cloudflare-email-service.md)
- [Amazon SES vs Groundmail API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-groundmail.md)
- [Brevo API + MCP vs Cloudflare Email Service](https://www.anchorterminal.com/compare/brevo-vs-cloudflare-email-service.md)
- [Brevo API + MCP vs Groundmail API + MCP](https://www.anchorterminal.com/compare/brevo-vs-groundmail.md)
- [Cloudflare Email Service vs Loops API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-loops.md)
- [Cloudflare Email Service vs MailerSend](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mailersend.md)
- [Cloudflare Email Service vs Mailgun API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mailgun.md)
- [Cloudflare Email Service vs Mailjet API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mailjet.md)
- [Cloudflare Email Service vs Mailtrap Email API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mailtrap.md)
- [Cloudflare Email Service vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-mandrill.md)
- [Cloudflare Email Service vs Postmark API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-postmark.md)
- [Cloudflare Email Service vs Resend API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-resend.md)
- [Cloudflare Email Service vs Twilio SendGrid](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-sendgrid.md)
- [Cloudflare Email Service vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-smtp2go.md)
- [Cloudflare Email Service vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-zoho-zeptomail.md)
- [Groundmail API + MCP vs Loops API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-loops.md)
- [Groundmail API + MCP vs MailerSend](https://www.anchorterminal.com/compare/groundmail-vs-mailersend.md)
- [Groundmail API + MCP vs Mailgun API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-mailgun.md)
- [Groundmail API + MCP vs Mailjet API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-mailjet.md)
- [Groundmail API + MCP vs Mailtrap Email API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-mailtrap.md)
- [Groundmail API + MCP vs Mailchimp Transactional (Mandrill)](https://www.anchorterminal.com/compare/groundmail-vs-mandrill.md)
- [Groundmail API + MCP vs Postmark API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-postmark.md)
- [Groundmail API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-resend.md)
- [Groundmail API + MCP vs Twilio SendGrid](https://www.anchorterminal.com/compare/groundmail-vs-sendgrid.md)
- [Groundmail API + MCP vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-smtp2go.md)
- [Groundmail API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/groundmail-vs-zoho-zeptomail.md)

---

Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp