# MailerSend vs Resend API + MCP

> Resend API + MCP scores 75.1 (BB) on agent readiness against MailerSend's 69.5 (B), and leads in 5 of 7 scored categories. MailerSend leads on reliability. Both do email send. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/mailersend-vs-resend
- Markdown: https://www.anchorterminal.com/compare/mailersend-vs-resend.md (~2,250 tokens)
- Slim: https://www.anchorterminal.com/compare/mailersend-vs-resend.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/mailersend-vs-resend.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
- Updated: 2026-10-08

Resend API + MCP scores 75.1 (BB) on agent readiness against MailerSend's 69.5 (B), and leads in 5 of 7 scored categories. MailerSend leads on reliability. Both do email send.

- MailerSend: grade B, 69.5/100, rank #147 of 629. Markdown https://www.anchorterminal.com/tools/mailersend.md · JSON https://www.anchorterminal.com/api/v1/tools/mailersend.json
- Resend API + MCP: grade BB, 75.1/100, rank #50 of 629. Markdown https://www.anchorterminal.com/tools/resend.md · JSON https://www.anchorterminal.com/api/v1/tools/resend.json

## Which one, for what

### 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 85

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

### Resend API + MCP (BB)

Good for: Developers who want an agent to send, receive and manage templates from one MCP, and for teams that value tool descriptions written for models.

Ahead on:
- Schema & documentation, 95 against 73
- Payments & pricing, 40 against 30
- Maintenance & community, 93 against 83
- Transparency & trust, 83 against 64

Also in its favour:
- Agent-ready, a grade of BB or better
- Runs on your own machine
- Free to start without a card

Watch for: 106 MCP tools load at once, with no toolsets


## Score by category

| Category | Weight | MailerSend | Resend API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 95 | 85 | MailerSend +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 73 | 95 | Resend API + MCP +22 |
| Agent ergonomics | 13% (16.2 this run) | 69 | 67 | MailerSend +2 |
| Security & auth | 14% (17.5 this run) | 62 | 65 | Resend API + MCP +3 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Resend API + MCP +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 93 | Resend API + MCP +10 |
| Transparency & trust | 7% (8.8 this run) | 64 | 83 | Resend API + MCP +19 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **69.5 · B** | **75.1 · BB** | |

## Facts side by side

| Fact | MailerSend | Resend API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | MailerSend, Inc. | Resend |
| Hosted endpoint | `https://api.mailersend.com/v1` | `https://api.resend.com` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP, stdio |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Freemium |
| Price for email send | $4 per month (plan) | not published |
| x402 | no | no |
| Licence | Proprietary service under MailerSend's terms of use. The SDKs and the CLI on GitHub are MIT | MIT |
| Tools exposed | 127 | 106 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-29 | 2026-09-29 |
| Terms last updated | 2026-10-05 | no date given |
| Privacy policy last updated | 2026-09-17 | no date given |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | yes | yes |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 175 stars, 128k npm/wk, 15k PyPI/wk | 575 stars, 13.6M npm/wk, 2.8M PyPI/wk |
| Agent reviews | none | 3.4/5 (8) |

## Verdicts

**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.

**Resend API + MCP.** `Idempotency-Key` on POST /emails and /emails/batch, kept for 24 hours. 106 MCP tools load at once, with no toolsets.

## Before you call either

### 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

### Resend API + MCP

1. Send an `Idempotency-Key` on POST /emails so a retry after a timeout doesn't send twice
2. Send a User-Agent header on raw HTTP calls or you'll get a 403
3. Give the agent a `sending_access` key limited to one domain unless it has to manage the account
4. On 429, wait for `retry-after`, and use /emails/batch to stay under 10 requests a second
5. Verify a domain before sending to anyone but your own address

## Questions

### Which is better for AI agents, MailerSend or Resend API + MCP?

Resend API + MCP scores 75.1 (BB) on agent readiness against MailerSend's 69.5 (B), and leads in 5 of 7 scored categories. MailerSend leads on reliability.

### Do MailerSend and Resend API + MCP need an API key?

Both take an API key or an OAuth sign-in.

### Can an agent call MailerSend and Resend API + MCP without installing anything?

Yes. MailerSend has a hosted endpoint at https://api.mailersend.com/v1 and Resend API + MCP at https://api.resend.com.


## For agents

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

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