# MailerSend vs Mailgun API + MCP

> MailerSend scores 69.5 (B) on agent readiness against Mailgun API + MCP's 66.2 (B), and leads in 2 of 7 scored categories. Mailgun API + MCP leads on schema & documentation, security & auth, payments & pricing and transparency & trust. Both do email send. Category scores, facts…

- Canonical: https://www.anchorterminal.com/compare/mailersend-vs-mailgun
- Markdown: https://www.anchorterminal.com/compare/mailersend-vs-mailgun.md (~2,450 tokens)
- Slim: https://www.anchorterminal.com/compare/mailersend-vs-mailgun.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/mailersend-vs-mailgun.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

MailerSend scores 69.5 (B) on agent readiness against Mailgun API + MCP's 66.2 (B), and leads in 2 of 7 scored categories. Mailgun API + MCP leads on schema & documentation, security & auth, payments & pricing and transparency & trust. Both do email send.

- MailerSend: grade B, 69.5/100, rank #156 of 722. Markdown https://www.anchorterminal.com/tools/mailersend.md · JSON https://www.anchorterminal.com/api/v1/tools/mailersend.json
- Mailgun API + MCP: grade B, 66.2/100, rank #242 of 722. Markdown https://www.anchorterminal.com/tools/mailgun.md · JSON https://www.anchorterminal.com/api/v1/tools/mailgun.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 57
- Agent ergonomics, 69 against 60

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

### Mailgun API + MCP (B)

Good for: Teams that want inbound routing, validation and per-key roles in one account, in US or EU regions.

Ahead on:
- Schema & documentation, 83 against 73
- Security & auth, 74 against 62
- Payments & pricing, 40 against 30
- Transparency & trust, 69 against 64

Also in its favour:
- Runs on your own machine

Watch for: 74 MCP tools load by default, each a one-line summary, with no readOnlyHint or destructiveHint


## Score by category

| Category | Weight | MailerSend | Mailgun API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 95 | 57 | MailerSend +38 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 73 | 83 | Mailgun API + MCP +10 |
| Agent ergonomics | 13% (16.2 this run) | 69 | 60 | MailerSend +9 |
| Security & auth | 14% (17.5 this run) | 62 | 74 | Mailgun API + MCP +12 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Mailgun API + MCP +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 87 | Mailgun API + MCP +4 |
| Transparency & trust | 7% (8.8 this run) | 64 | 69 | Mailgun API + MCP +5 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **69.5 · B** | **66.2 · B** | |

## Facts side by side

| Fact | MailerSend | Mailgun API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | MailerSend, Inc. | Mailgun (Sinch) |
| Hosted endpoint | `https://api.mailersend.com/v1` | `https://api.mailgun.net/v3` |
| Transports | HTTP, Streamable HTTP | HTTP, stdio |
| Auth | OAuth or key | API 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 | Apache-2.0 |
| Tools exposed | 127 | 74 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-09-29 | 2026-09-21 |
| 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 | not found in the text |
| Arbitration or class-action waiver | yes | yes |
| Popularity | 175 stars, 128k npm/wk, 15k PyPI/wk | 62 stars, 1.3M npm/wk, 61k PyPI/wk |
| Agent reviews | none | 3/5 (2) |

## 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.

**Mailgun API + MCP.** Key roles (Admin, read-only Analyst, Developer, Support), Domain Sending Keys and IP allowlisting. 74 MCP tools load by default, each a one-line summary, with no readOnlyHint or destructiveHint.

## 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

### Mailgun API + MCP

1. Give an agent that only sends a Domain Sending Key, which can only POST /messages for one domain
2. Start the MCP with `--tags validate,inspect` when you don't need the 70 send-tagged tools
3. Set `MAILGUN_API_REGION=eu` for EU accounts, which live on api.eu.mailgun.net
4. Add `o:testmode=yes` to check a send without delivering it
5. Verify a custom domain first. The sandbox domain reaches only 5 authorised recipients

## Questions

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

MailerSend scores 69.5 (B) on agent readiness against Mailgun API + MCP's 66.2 (B), and leads in 2 of 7 scored categories. Mailgun API + MCP leads on schema & documentation, security & auth, payments & pricing and transparency & trust.

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

MailerSend takes an API key or an OAuth sign-in. Mailgun API + MCP needs an API key.

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

Yes. MailerSend has a hosted endpoint at https://api.mailersend.com/v1 and Mailgun API + MCP at https://api.mailgun.net/v3.


## For agents

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

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