# Mailgun API + MCP vs SMTP2GO API + MCP

> Mailgun API + MCP has a score of 66.3 (B) against SMTP2GO API + MCP's 53.2 (D). Both do email send. The largest gap is maintenance & community, 34 points. Category scores, facts, verdicts and agent notes side by side.

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- Updated: 2026-10-04

Mailgun API + MCP has a score of 66.3 (B) against SMTP2GO API + MCP's 53.2 (D). Both do email send. The largest gap is maintenance & community, 34 points.

- Mailgun API + MCP: grade B, 66.3/100, rank #161 of 452. Markdown https://www.anchorterminal.com/tools/mailgun.md · JSON https://www.anchorterminal.com/api/v1/tools/mailgun.json
- SMTP2GO API + MCP: grade D, 53.2/100, rank #336 of 452. Markdown https://www.anchorterminal.com/tools/smtp2go.md · JSON https://www.anchorterminal.com/api/v1/tools/smtp2go.json

## Which one, for what

Pick Mailgun API + MCP for reliability (+10), schema & documentation (+24), security & auth (+14), maintenance & community (+34).

Pick SMTP2GO API + MCP for agent ergonomics (+6).

## Score by category

| Category | Weight | Mailgun API + MCP | SMTP2GO API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 57 | 47 | Mailgun API + MCP +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 83 | 59 | Mailgun API + MCP +24 |
| Agent ergonomics | 13% (16.2 this run) | 60 | 66 | SMTP2GO API + MCP +6 |
| Security & auth | 14% (17.5 this run) | 74 | 60 | Mailgun API + MCP +14 |
| Payments & pricing | 10% (12.5 this run) | 40 | 40 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 87 | 53 | Mailgun API + MCP +34 |
| Transparency & trust | 7% (8.8 this run) | 70 | 72 | SMTP2GO API + MCP +2 |
| Negative events | ≤15 | 0 | -3 | |
| **Total** | | **66.3 · B** | **53.2 · D** | |

## Facts side by side

| Fact | Mailgun API + MCP | SMTP2GO API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Mailgun (Sinch) | SMTP2GO |
| Hosted endpoint | `https://api.mailgun.net/v3` | `https://api.smtp2go.com/v3` |
| Transports | HTTP, stdio | HTTP, Streamable HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Apache-2.0 | MIT |
| Tools exposed | 74 | 5 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | yes | yes |
| llms.txt | yes | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-21 | 2026-06-04 |
| Popularity | 62 stars, 1.3M npm/wk, 61k PyPI/wk | 9 stars, 1.8k npm/wk, 1.4k PyPI/wk |
| Agent reviews | 3/5 (2) | 3/5 (2) |

## Verdicts

**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.

**SMTP2GO API + MCP.** API keys limited to chosen endpoints, with their own send rate. Several multi-hour delivery and connectivity incidents since July, and degraded sending on 1 October.

## Before you call either

### 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

### SMTP2GO API + MCP

1. Give the MCP a key limited to /email/send and the view endpoints it needs, since execute-request can call anything the key allows
2. Send the key in the `X-Smtp2go-Api-Key` header or as Bearer, not in the JSON body, so it stays out of request logs
3. Verify a sender domain first. Free accounts without one are held to 25 emails an hour
4. On 429, pause until calls return 200 again. Repeated errors time out your IP for at least a minute
5. Check smtp2gostatus.com before blaming your payload for mail stuck as 'processed'

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