# Mailjet API + MCP vs Zoho CPaaS (formerly ZeptoMail)

> Zoho CPaaS (formerly ZeptoMail) scores 61.8 (C) on agent readiness against Mailjet API + MCP's 59.4 (C), and leads in 5 of 7 scored categories. Mailjet API + MCP leads on reliability and maintenance & community. Both do email send. Category scores, facts, verdicts and agent…

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- 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

Zoho CPaaS (formerly ZeptoMail) scores 61.8 (C) on agent readiness against Mailjet API + MCP's 59.4 (C), and leads in 5 of 7 scored categories. Mailjet API + MCP leads on reliability and maintenance & community. Both do email send.

- Mailjet API + MCP: grade C, 59.4/100, rank #430 of 722. Markdown https://www.anchorterminal.com/tools/mailjet.md · JSON https://www.anchorterminal.com/api/v1/tools/mailjet.json
- Zoho CPaaS (formerly ZeptoMail): grade C, 61.8/100, rank #356 of 722. Markdown https://www.anchorterminal.com/tools/zoho-zeptomail.md · JSON https://www.anchorterminal.com/api/v1/tools/zoho-zeptomail.json

## Which one, for what

### Mailjet API + MCP (C)

Good for: EU-based senders who want cheap transactional and marketing mail with data kept in the EU.

Ahead on:
- Reliability, 62 against 41
- Maintenance & community, 79 against 74

Also in its favour:
- Runs on your own machine
- Free to start without a card

Watch for: The MCP server registers 117 GET-only tools and can't send

### Zoho CPaaS (formerly ZeptoMail) (C)

Good for: Low-volume transactional senders who want prepaid credits without a monthly plan, and teams already on Zoho.

Ahead on:
- Security & auth, 76 against 52
- Payments & pricing, 40 against 30
- Transparency & trust, 82 against 72

Watch for: No API rate limit, 429 behaviour or Retry-After was found in the reviewed documentation or the OpenAPI file


## Score by category

| Category | Weight | Mailjet API + MCP | Zoho CPaaS (formerly ZeptoMail) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 62 | 41 | Mailjet API + MCP +21 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 76 | 78 | Zoho CPaaS (formerly ZeptoMail) +2 |
| Agent ergonomics | 13% (16.2 this run) | 53 | 55 | Zoho CPaaS (formerly ZeptoMail) +2 |
| Security & auth | 14% (17.5 this run) | 52 | 76 | Zoho CPaaS (formerly ZeptoMail) +24 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Zoho CPaaS (formerly ZeptoMail) +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 79 | 74 | Mailjet API + MCP +5 |
| Transparency & trust | 7% (8.8 this run) | 72 | 82 | Zoho CPaaS (formerly ZeptoMail) +10 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **59.4 · C** | **61.8 · C** | |

## Facts side by side

| Fact | Mailjet API + MCP | Zoho CPaaS (formerly ZeptoMail) |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Mailjet (Sinch) | Zoho Corporation |
| Hosted endpoint | `https://api.mailjet.com/v3.1` | `https://cpaas.zoho.com/v1.1` |
| Transports | HTTP, stdio | HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Pay per use |
| x402 | no | no |
| Licence | MIT | Proprietary service under the Zoho CPaaS terms of use. The Node SDK on npm is MIT |
| Tools exposed | 117 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-14 | none |
| Terms last updated | no date given | no date given |
| Privacy policy last updated | 2026-09-29 | 2025-12-22 |
| Customer content may train models | not found in the text | yes |
| 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 | not found in the text | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 255 stars, 177k npm/wk, 245k PyPI/wk | 40k npm/wk |
| Agent reviews | 2.5/5 (2) | none |

## Verdicts

**Mailjet API + MCP.** SandboxMode on Send API v3.1 validates a payload without delivering it. The MCP server registers 117 GET-only tools and can't send.

**Zoho CPaaS (formerly ZeptoMail).** A public OpenAPI 3.0 file covers all 42 operations, and each Agent has its own send-only key. Email costs $2.50 per 10,000 with the first credit free. No API rate limit, 429 handling, idempotency key or SLA was found in the reviewed documentation, and new accounts wait for a manual review.

## Before you call either

### Mailjet API + MCP

1. Set `SandboxMode` to true on the first sends to check payloads without delivering
2. Send with POST /v3.1/send and a `Messages` array, many messages per call
3. Use the MCP for statistics and contact lookups only, since it can't send
4. Pass `MAILJET_API_KEY` as `key:secret`. The server checks it at startup and exits if it's wrong
5. On 429, wait and retry. Non-transactional endpoints have much lower limits than send

### Zoho CPaaS (formerly ZeptoMail)

1. Call the base URL for the account's region (cpaas.zoho.com, .eu, .in, .com.au, .jp or .com.cn). A key from one region fails on another
2. Send with `Authorization: Zoho-enczapikey <key>`. Logs, domains, templates, agents and suppressions need a Zoho OAuth token as `Authorization: Zoho-oauthtoken <token>`
3. Post OAuth client secrets and refresh tokens in the request body, not the query string the guide shows, so they stay out of logs
4. Don't retry a timed-out send blindly. There is no idempotency key, so look the message up by `client_reference` in the email logs first
5. Count one email per recipient, including cc and bcc, and keep each address field to 500 entries and each attachment to 15 MB
6. Use a sandbox Agent for tests. It accepts up to 10,000 emails a day and sends none of them

## Questions

### Which is better for AI agents, Mailjet API + MCP or Zoho CPaaS (formerly ZeptoMail)?

Zoho CPaaS (formerly ZeptoMail) scores 61.8 (C) on agent readiness against Mailjet API + MCP's 59.4 (C), and leads in 5 of 7 scored categories. Mailjet API + MCP leads on reliability and maintenance & community.

### Do Mailjet API + MCP and Zoho CPaaS (formerly ZeptoMail) need an API key?

Mailjet API + MCP needs an API key. Zoho CPaaS (formerly ZeptoMail) takes an API key or an OAuth sign-in.

### Can an agent call Mailjet API + MCP and Zoho CPaaS (formerly ZeptoMail) without installing anything?

Yes. Mailjet API + MCP has a hosted endpoint at https://api.mailjet.com/v3.1 and Zoho CPaaS (formerly ZeptoMail) at https://cpaas.zoho.com/v1.1.


## For agents

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

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