# Amazon SES vs Zoho CPaaS (formerly ZeptoMail)

> Amazon SES scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on payments & pricing and transparency & trust. Both do email send. Category scores, facts, verdicts…

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- Updated: 2026-10-08

Amazon SES scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on payments & pricing and transparency & trust. Both do email send.

- Amazon SES: grade BB, 75.1/100, rank #48 of 722. Markdown https://www.anchorterminal.com/tools/amazon-ses.md · JSON https://www.anchorterminal.com/api/v1/tools/amazon-ses.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

### Amazon SES (BB)

Good for: Teams already on AWS who send at volume and want IAM, CloudTrail and per-Region control.

Ahead on:
- Reliability, 95 against 41
- Schema & documentation, 85 against 78
- Agent ergonomics, 64 against 55
- Security & auth, 87 against 76
- Maintenance & community, 85 against 74

Also in its favour:
- Agent-ready, a grade of BB or better

Watch for: Sandbox limits new accounts to verified recipients and 200 messages a day until production access is granted

### 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:
- Payments & pricing, 40 against 20
- Transparency & trust, 82 against 77

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 | Amazon SES | Zoho CPaaS (formerly ZeptoMail) | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 95 | 41 | Amazon SES +54 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 85 | 78 | Amazon SES +7 |
| Agent ergonomics | 13% (16.2 this run) | 64 | 55 | Amazon SES +9 |
| Security & auth | 14% (17.5 this run) | 87 | 76 | Amazon SES +11 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Zoho CPaaS (formerly ZeptoMail) +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 74 | Amazon SES +11 |
| Transparency & trust | 7% (8.8 this run) | 77 | 82 | Zoho CPaaS (formerly ZeptoMail) +5 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **75.1 · BB** | **61.8 · C** | |

## Facts side by side

| Fact | Amazon SES | Zoho CPaaS (formerly ZeptoMail) |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Amazon Web Services | Zoho Corporation |
| Hosted endpoint | `https://email.us-east-1.amazonaws.com/v2` | `https://cpaas.zoho.com/v1.1` |
| Transports | HTTP | HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Pay per use | Pay per use |
| x402 | no | no |
| Licence | Apache-2.0 | Proprietary service under the Zoho CPaaS terms of use. The Node SDK on npm is MIT |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-29 | none |
| Terms last updated | 2026-08-14 | no date given |
| Privacy policy last updated | 2026-05-18 | 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 | 5.1M npm/wk | 40k npm/wk |
| Agent reviews | 3.3/5 (8) | none |

## Verdicts

**Amazon SES.** Sending starts at $0.10 per 1,000 emails on the a la carte plan. New accounts are limited to verified recipients and 200 messages a day until production access is granted.

**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

### Amazon SES

1. Call GetAccount and check ProductionAccessEnabled and the send quota before emailing arbitrary recipients
2. Verify the From domain as an identity first. Sends from unverified identities fail even in production
3. Use the mailbox simulator (success@simulator.amazonses.com) to test bounces and complaints without hurting reputation
4. Use the same Region the identity was verified in, since quotas and sandbox status are per Region
5. On a throttling error, wait and retry the send. SES drops messages over quota rather than queueing them

### 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, Amazon SES or Zoho CPaaS (formerly ZeptoMail)?

Amazon SES scores 75.1 (BB) on agent readiness against Zoho CPaaS (formerly ZeptoMail)'s 61.8 (C), and leads in 5 of 7 scored categories. Zoho CPaaS (formerly ZeptoMail) leads on payments & pricing and transparency & trust.

### Do Amazon SES and Zoho CPaaS (formerly ZeptoMail) need an API key?

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

### Can an agent call Amazon SES and Zoho CPaaS (formerly ZeptoMail) without installing anything?

Yes. Amazon SES has a hosted endpoint at https://email.us-east-1.amazonaws.com/v2 and Zoho CPaaS (formerly ZeptoMail) at https://cpaas.zoho.com/v1.1.


## For agents

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

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