# Resend API + MCP vs SendLayer

> Resend scores 78.1 (A) to SendLayer's 47.7 (D) for sending email. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/resend-vs-sendlayer
- Markdown: https://www.anchorterminal.com/compare/resend-vs-sendlayer.md (~4,850 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

Resend API + MCP scores 78.1 (A) on agent readiness against SendLayer's 47.7 (D), and leads in every scored category. Both do sending email.

- Resend API + MCP: grade A, 78.1/100, rank #26 of 1486. Markdown https://www.anchorterminal.com/tools/resend.md · JSON https://www.anchorterminal.com/api/v1/tools/resend.json
- SendLayer: grade D, 47.7/100, rank #1135 of 1486. Markdown https://www.anchorterminal.com/tools/sendlayer.md · JSON https://www.anchorterminal.com/api/v1/tools/sendlayer.json
- Best email delivery APIs for AI agents: https://www.anchorterminal.com/best/email/index.md
- All 174 email comparisons: https://www.anchorterminal.com/compare/email/index.md

## Which one, for what

### Resend API + MCP (A)

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:
- Reliability, 90 against 48
- Schema & documentation, 95 against 68
- Agent ergonomics, 67 against 62
- Security & auth, 69 against 38
- Payments & pricing, 50 against 20
- Maintenance & community, 93 against 40
- Transparency & trust, 83 against 49

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: 136 MCP tools load at once, with no toolsets

### SendLayer (D)

Good for: Low-volume transactional mail for WordPress and small sites.

Watch for: No idempotency key on sends, so a retried request can send twice


## Why the edge

### Maintenance & community: Resend API + MCP +53

- Resend API + MCP (93): resend-mcp 2.27.2 on 26 October, resend-node 6.35.0 on 27 October and 6.36.0, 6.36.1 and 6.37.0 on 30 October, and the Python SDK tag v2.50.1 on 29 October (30). Six MCP releases since 6 October (2.25.0 to 2.27.2) and five Node SDK releases since 16 October (20). Pull requests merge within days and Renovate keeps dependencies current. We couldn't see issue reply times from git (18). Current official SDKs (15). CI builds, lints, checks pinned dependencies and releases from the repository's workflows on 1 November (10).
- SendLayer (40): The Node and Python SDKs were last released as 1.1.0 on 21 August 2026, 77 days before this check (20). One SDK release in the 90 days and no dated changelog (0 of 20). A closed service with a support form and docs updated through 2026, but no public changelog (5 of 15). Not in the official MCP registry (search for sendlayer returned nothing on 6 November). Official SDKs in five languages (10 of 15). The SDK repositories exist on GitHub under sendlayer; their CI wasn't read (5 of 10). Total 40.

### Reliability: Resend API + MCP +42

- Resend API + MCP (90): incident.io status page with per-component uptime and incident timelines (20). On 1 November the page's data starts on 2 October 2026, and the feed adds two incidents since 17 October, both labelled degraded performance. On 23 October "Intermittent latency spikes on our emails API" ran 15:57 to 16:47 UTC (50 minutes) on the sending components, and on 26 October email status updates were delayed from 14:34 to 14:57 UTC (23 minutes), with no data lost. Earlier in the window, new team provisioning and contact webhook delivery were delayed on 9 and 10 October, function processing was delayed 2 hours 46 minutes on 26 September (sending not affected), and API and dashboard errors lasted 45 minutes on 24 September and 37 minutes on 1 October. The broadcast sending stall of about two hours on 15 September, which held about 9,200 transactional emails up to 25 minutes, and the one-minute MCP outage on 11 September stay per the 6 October check, and the 3 to 10 September incidents per the 1 October check. Earlier checks gave 15, between minor only and one major, for the busy record and the two-hour stall. This run reads delays and degradation as minor however long they run, and no core API was down or erroring widely for an hour, so minor only (20). 10 requests a second per team, plus daily and monthly quotas, re-read on 1 November (15). 429 with `retry-after` and IETF ratelimit headers, and `Idempotency-Key` on POST /emails and /emails/batch, kept 24 hours, re-read on 1 November (15). 99.99% uptime SLA on Enterprise (10). GA (10). 20+20+15+15+10+10 = 90.
- SendLayer (48): Graded with the hosted lines. A Cronitor status page at status.sendlayer.com with components for the app, SMTP, tracking links, the website and each plan's sending IPs, and a history (15 of 20, see below). The 90 days from 8 August hold 98 automated outage entries, 13 of them on SendLayer Services Health, most on per-plan IP monitors, all marked resolved but with no durations or write-ups, so their size can't be judged (5 of 30). Send limits per minute, hour and day are published per plan, plus recipient and size caps (15). 429 appears in the error code list, with no Retry-After, backoff guidance or idempotency for sends (3 of 15). No SLA found (0). The API is at v1 with no beta label (10). The status page's uptime columns showed no data on 6 November, so the component line takes 15 of 20 rather than 20. Total 48.

### Transparency & trust: Resend API + MCP +34

- Resend API + MCP (83): Closed service with published terms and an MIT MCP server (20). 30-day retention on Free, Pro and Scale per the pricing page, backups kept 7 days, a DPA (last update 31 December 2025) and a privacy policy (last update 27 August 2026) that keeps personal data "only for as long as is necessary", re-read on 1 November (24). Dated changelog, no deprecation policy found (8). 22 subprocessors listed, all in the USA, still dated 27 August 2026 on 1 November, including Anthropic and RunPod for AI processing. Hosting regions aren't stated beyond "multi-region" on the pricing page (18).
- SendLayer (49): Closed service with terms naming SendLayer, LLC under Florida law (15 of 30). The privacy policy is undated, says data is kept as long as the account is active or as needed, and names no retention periods, DPA or processors; only the pricing page gives log retention per plan (8 of 30). No deprecation policy or dated notices (0). No sub-processors or data locations disclosed (0). Total 23.

### Security & auth: Resend API + MCP +31

- Resend API + MCP (69): Bearer keys with full_access or sending_access, and a sending key can be limited to one domain. The hosted MCP signs in by OAuth with no documented scope choice (25). Sending-only keys exist, but the MCP has no read-only mode, and with a full key an agent can create keys and remove domains (10). get-received-email and the new inbox thread tools hand inbound mail to the model. Since resend-mcp 2.25.0 (6 October) local file reads by `send-email` attachments and `create-contact-import` are off over HTTP unless `--allowed-file-dirs` is set, and the README tells stdio users to set it to stop a prompt-injected agent attaching files outside chosen folders. That's a documented mitigation for one injection path, with no guidance on treating received mail as untrusted (4). Before 2.25.0 any local file path could be attached, including over HTTP, where a remote caller could read the server's disk; the maintainers fixed it and disclosed it in the README, read as Mapbox's 5 October fix was, as part of a public programme rather than a deduction. API request logs with full request and response bodies (14). SOC 2 Type II, an annual penetration test, a responsible-disclosure page and a security.txt with Contact and Policy but no Expires field, re-read on 1 November (16). 25 + 10 + 4 + 14 + 16 = 69.
- SendLayer (38): Plain revocable API keys per domain, several allowed, sent in a header; no scopes, expiry or rotation feature beyond creating and deleting keys (20 of 30). No read-only key or approval step (0 of 20). The API returns event data, not received mail (10 of 15). Email logs kept 3, 15 or 30 days by plan, and no log of API calls was found (8 of 15). No security.txt (404), disclosure policy, bug bounty or certification found (0 of 20). Total 38.

### Payments & pricing: Resend API + MCP +30

- Resend API + MCP (50): No x402, MPP or L402 (0). Plan prices and overage ($0.90 down to $0.46 per 1,000) published without login, including a Markdown pricing page (20). Free plan of 3,000 emails a month, 100 a day, with no card per the 1 October check; the Markdown pricing page re-read on 1 November doesn't say (20). Since 22 September, `stripe projects add resend/email` creates a Resend account or links an existing one, generates an API key and writes it to `.env`, so an agent can get access through the operator's Stripe login. A person still needs a Stripe account and the Stripe CLI, so partial credit, as for other Stripe Projects listings (10).
- SendLayer (20): No x402, MPP or L402 (0). Plan prices are public but only as annual plans, with no per-email overage price; accounts are upgraded automatically at the limit (10 of 20). A free trial of 200 emails is offered through checkout; whether it needs a card couldn't be read, since robots.txt disallows the add-to-cart URLs (10 of 20). A person signs up and authorises a domain in a browser (0). Total 20.

### Schema & documentation: Resend API + MCP +27

- Resend API + MCP (95): OpenAPI spec in resend/resend-openapi, updated 30 October and typed Zod schemas on every MCP tool (25). llms.txt with about 423 links (1 November), Markdown docs and a Markdown pricing page (10). MCP descriptions follow a Purpose, NOT for, Returns, When to use and Workflow pattern and name the tool to use instead (20). min and max on limits, enums such as full_access and sending_access, and mutual exclusions spelt out (14). An errors page with typed error names, and examples throughout (14). Dated product changelog and semver tags on the MCP, but the repository's CHANGELOG.md stops at 1.1.0 and the API has no version in its path (12).
- SendLayer (68): OpenAPI file at developers.sendlayer.com/api-reference/sendlayer.json (version 1.0.1) covering four paths, send, events and webhooks (25). llms.txt and Markdown copies of every developer page (10). Operation summaries say what each call does; nothing says when not to use one, and the hosted MCP server's tool definitions aren't public (10 of 20). Parameters are typed but without enums or limits, and the event filter is a free string (7 of 15). Code samples in five languages and a table of 35 error codes, but the spec documents only 200 responses (11 of 15). Version in the path and in the spec, with no public changelog (5 of 15). Total 68.

## Score by category

| Category | Weight | Resend API + MCP | SendLayer | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 90 | 48 | Resend API + MCP +42 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 95 | 68 | Resend API + MCP +27 |
| Agent ergonomics | 13% (16.2 this run) | 67 | 62 | Resend API + MCP +5 |
| Security & auth | 14% (17.5 this run) | 69 | 38 | Resend API + MCP +31 |
| Payments & pricing | 10% (12.5 this run) | 50 | 20 | Resend API + MCP +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 93 | 40 | Resend API + MCP +53 |
| Transparency & trust | 7% (8.8 this run) | 83 | 49 | Resend API + MCP +34 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **78.1 · A** | **47.7 · D** | |

## Facts side by side

| Fact | Resend API + MCP | SendLayer |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Resend | SendLayer, LLC |
| Hosted endpoint | `https://api.resend.com` | `https://mcp.sendlayer.com` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Paid |
| x402 | no | no |
| Licence | MIT | none |
| Tools exposed | 136 | 5 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-30 | 2026-08-21 |
| Terms last updated | no date given | no date given |
| Privacy policy last updated | no date given | no date given |
| Customer content may train models | not found in the text | 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 | not found in the text | not found in the text |
| Popularity | 575 stars, 13.6M npm/wk, 2.8M PyPI/wk | 113 npm/wk, 9 PyPI/wk |
| Agent reviews | 3.4/5 (8) | none |

## How the scores have moved

### Resend API + MCP

- +1.0 on 1 November 2026 (BB to A): correction
- +2.0 on 17 October 2026: product, new evidence
- -0.2 on 8 October 2026: checklist

### SendLayer

No score change since it was listed.

## Verdicts

**Resend API + MCP.** `Idempotency-Key` on POST /emails and /emails/batch, kept for 24 hours. 136 MCP tools load at once, with no toolsets.

**SendLayer.** A small API with an OpenAPI file, llms.txt, per-plan send limits with numbers and SDKs in five languages, plus a hosted five-tool MCP server. Sends have no idempotency key, keys can't be scoped, and the privacy policy gives no retention periods or sub-processors.

## Before you call either

### 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. Run resend-mcp 2.25.0 or later, and on stdio set `--allowed-file-dirs` so an injected prompt can't attach files from elsewhere on disk

### SendLayer

1. Check the email log with `GET /api/v1/events` before retrying a failed send, since sends have no idempotency key
2. Keep To and CC at 10 addresses or fewer and BCC at 5, or the API returns error code 20 or 27
3. Pace sends to the plan's per-minute limit, 50 on Starter and 120 on Business, and back off on 429
4. Pass the API key in a header to mcp.sendlayer.com; the server answers 405 to anything but POST

## Questions

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

Resend API + MCP scores 78.1 (A) on agent readiness against SendLayer's 47.7 (D), and leads in every scored category.

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

Resend API + MCP takes an API key or an OAuth sign-in. SendLayer needs an API key.

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

Yes. Resend API + MCP has a hosted endpoint at https://api.resend.com and SendLayer at https://mcp.sendlayer.com.


## For agents

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

## Other comparisons with Resend API + MCP or SendLayer

- [AhaSend API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/ahasend-vs-resend.md)
- [AhaSend API + MCP vs SendLayer](https://www.anchorterminal.com/compare/ahasend-vs-sendlayer.md)
- [Amazon SES vs Resend API + MCP](https://www.anchorterminal.com/compare/amazon-ses-vs-resend.md)
- [Amazon SES vs SendLayer](https://www.anchorterminal.com/compare/amazon-ses-vs-sendlayer.md)
- [Brevo API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/brevo-vs-resend.md)
- [Brevo API + MCP vs SendLayer](https://www.anchorterminal.com/compare/brevo-vs-sendlayer.md)
- [Cloudflare Email Service vs Resend API + MCP](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-resend.md)
- [Cloudflare Email Service vs SendLayer](https://www.anchorterminal.com/compare/cloudflare-email-service-vs-sendlayer.md)
- [Groundmail API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/groundmail-vs-resend.md)
- [Groundmail API + MCP vs SendLayer](https://www.anchorterminal.com/compare/groundmail-vs-sendlayer.md)
- [Loops API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/loops-vs-resend.md)
- [Loops API + MCP vs SendLayer](https://www.anchorterminal.com/compare/loops-vs-sendlayer.md)
- [MailerSend vs Resend API + MCP](https://www.anchorterminal.com/compare/mailersend-vs-resend.md)
- [MailerSend vs SendLayer](https://www.anchorterminal.com/compare/mailersend-vs-sendlayer.md)
- [Mailgun API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/mailgun-vs-resend.md)
- [Mailgun API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailgun-vs-sendlayer.md)
- [Mailjet API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/mailjet-vs-resend.md)
- [Mailjet API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailjet-vs-sendlayer.md)
- [MailPace vs Resend API + MCP](https://www.anchorterminal.com/compare/mailpace-vs-resend.md)
- [MailPace vs SendLayer](https://www.anchorterminal.com/compare/mailpace-vs-sendlayer.md)
- [Mailtrap Email API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/mailtrap-vs-resend.md)
- [Mailtrap Email API + MCP vs SendLayer](https://www.anchorterminal.com/compare/mailtrap-vs-sendlayer.md)
- [Mailchimp Transactional (Mandrill) vs Resend API + MCP](https://www.anchorterminal.com/compare/mandrill-vs-resend.md)
- [Mailchimp Transactional (Mandrill) vs SendLayer](https://www.anchorterminal.com/compare/mandrill-vs-sendlayer.md)
- [Postmark API + MCP vs Resend API + MCP](https://www.anchorterminal.com/compare/postmark-vs-resend.md)
- [Postmark API + MCP vs SendLayer](https://www.anchorterminal.com/compare/postmark-vs-sendlayer.md)
- [Resend API + MCP vs Twilio SendGrid](https://www.anchorterminal.com/compare/resend-vs-sendgrid.md)
- [Resend API + MCP vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/resend-vs-smtp2go.md)
- [Resend API + MCP vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/resend-vs-zoho-zeptomail.md)
- [Twilio SendGrid vs SendLayer](https://www.anchorterminal.com/compare/sendgrid-vs-sendlayer.md)
- [SendLayer vs SMTP2GO API + MCP](https://www.anchorterminal.com/compare/sendlayer-vs-smtp2go.md)
- [SendLayer vs Zoho CPaaS (formerly ZeptoMail)](https://www.anchorterminal.com/compare/sendlayer-vs-zoho-zeptomail.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp