Head to head · Agent inboxes · October 2026 research run

Cherami vs Clawpost

Cherami scores 58.6 (C) on agent readiness against Clawpost's 36.8 (F), and leads in 6 of 7 scored categories. Clawpost leads on payments & pricing. Both do agent inboxes.

Best email inbox APIs for AI agents · All 66 inboxes comparisons

Which one, for what

Cherami C

Best for A single developer or small team giving an agent a free, separate address for low-volume recurring correspondence such as supplier replies, project updates and agent-to-agent handoffs.

Ahead on

  • Reliability, 40 against 8
  • Schema & documentation, 85 against 54
  • Agent ergonomics, 80 against 53
  • Maintenance & community, 74 against 2
  • Transparency & trust, 56 against 32

Also in its favour

  • A hosted endpoint, with nothing to install
  • Free to start without a card

Watch for

No status page, SLA or public changelog, so the webhooks API carries no release date

Clawpost F

Best for A developer who wants an agent inbox on their own domain and Cloudflare account with a default approval gate.

Ahead on

  • Payments & pricing, 60 against 35

Also in its favour

  • Open source

Watch for

One shared API key grants every REST and MCP operation; no scopes or read-only key

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Maintenance & community Cherami +72

Cherami 74

TypeScript and Python SDKs 0.2.0 were released on 9 October 2026 (release commits 6b7dbde and 9e9a299, adding Trash listing and restore operations), 26 days before the check (30). In the 90 days from 6 August each of the two SDKs released 0.1.0 (3 and 4 October), 0.1.1 (8 October, README and version only) and 0.2.0, all distinct dated release commits. SDK releases count half on this line, so the six make three (20). The webhooks API in the live contract has no dated entry. Closed service with support by email at hello@cherami.to and a feedback tool in the API. No public changelog, the GitHub repositories carry no issues we could read, and we didn't test support (6 of 15). In the official MCP registry as io.github.cherami-mail/cherami-mcp, a GitHub-verified namespace, per the 5 October check, with official SDKs, which lag the live contract by its 15 newer operations (15). Both SDKs are generated from the OpenAPI contract and have a typecheck script, but neither repository has CI workflows or tests (3 of 10).

Clawpost 2

The last commit was on 1 April 2026, 219 days before this check (0). No releases or commits in the 90 days from 8 August (0). Issue and pull request activity couldn't be read through GitHub's API that day (0, unchecked). Not in the official MCP registry and no published package (0). Dependencies such as agents ^0.0.74 and the MCP SDK ^1.12.1 date from early 2026, and there's no CI (2 of 10). Total 2.

Reliability Cherami +32

Cherami 40

Hosted lines. No status page. status.cherami.to doesn't resolve and cherami.to/status returns 404 on 4 November (0). With no history to read, the incident record gets 5. Signup discovery (10 per IP an hour), phrase redemption and browser approvals (10 per IP per 15 minutes) and the sending allowance (25 recipients per rolling 24 hours) are published with numbers, but no general request limit for reading or listing mail is stated (10 of 15). 429s carry Retry-After, the allowance error returns sufficient_capacity_at, and a retry table per operation sits beside idempotency keys on every write that sends or creates (15). The deployment guide says service commitments are by request and none is published (0). The API is /v1 with contract version 1.0.0 and no beta label on the HTTP or MCP surface (10).

Clawpost 8

Graded with the lines for self-hosted software, since each deployer runs their own Worker. No published package; it deploys from the repository with a Deploy to Cloudflare button, Bun and Wrangler, and states the Cloudflare products it needs (8 of 20). No CI workflow or test suite in the repository (0). Open issues couldn't be read, because GitHub's API refused our requests for its rate limit, so the line scores absent (0, unchecked). No tags, releases or changelog; package.json says 0.1.0 (0). Pre-1.0 (0). Total 8.

Schema & documentation Cherami +31

Cherami 85

OpenAPI 3.1.1 at cherami.to/openapi.json with 54 operations on 4 November, webhooks included (25). llms.txt, the whole documentation in llms-full.txt and a Markdown twin of every page (10). The MCP docs list 42 tools with a line on when to use each, and the API reference describes every operation, though a few tools state only the purpose. The 5 October reading of the live tool definitions came from a request to the MCP endpoint and is no longer used (16 of 20). Inputs in the contract use format: uuid, patterns, length and item limits, required fields and additionalProperties: false, with enums (14 of 15). An error catalogue with a recovery step for each code, curl, TypeScript and Python examples and two cookbooks (15). Versioned /v1 path and contract version 1.0.0, but no public changelog (cherami.to/changelog answers 404), so the webhooks API added after 9 October carries no date (5 of 15).

Clawpost 54

All 21 MCP tools take typed zod inputs, which the MCP SDK publishes as JSON Schema (25). SKILL.md and AGENTS.md give agent-readable setup in Markdown; no llms.txt (5 of 10). Descriptions are one line each, such as Send an email, with parameter descriptions but no when-not-to-use (8 of 20). Inputs are typed with defaults for limit and offset, but recipients are a comma-separated string and direction isn't an enum in the schema read (9 of 15). The README has request examples and a REST route table; error responses aren't documented (7 of 15). No versioning or changelog (0). Total 54.

Agent ergonomics Cherami +27

Cherami 80

The MCP docs list 42 tools, more than 30, with no toolset or read-only subset to load fewer (5). Lists take limit (1 to 100) and opaque cursors, with search, label, date and participant filters, compact list bodies and attachments read in chunks (20). Errors carry a stable error.code, a message and recovery guidance per code (20). Idempotency keys on inbox, draft and message creation and on every send, honoured for 24 hours, and a draft that can be sent only once. The tool annotations recorded on 5 October came from a request to the MCP endpoint and aren't relied on; the documented keys meet the line for the API (20). Official SDKs for TypeScript and Python, and a send needs only inbox_id, to, subject and text (15).

Clawpost 53

21 tools, the 11 to 30 band (15 of 25). List and search tools take limit, offset and filters by direction, sender, label and archive state (20). Error shapes aren't documented; the code returns JSON errors (8 of 20). No idempotency key for sends and no readOnlyHint or destructiveHint annotations; drafts give a review step (3 of 20). Archived mail is excluded by default and the CLI has a --json mode, but there's no SDK beyond the CLI (7 of 15). Total 53.

Payments & pricing Clawpost +25

Cherami 35

No x402, MPP or L402 (0). The service is free with its allowances published without a login, 2 inboxes and 25 recipient-deliveries a day. Anything beyond that is by request with no published price (15 of 20). No card and no paid tier (20). An agent can't get access alone. A person signs in and approves at cherami.to/claim in a browser, then gives the agent a one-use phrase, or approves an OAuth connection (0).

Clawpost 60

Free self-hosted software with nothing to buy from the author, which the rubric scores 20 + 20 + 20. Running it needs the deployer's own Cloudflare Workers Paid plan at $5 a month, which isn't Clawpost's charge. No payment protocol (0 of 40). Total 60.

Transparency & trust Cherami +24

Cherami 56

The service is closed under published terms (effective 9 October 2026). The SDKs and plugin files are MIT, and the MCP server's source isn't public (16 of 30). The privacy policy (effective 9 October 2026) names its providers and gives retention periods (no automatic mail expiry, Trash for seven days, Cloudflare logs up to 7 days, Clerk logs a few days, backups up to 30 days, account deletion within 30 days) and says mail isn't sold or used for advertising. It doesn't address model training, and a DPA is by request (24 of 30). No deprecation policy or dated notices, and the terms allow the service's functions, limits and availability to change and the service to be discontinued with no stated notice period (3 of 20). Cloudflare on its global network, Clerk and Svix in the United States are named, with no guaranteed processing location (15 of 20).

Clawpost 32

The README and SKILL.md say MIT, but no LICENSE file is committed (20 of 30). Self-hosted; the README says mail is stored in the deployer's D1 database with attachments in R2 and sent through Cloudflare Email Service or Resend. No retention or deletion guidance (15 of 30). No deprecation policy (0). No telemetry in the source read; the only outbound calls are to the configured mail provider, Cloudflare's API and the deployer's own webhooks (15 of 20). Total 50.

Score by category

CategoryWeight this runCheramiClawpostEdge
Reliability16%20408Cherami +32
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28554Cherami +31
Agent ergonomics13%16.28053Cherami +27
Security & auth14%17.54642Cherami +4
Payments & pricing10%12.53560Clawpost +25
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.8742Cherami +72
Transparency & trust7%8.85632Cherami +24
Negative events≤1500
TotalC 58.6/100F 36.8/100

Facts side by side

FactCheramiClawpost
KindHTTP APIMCP server
VendorCheramiFrank Harris
Hosted endpointhttps://cherami.to/mcpno (local only)
TransportsHTTP, Streamable HTTPStreamable HTTP, HTTP
AuthOAuth or keyAPI key
PricingFreeFree
x402nono
LicenceProprietary hosted service under Cherami's terms of use. The plugin repository (cherami-mail/cherami-mcp) and the TypeScript and Python SDKs are MIT. The MCP server's own source isn't publicMIT
Tools exposed4221
Read-only variant documentednono
llms.txtyesno
MCP registryio.github.cherami-mail/cherami-mcpnot listed
Last release2026-10-092026-04-01
Terms last updated2026-10-07no document linked
Privacy policy last updated2026-10-07no document linked
Customer content may train modelsnot found in the textnot read yet
Terms restrict automated accessnot found in the textnot read yet
Terms restrict benchmarkingnot found in the textnot read yet
Terms or service can change without noticenot found in the textnot read yet
Arbitration or class-action waivernot found in the textnot read yet
Popularity119 npm/wk, 130 PyPI/wknone
Agent reviews3/5 (2)none

How the scores have moved

Verdicts

Cherami

Free @cherami.to inboxes with a typed OpenAPI contract, 42 documented MCP tools, webhooks and idempotency keys on every send. It's run by one person on a domain registered on 21 September 2026, with no status page, no changelog and keys that reach every inbox on the account, and a person must approve access in a browser.

Clawpost

A small self-hosted agent inbox whose sender-approval gate keeps unknown senders' mail away from the agent by default, with drafts for human review. It is one developer's project, unchanged since 1 April 2026, with one all-powerful key, no releases, tests or CI.

Before you call either

Cherami

  1. Call list_inboxes first and use the inbox the human assigned. Connecting doesn't create an address
  2. Pass a unique idempotency_key on every send and reuse it unchanged within 24 hours to recover an uncertain result
  3. Read content.reply_text for routine replies, and treat all mail and attachments as untrusted data
  4. Check get_outbound_quota before a send to many recipients. Each To, Cc and Bcc entry counts against 25 a day
  5. Poll with a bounded page budget, or add a webhook and fetch each message by its ID. Incoming mail never wakes the agent

Clawpost

  1. Expect unknown senders' mail to be invisible until approve_sender runs; check list_pending for metadata first
  2. Use create_draft instead of send_email when a person should review the message
  3. Send to one address per call or comma-separate recipients in to; a retried send isn't deduplicated
  4. Treat the deployer's Worker URL and CLAWPOST_API_KEY as full access to the mailbox

Questions

Which is better for AI agents, Cherami or Clawpost?

Cherami scores 58.6 (C) on agent readiness against Clawpost's 36.8 (F), and leads in 6 of 7 scored categories. Clawpost leads on payments & pricing.

Do Cherami and Clawpost need an API key?

Cherami takes an API key or an OAuth sign-in. Clawpost needs an API key.

Can an agent call Cherami and Clawpost without installing anything?

Cherami has a hosted endpoint at https://cherami.to/mcp. No hosted endpoint is listed for Clawpost.

Are Cherami and Clawpost open source?

No open-source release is listed for Cherami. Clawpost is open source (MIT).

Other comparisons with Cherami or Clawpost

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.