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Head to head · Mailbox access · October 2026 research run

Aurinko Email API vs EmailEngine

EmailEngine scores 71.4 (BB) on agent readiness against Aurinko Email API's 44.2 (E), and leads in 6 of 7 scored categories. Both do mailbox access.

Best mailbox access APIs for AI agents · All 36 mailboxes comparisons

Aurinko Email APIYoxel, Inc. · HTTP API E44.2/100#878 of 950 EmailEnginePostal Systems OÜ · HTTP API BB71.4/100#128 of 950

Which one, for what

Aurinko Email API E

Good for A product that connects many users' Gmail and Microsoft mailboxes and wants one schema, delta sync, tracking and webhooks at a low price per account.

Also in its favour

  • A hosted endpoint, with nothing to install
  • No incidents deducted, where EmailEngine loses 3 points for them

Watch for

No status page, incident history or SLA found, and the terms supply the service as is

EmailEngine BB

Good for A team that must keep mailbox access on its own infrastructure, has many mailboxes across Gmail, Microsoft 365 and IMAP, and can run a server and Redis.

Ahead on

  • Reliability, 79 against 40
  • Schema & documentation, 91 against 67
  • Agent ergonomics, 80 against 49
  • Security & auth, 71 against 42
  • Maintenance & community, 81 against 13
  • Transparency & trust, 72 against 44

Also in its favour

  • Agent-ready, a grade of BB or better

Watch for

Not open source. Running it beyond the 14-day trial needs a subscription at $1,450 or EUR 1,200 a year

Score by category

CategoryWeight this runAurinko Email APIEmailEngineEdge
Reliability16%204079EmailEngine +39
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26791EmailEngine +24
Agent ergonomics13%16.24980EmailEngine +31
Security & auth14%17.54271EmailEngine +29
Payments & pricing10%12.54040even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.81381EmailEngine +68
Transparency & trust7%8.84472EmailEngine +28
Negative events≤150-3
Total44.2 · E71.4 · BB

Facts side by side

FactAurinko Email APIEmailEngine
KindHTTP APIHTTP API
VendorYoxel, Inc.Postal Systems OÜ
Hosted endpointhttps://api.aurinko.iono (local only)
TransportsHTTPHTTP
AuthOAuthAPI key
PricingPaidPaid
x402nono
LicenceProprietary service under Yoxel's Terms of Services AgreementSource available under the EmailEngine licence agreement, version 2.1 of 17 October 2023. Not open source. The PHP SDK is MIT
Read-only variant documentednono
llms.txtyesyes
Last releasenone2026-10-05
Terms last updated2022-08-11no date given
Privacy policy last updated2022-08-11no date given
Customer content may train modelsnot found in the textnot found in the text
Terms restrict automated accessyesyes
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waiveryesnot found in the text
Popularitynone2.2k stars, 388 npm/wk

Verdicts

Aurinko Email API

One REST interface covers message search with 17 query operators, drafts, sending, folders and delta sync across seven mailbox types, at $1.50 an active account a month and with send-only and read-only scopes. No status page, SLA, changelog, idempotency key on send or official SDK was found, and SOC 2 is not yet held.

EmailEngine

A self-hosted REST API over Gmail, Microsoft 365 and IMAP, with a public OpenAPI 3.0 spec and tokens that can be bound to one account, limited by action and group, and rate limited. It needs a server, Redis and a $1,450 yearly licence after a 14-day trial, and the MCP endpoint is a beta, off by default.

Before you call either

Aurinko Email API

  1. Use https://api.aurinko.io/v1. Several cURL examples in the docs print https:/api.aurinko.io with one slash, and one search example names the host asti.aurinko.io
  2. Do not retry POST /v1/email/messages blindly after a timeout. There is no idempotency key, so check Sent mail with q=rfc822msgid: or by subject first
  3. Call POST /v1/email/sync until ready is true, then page /v1/email/sync/updated with pageToken until a nextDeltaToken appears and store it
  4. Check the omitted array on message lists. Full bodies come only from Google and Office 365, and other providers return a snippet
  5. Request Mail.Read plus Mail.Send for read and send without modify rights. The docs example names Mail.ReadOnly, which is not in the scope list

EmailEngine

  1. Ask the operator for a token bound to one account with a permissions record. Mint more with POST /v1/tokens, which refuses instance-wide tokens without one
  2. Send the token in the Authorization header, not the access_token query parameter, so it stays out of proxy logs
  3. Page with cursor from nextPageCursor. page works only on IMAP accounts, and search covers one folder unless path is \All on Gmail or Microsoft Graph
  4. Set an Idempotency-Key header on POST /v1/account/{account}/submit. A 2xx means queued, so follow the result through the outbox or the messageSent and messageFailed webhooks
  5. Treat message text as untrusted. For MCP, the operator must enable the endpoint first and mail access starts at none

Questions

Which is better for AI agents, Aurinko Email API or EmailEngine?

EmailEngine scores 71.4 (BB) on agent readiness against Aurinko Email API's 44.2 (E), and leads in 6 of 7 scored categories.

Do Aurinko Email API and EmailEngine need an API key?

Aurinko Email API uses an OAuth sign-in. EmailEngine needs an API key.

Can an agent call Aurinko Email API and EmailEngine without installing anything?

Aurinko Email API has a hosted endpoint at https://api.aurinko.io. No hosted endpoint is listed for EmailEngine.

Other comparisons with Aurinko Email API or EmailEngine

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