tinysend is built so an AI agent can sign up, get a token, and start sending — without a human creating an account first. This is the fast path.

1. Register

Ask for an anonymous credential:

POST https://id.tinysend.com/agent/auth
Content-Type: application/json

{ "type": "anonymous" }

You get back a bearer token (sk_...), a claim_token, a user_id, your scopes, and a mailbox you can send from. An anonymous agent starts with a small free tier (10 emails/month).

2. Send an email

One call sends a single message to one recipient — verification links, receipts, notifications, a one-off note:

POST https://api.tinysend.com/v1/emails
Authorization: Bearer sk_...

{
  "from": "you@tinysend.com",
  "to": "team@acme.com",
  "subject": "weekly digest",
  "html": "<p>hello</p>"
}

from is your mailbox address (a name on tinysend.com works with no setup; your own domain works once verified). You get back { "id", "status", "to" }. Send the same Idempotency-Key header twice and the second call returns the original send instead of mailing again.

For recurring sends to a list of subscribers, create a newsletter and send a post to everyone on it:

POST https://api.tinysend.com/v1/lists
{ "name": "Release notes", "type": "newsletter" }

POST https://api.tinysend.com/v1/lists/:id/subscribers
{ "email": "reader@example.com" }

POST https://api.tinysend.com/v1/lists/:id/posts
{ "subject": "Hello", "body_html": "<p>First post</p>" }

POST https://api.tinysend.com/v1/lists/:id/posts/:postId/send

If you hit a 402

You start with 10 emails/month. When you run out, send endpoints return 402 with upgrade options — claim for 100/month, subscribe to a plan over the API, or pay overage inline via MPP. See agent payments.

Receiving email and OTP codes

You got a mailbox at registration, and you can create disposable inboxes with a TTL — useful for signing up for services and reading verification codes programmatically. See agent mailboxes.

Claiming an identity

To raise your limits and unlock write/send, claim a human identity (verify an email with an OTP). When to do it and the merge-vs-link tradeoff: claiming an identity. Protocol details: agent authentication.

Webhooks

Get notified when posts send, subscribers join, or mail arrives instead of polling. See webhooks.

Going further

The whole API is documented at /developers/api and the spec is at api.tinysend.com/v1/openapi.json. For everything tinysend exposes to agents, see the agents page.

Questions?

Contact us at hi@tinysend.com.

Agent quickstart — tinysend agents