Email for agents.

Sign up with one API call. No OAuth, no credit card, no human required. Get your own email address, start sending and receiving immediately.

Quick start

curl -X POST https://inboxkit.cc/api/signup \
  -H "Content-Type: application/json" \
  -d '{"handle": "your-name"}'

# {
#   "email": "your-name@inboxkit.cc",
#   "apiKey": "ik_..."
# }

That's it. Use the API key as a Bearer token for all other endpoints.

How it works

→ Sign up, get email. One POST, no approval. You get a real email address and an API key back.
→ Send email. Send to anyone: humans, services, other agents. Standard email, delivered normally.
→ Receive email. Poll your inbox or set up a webhook. Messages from anyone on the internet land in your inbox.
→ Webhooks. Register a URL and get notified on inbound mail. HMAC-signed payloads, delivery IDs for idempotency.

API reference

Base URL: https://inboxkit.cc

Method	Path	Auth	Description
`POST`	`/api/signup`	None	Create an inbox. Returns email + API key.
`POST`	`/api/messages`	Bearer	Send an email.
`GET`	`/api/messages`	Bearer	List messages. Use `?unread=true` for new messages only.
`GET`	`/api/messages/:id`	Bearer	Read a specific message.
`PATCH`	`/api/messages/:id`	Bearer	Mark a message as read or unread.
`PUT`	`/api/webhook`	Bearer	Set webhook URL for inbound mail notifications.
`GET`	`/api/webhook`	Bearer	Get current webhook configuration.
`DELETE`	`/api/webhook`	Bearer	Remove webhook.

Full spec: OpenAPI 3.1 · llms.txt

Give this to your agent

Copy this prompt and paste it into your agent to set up email.

Sign up for an InboxKit email address.

API base: https://inboxkit.cc

1. POST /api/signup with {"handle": "your-chosen-name"} to create an inbox.
   You'll get back an email address and an API key.
2. Use the API key as a Bearer token for all other requests.
3. POST /api/messages to send email.
4. GET /api/messages?unread=true to list new messages.
5. GET /api/messages/:id to read a message.
6. PATCH /api/messages/:id with {"read": true} to mark it as processed.
7. Optionally, PUT /api/webhook with {"url": "https://..."} to get
   notified on inbound mail instead of polling.

Full API spec: https://inboxkit.cc/api/openapi.json