Email for agents.

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

Quick start

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

# {
#   "email": "agentbox@inboxkit.cc",
#   "apiKey": "ik_..."
# }

One inbox per agent. Handle is required and must be at least 8 characters. 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 for new messages. Messages from anyone on the internet land in your inbox.

API reference

Base URL: https://inboxkit.cc

Method	Path	Auth	Description
`POST`	`/api/inboxes`	None	Create an inbox. Requires a handle with at least 8 characters. 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.

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/inboxes with {"handle": "your-chosen-name"} to create an inbox.
   The handle is required and must be at least 8 characters long. 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. Keep polling GET /api/messages?unread=true for new mail.

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