# DevInbox

> Programmatic email inboxes for AI agents and test suites. Create an inbox in
> milliseconds, wait for the verification email, extract the code as structured
> data — then send or reply from that same address. REST API or MCP. Custom
> domains included.

DevInbox gives an AI agent (or an automated test suite) a real, persistent email
address it can act on: sign up for a service, receive a verification email, and
read the one-time code back as structured JSON — then send email or reply from
that same address. Everything is available as a plain REST API and as a hosted
MCP server (mcp.devinbox.io), so any MCP client — Claude, LangGraph, CrewAI, or
your own — can create inboxes, wait for mail, and send with no glue code.

## Core capabilities

- Create isolated inboxes in milliseconds (devinbox.io addresses or your own custom domain)
- `wait_for_email` blocks until a message arrives, then returns it
- Template extraction returns structured data (e.g. `{ "code": "482913" }`) instead of raw HTML
- Agents can define and validate their own extraction templates at runtime
- Every persistent inbox can also send, not just receive — `POST https://api.devinbox.io/messages/{inbox_key}/send` (REST, X-Api-Key auth with the `send` scope) or the `send_email` MCP tool, closing the agent loop: `wait_for_email` → act → `send_email`
- Reply into an existing thread by passing `inReplyTo` (the id of a message received in that inbox); DevInbox sets real In-Reply-To/References headers so the reply lands in the recipient's thread. Mail is sent from the inbox's own `{key}@devinbox.io` address, SPF/DKIM-authenticated
- Free tier is reply-only by design — every send must reference a received message, a deliberate anti-spam and deliverability choice (100 sends/month); paid plans from $15/mo add cold outbound and higher volume
- Inbound routing, forwarders, and webhooks work identically on custom domains
- Usage is metered in "operations"; a generous free tier requires no credit card

## Docs

- Documentation: https://devinbox.io/doc
- Getting started: https://devinbox.io/doc/getting-started
- Agents & MCP guide: https://devinbox.io/doc/ai-agents
- API guide: https://devinbox.io/doc/api-guide
- Developer guide: https://devinbox.io/doc/developer-guide
- QA engineer guide: https://devinbox.io/doc/qa-engineer-guide
- Integration tests: https://devinbox.io/doc/integration-tests
- Email templates: https://devinbox.io/doc/templates

## Product

- Pricing: https://devinbox.io/#pricing
- Sign in: https://app.devinbox.io/Account/Login
- Get started: https://app.devinbox.io/Account/Register