TRANSACTIONAL EMAIL API

The open-source transactional email API for applications.

Send receipts, verification messages, product notifications, and alerts from the software you already run. No AI agent or agent framework is required.

Start with outbound email over HTTP, TypeScript, or Python. Add replies, threading, approval, or an agent-owned inbox only when your product needs them.

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Start simple. Keep the richer email workflow available.

Application email

Send receipts, verification messages, alerts, and product notifications from your backend.

Typed integrations

Use the TypeScript or Python SDK, or call the documented HTTP API from any language.

Two-way when needed

Add inbound email, persistent threads, signed webhooks, and WebSocket delivery without changing providers.

Human approval

Optionally hold sensitive outbound messages for a person to approve, edit, or reject.

ONE RESOURCE MODEL

A sender now. An inbox when you need one.

In the e2a API, each sending identity is represented by an agent resource. For a conventional application, treat it as the sender and optional inbox; the name describes the resource, not a requirement to run AI. That same identity can later receive replies or participate in an automated workflow without a second email system.

await client.messages.send("[email protected]", {
  to: [{ email: "[email protected]" }],
  subject: "Your receipt",
  text: "Thanks for your order.",
});

Transactional email API: FAQ

Can e2a be used as a general transactional email API?

Yes. Any application can use e2a's HTTP API and TypeScript or Python SDKs to send transactional email. Agent inboxes, inbound email, threading, and human approval are additional capabilities—not requirements.

Do I need an AI agent or agent framework to use e2a?

No. A conventional backend, scheduled job, serverless function, command-line script, or internal service can call e2a directly. An AI runtime is optional and is only needed when your product actually contains an agent.

Can I self-host the transactional email API?

Yes. e2a is Apache-2.0 open source, including the Go server, SMTP relay, TypeScript and Python SDKs, CLI, MCP server, and dashboard. You can run it with your own Postgres database and outbound SMTP relay, or use the hosted service.

Send your first application email.

Start free with the hosted service, or run the Apache-2.0 stack yourself.

Create a sender →