Introduction

send0 is the API-first email platform for developers. One typed API to send transactional and marketing email, and receive it too — inbound parsing, programmable inboxes, and a retrieve API, with deliverability built in.

One API for email. Send and receive.

Why send0?

Most teams bolt one provider for sending email onto something else entirely for receiving it. send0 does both behind a single integration — a Resend-grade sending API plus inboxes you can program.

• Send — Transactional and marketing email via POST /v1/emails, with idempotency, batch sends, and JSX templates.
• Receive — Inbound routing, MIME parsing, an email.received webhook, a retrieve API, IMAP/POP, threading, and search.
• Deliverability — Shared and dedicated IPs, automated warmup, SPF/DKIM/DMARC, and suppression enforced on every send.
• TypeScript SDK — First-class SDK with full type safety and auto-completion.
• Webhooks — Real-time, HMAC-signed delivery and inbound events pushed to your server.
• Test mode — Sandbox environment with sk_test_ keys. No real sends. Ever.

Current status

Base URL

All API requests are made to:

https://api.send0.dev/v1

Send your first email

Install the SDK and send an email in four lines of code.

import { Send0 } from 'send0';

const send0 = new Send0('sk_live_...');

await send0.emails.send({
  from: 'hello@yourdomain.com',
  to: 'user@example.com',
  subject: 'Welcome!',
  html: '<p>Hello from send0</p>',
});

That's it. No configuration files, no complex setup, no provider-specific logic.

Next steps

• Quickstart — Send your first email in under 5 minutes.
• Authentication — Learn about API key types and security.
• Error Handling — Understand error responses and handle them gracefully.

Key resources