# Email SDK

> An open-source TypeScript SDK for transactional email. 27 adapters. One typed SDK.

Email SDK is an open-source TypeScript SDK (npm: `@opencoredev/email-sdk`) for sending transactional email through 26 provider APIs plus SMTP — Resend, SMTP, Postmark, SendGrid, Mailgun, Cloudflare Email Sending, Unosend, AWS SES, and more — behind one typed `send()` call with retries and compatible fallbacks. It is a library you install into a TypeScript/JavaScript app, **not** a hosted API or a service you sign up for. There are no credentials to obtain from us; you bring the provider keys your app already has.

## Install

```bash
npm install @opencoredev/email-sdk
```

## Send an email

```ts
import { createEmailClient } from "@opencoredev/email-sdk";
import { resend } from "@opencoredev/email-sdk/resend";

const email = createEmailClient({
  adapters: [resend({ apiKey: process.env.RESEND_API_KEY! })],
  retry: { maxAttempts: 2 },
});

await email.send({
  from: "Acme <hello@acme.com>",
  to: "user@example.com",
  subject: "Welcome",
  text: "Your account is ready.",
});
```

## Why use it

- **Switch providers without rewriting your app.** Adapters import from their own entry points (`@opencoredev/email-sdk/resend`, `/smtp`, `/ses`, …) while every send site keeps the same typed call.
- **Retries and fallbacks.** Retry transient failures and route across compatible adapters automatically.
- **Agent-ready.** `createEmailAgentTools(client)` from `@opencoredev/email-sdk/agent-tools` returns a guarded `send_email` tool that runs the full validate/retry/fallback pipeline.
- **Local CLI.** `email-sdk doctor` and `send --dry-run` check configuration and test sends before going live.

## For agents

- Agent guide: https://email-sdk.dev/agents.md
- Authentication model: https://email-sdk.dev/auth.md
- Machine index: https://email-sdk.dev/llms.txt and https://email-sdk.dev/llms-full.txt
- Discovery file: https://email-sdk.dev/.well-known/agent.json

## Links

- Documentation: https://email-sdk.dev/docs
- Source: https://github.com/opencoredev/email-sdk
- Package: https://www.npmjs.com/package/@opencoredev/email-sdk