# Quickstart (/docs/v/0.2.1/getting-started/quickstart)



Install the SDK:

```bash
bun add @opencoredev/email-sdk
```

This example sends through Resend. Set `RESEND_API_KEY` in the environment before running it.

```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! })],
});

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

## Add built-in SMTP fallback [#add-built-in-smtp-fallback]

Add SMTP when you want a second route for the same transactional email. The SMTP adapter is built in
and does not require Nodemailer. When SMTP auth is configured on a non-secure connection, Email SDK
upgrades with STARTTLS before authenticating.

Only use fallback adapters that can send the same message shape. For example, SMTP supports address
fields and headers, but not provider-only fields like tags, metadata, or attachments.

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

export const email = createEmailClient({
  adapters: [
    resend({ apiKey: process.env.RESEND_API_KEY! }),
    smtp({
      host: "smtp.purelymail.com",
      port: 587,
      auth: {
        user: process.env.SMTP_USER!,
        pass: process.env.SMTP_PASS!,
      },
    }),
  ],
  fallback: ["smtp"],
});
```

Your application still sends the same way:

```ts
await email.send({
  from: "Acme <hello@acme.com>",
  to: "user@example.com",
  subject: "Receipt",
  text: "Thanks for your order.",
});
```

## Check the result [#check-the-result]

`send` resolves with the normalized adapter response. The `provider` value tells you which adapter
actually handled the send.

```ts
const result = await email.send(message);

console.log(result.provider);
console.log(result.id);
```

If the adapter returns a message ID, Email SDK exposes it as both `id` and `messageId`. Provider
responses are still available through `raw` when an adapter includes them.

## Test from the CLI [#test-from-the-cli]

Use the CLI to check adapter credentials from your terminal.

```bash
email-sdk doctor --adapter resend
```

Send a test email:

```bash
email-sdk send \
  --adapter resend \
  --from "Acme <hello@acme.com>" \
  --to "user@example.com" \
  --subject "Hello" \
  --text "It works"
```

Use `--dry-run` when you want to validate the message and selected adapter without sending email.