# Adapters (/docs/v/0.6.0/adapters)



Email SDK ships with 20 adapters. Import only the adapter you use; the package does not ask you
to configure providers that are not on your send path.

Every adapter follows the same contract: map the fields it supports and throw a validation error for
fields the provider API cannot represent. Use the <a href="/docs/v/0.6.0/adapters/field-support">SDK field support guide</a>
before choosing fallback routes.

<SponsorSpotlight />

<ProviderGrid />

## Which adapter should I start with? [#which-adapter-should-i-start-with]

| If you want...                         | Start with                                                                   |
| -------------------------------------- | ---------------------------------------------------------------------------- |
| The fastest first send                 | Resend                                                                       |
| Mature transactional delivery controls | Postmark, SendGrid, AWS SES, Mailgun, Unosend, or Brevo                      |
| A backup route for production delivery | A primary API adapter plus Postmark or SMTP                                  |
| Product-triggered emails               | Iterable, Sequenzy, Loops, or Plunk                                          |
| A cheap or self-managed transport      | SMTP                                                                         |
| Heavy attachment support               | Resend, Postmark, SendGrid, Mailgun, Unosend, MailerSend, Mailtrap, Sequenzy |

## Want to build a community adapter? [#want-to-build-a-community-adapter]

Do not add third-party provider experiments to the official package by default. Publish a separate community package, export an adapter plugin, and list it in the community registry if you want discoverability.

<Cards>
  <Card title="Create an adapter" href="/docs/v/0.6.0/guides/authoring/create-adapter" description="Implement the provider mapping and wrap it as an adapter plugin." />

  <Card title="Publish a community adapter" href="/docs/v/0.6.0/guides/authoring/publish-community-adapter" description="Build and publish a third-party provider package without making it official." />
</Cards>

## What the status labels mean [#what-the-status-labels-mean]

Provider cards use these labels:

* `Official` means the adapter ships in `@opencoredev/email-sdk`.
* `Sponsor` means the provider supports Email SDK. Sponsor adapters appear first in the catalog.
* `API tested` means a local check has successfully called a live provider API with a real key. It does not prove live delivery unless the adapter page says a send was performed.
* `Not API tested` means we have not yet run a live provider API check for that adapter.
* `Request tested` means repository tests cover request mapping, responses, and fail-fast validation with injected fetch calls.
* `Built-in transport` means the adapter sends through Email SDK's own transport implementation instead of a provider API.
* `No provider API` means the adapter does not call a hosted provider API.

Email SDK can catch unsupported fields before a request. It cannot make a provider account ready to send from an unverified domain.

## Import pattern [#import-pattern]

Start with one adapter. Add a fallback only after the fallback supports the same message shape your app sends.

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

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

Route a single send through another configured adapter when a message has a provider-specific job.

```ts
const response = await email.send(
  {
    from: "Acme <hello@acme.com>",
    to: "user@example.com",
    subject: "Password reset",
    text: "Use this link to reset your password.",
  },
  {
    adapter: "smtp",
  },
);

console.log(response.provider);
```

Before adding the provider to production, run a dry run and then a live smoke test from the same environment that will send mail.

```bash
npx email-sdk adapters
RESEND_API_KEY="re_..." npx email-sdk send \
  --dry-run \
  --adapter resend \
  --from "Acme <hello@acme.com>" \
  --to user@example.com \
  --subject "Dry run" \
  --text "Validate only"
```

## Adapter groups [#adapter-groups]

| Group          | Adapters                                                                        |
| -------------- | ------------------------------------------------------------------------------- |
| Popular APIs   | Resend, Postmark, SendGrid, Mailgun, MailerSend, Brevo, Mailchimp Transactional |
| Infrastructure | Cloudflare Email Sending, SparkPost, Mailtrap, Scaleway, ZeptoMail, MailPace    |
| Product-led    | Iterable, Sequenzy, Loops, Plunk                                                |
| Transport      | Built-in SMTP                                                                   |