<!-- https://headless-lms.dev/docs/adapters -->

# Adapters

Adapters are what makes headless-lms incredibly extendable.

Adapters are implementations of the outbound ports declared in `@headless-lms/core`. These are the
capabilities like email delivery, email templates, object storage, durable workflows etc.

For example, system emails are sent using Resend. If you want to use a different email provider, then implement your
own Email adapter and pass it in to the server.

A running server wires these adapters together at startup:

```ts title="main.ts"
import { createContainer, buildServer } from "@headless-lms/server";
import { ResendEmailAdapter } from "@headless-lms/adapter-email-resend";
import { MinioStorageAdapter } from "@headless-lms/adapter-storage-minio";
import { ReactEmailTemplateRenderer } from "@headless-lms/adapter-email-templates";
import { HatchetAutomationEngine } from "@headless-lms/adapter-workflow-hatchet";

const container = await createContainer(config, {
  adapters: {
    email: new ResendEmailAdapter({ apiKey, from }),
    storage: new MinioStorageAdapter(storageConfig),
    templates: new ReactEmailTemplateRenderer(),
    workflows: new HatchetAutomationEngine(),
  },
});
```

Every slot is optional, with a sensible default, so you can start with nothing configured and add adapters as you need them.

## Available adapters

| Slot | Port | Default adapter | Absent → |
| --- | --- | --- | --- |
| `email` | `EmailSender` | [`@headless-lms/adapter-email-resend`](/docs/adapters/email/resend) | Stub that fails loudly on send |
| `templates` | `TemplateRenderer` | [`@headless-lms/adapter-email-templates`](/docs/adapters/email/react-email) | Stub that fails loudly on render |
| `storage` | `ObjectStorage` | [`@headless-lms/adapter-storage-minio`](/docs/adapters/storage/minio) | Stub that fails loudly on use |
| `workflows` | `AutomationEngine` | [`@headless-lms/adapter-workflow-hatchet`](/docs/adapters/workflows/hatchet) | In-process engine, one attempt per action |

Because each slot is just an interface, you can replace any adapter with your own implementation — implement the port from `@headless-lms/core/types` and pass it in the same way.

An installation scaffolded with `npm create headless-lms` comes with one adapter wired: MinIO storage, and only when `STORAGE_ENDPOINT` is set. Every other slot sits on its default, so a fresh project boots against nothing but Postgres. Add the adapters above as you need them — `apps/api` in the repository is the fully wired reference (Resend, MinIO, React Email, Hatchet).