---
name: better-auth-integration
description: Dodo Payments plugin for Better Auth (@dodopayments/better-auth) covering customer sync on signup, authenticated checkout, customer portal, usage ingestion, and verified webhooks. Use when an app uses Better Auth and needs the dodopayments, dodopaymentsClient, checkout, portal, usage, or webhooks plugins; for other auth stacks use framework-adapters.
---

# Better Auth Integration

Use `@dodopayments/better-auth` to synchronize Better Auth users with Dodo Payments and expose authenticated checkout, customer portal, subscription, payment, usage, and webhook endpoints.

## When to use this skill

- Create a Dodo customer automatically when a Better Auth user signs up.
- Start checkout for a signed-in user without exposing a Dodo API key.
- Let users open their customer portal or list their subscriptions and payments.
- Submit metered usage for the signed-in customer.
- Receive signature-verified Dodo webhooks through Better Auth.

## Install

```bash
npm install @dodopayments/better-auth dodopayments better-auth zod
```

Requires Better Auth 1.4 or a later 1.x release.

The package exports the lowercase server functions `dodopayments`, `checkout`, `portal`, `usage`, and `webhooks`. Its client entry point exports `dodopaymentsClient`.

## Server setup

Every endpoint is registered by a feature in `use`. Include every feature that the application calls; omitting one makes its route return 404.

```typescript
import { betterAuth } from "better-auth";
import DodoPayments from "dodopayments";
import { checkout, dodopayments, portal, usage, webhooks } from "@dodopayments/better-auth";

const dodoPayments = new DodoPayments({
  bearerToken: process.env.DODO_PAYMENTS_API_KEY,
  environment: "test_mode",
});

export const auth = betterAuth({
  database: {
    // your database config
  },
  plugins: [
    dodopayments({
      client: dodoPayments,
      createCustomerOnSignUp: true,
      // `user` here is Better Auth's base user: id, name, email, emailVerified,
      // image, createdAt, updatedAt. Anything else (phone number, company, plan)
      // must first be declared via `user.additionalFields` in your Better Auth
      // config, otherwise it does not exist on the type and will be undefined.
      getCustomerParams: (user) => ({
        metadata: { better_auth_user_id: user.id },
      }),
      use: [
        checkout({
          products: [
            { productId: "pdt_premium", slug: "premium-plan" },
          ],
          successUrl: "https://app.example.com/billing/success",
          authenticatedUsersOnly: true,
        }),
        portal(),
        usage(),
        webhooks({
          webhookKey: process.env.DODO_PAYMENTS_WEBHOOK_KEY,
          onPayload: async (payload) => {
            console.log("Verified Dodo webhook:", payload.type);
          },
        }),
      ],
    }),
  ],
});
```

`products` maps an application slug to a Dodo product ID. `authenticatedUsersOnly: true` requires a Better Auth session for checkout. `getCustomerParams` adds application metadata when customer synchronization runs.

The plugin adds a `dodoCustomerId` field to the Better Auth `user` table. After adding the plugin, update your database schema with the [Better Auth CLI](https://www.better-auth.com/docs/concepts/cli):

```bash
npx auth generate   # generate the ORM schema or SQL migration, then apply it yourself
npx auth migrate    # or apply it directly (built-in Kysely adapter only)
```

## Browser client setup

```typescript
import { createAuthClient } from "better-auth/react";
import { dodopaymentsClient } from "@dodopayments/better-auth/client";

export const authClient = createAuthClient({
  plugins: [dodopaymentsClient()],
});
```

These are browser methods. They send the Better Auth session cookie automatically; do not pass `request.headers` to them.

## Create a checkout session

```typescript
import { authClient } from "@/lib/auth-client";

async function startCheckout() {
  const { data: session, error } = await authClient.dodopayments.checkoutSession({
    slug: "premium-plan",
    referenceId: "order_123",
  });

  if (error) {
    console.error("Checkout error:", error);
    return;
  }

  if (session) {
    window.location.href = session.url;
  }
}
```

`slug` must match a product configured in `checkout({ products: [...] })`. `referenceId` is optional reconciliation metadata.

## Open the customer portal

```typescript
const { data: portalSession, error } =
  await authClient.dodopayments.customer.portal();

if (error) {
  console.error("Portal error:", error);
} else if (portalSession?.redirect) {
  window.location.href = portalSession.url;
}
```

The portal endpoint requires a signed-in, verified user and resolves that user's synchronized Dodo customer.

## List subscriptions and payments

```typescript
const { data: subscriptions, error: subscriptionsError } =
  await authClient.dodopayments.customer.subscriptions.list({
    query: { page: 1, limit: 10, status: "active" },
  });

const { data: payments, error: paymentsError } =
  await authClient.dodopayments.customer.payments.list({
    query: { page: 1, limit: 10, status: "succeeded" },
  });

if (subscriptionsError || paymentsError) {
  console.error("Could not load billing history");
} else {
  console.log("Subscriptions:", subscriptions?.items);
  console.log("Payments:", payments?.items);
}
```

Both list responses use an `items` envelope. Subscription filters accept `page`, `limit`, and `status`; payment filters use the same pagination fields and payment statuses.

## Ingest metered usage

Enable `usage()` on the server, then submit an event for the signed-in customer:

```typescript
const { data, error } = await authClient.dodopayments.usage.ingest({
  event_id: "evt_usage_123",
  event_name: "api_calls",
  metadata: { requests: 100 },
  timestamp: new Date(),
});

if (error) {
  console.error("Usage ingestion failed:", error);
} else {
  console.log("Ingested events:", data?.ingested_count);
}
```

Both `usage.ingest` and `usage.meters.list` require a signed-in user with a verified email address. The plugin derives `customer_id` from the authenticated session. `event_id` is the event's idempotency key; reuse it when retrying the same event.

## Webhook endpoint

`webhooks({ webhookKey, onPayload })` verifies and handles the request itself. With Better Auth's default `/api/auth` base path, configure this URL in the Dodo dashboard:

```text
https://app.example.com/api/auth/dodopayments/webhooks
```

Do not create a second route and do not call `auth.api.dodopayments.verifyWebhook()`; that method does not exist. The plugin reads the raw request, verifies the Standard Webhooks signature with `webhookKey`, and invokes `onPayload` plus any configured event-specific callback.

## Registered endpoints

- `POST /dodopayments/checkout`
- `POST /dodopayments/checkout-session`
- `GET /dodopayments/customer/portal`
- `GET /dodopayments/customer/subscriptions/list`
- `GET /dodopayments/customer/payments/list`
- `POST /dodopayments/usage/ingest`
- `GET /dodopayments/usage/meters/list`
- `POST /dodopayments/webhooks`

Better Auth prefixes these plugin paths with its configured API base path.

## Common mistakes

**Enabling only `portal()`.** Checkout, usage, and webhook routes do not exist unless `checkout()`, `usage()`, and `webhooks()` are also present in `use`.

**Mixing browser and server APIs.** Call `authClient.dodopayments...` in browser code without a `headers` option. Use Better Auth's server API separately when handling server requests.

**Creating duplicate customers.** When `createCustomerOnSignUp` is enabled, do not also call `client.customers.create()` for the same user.

**Granting access from browser state.** Treat verified webhook events or a server-side Dodo lookup as the source of truth for entitlements.

**Adding a custom webhook verifier.** The plugin owns `/dodopayments/webhooks`, signature verification, and callback dispatch.

## Resources

- [Better Auth Adapter](https://docs.dodopayments.com/developer-resources/better-auth-adaptor)
- [Dodo Payments Better Auth package](https://www.npmjs.com/package/@dodopayments/better-auth)
- [Dodo Payments SDK](https://github.com/dodopayments/dodopayments-typescript)