payload-v3-endpoints - SKILL.md Agent Skill

name: payload-v3-endpoints description: Provides correct Payload CMS v3 endpoint patterns and logger API usage. Use when writing or fixing REST API endpoints, custom handlers, or when encountering TypeScript errors with req.data, req.cookies, or logger calls.

Ensure all Payload v3 endpoints and logger calls follow the correct patterns to avoid runtime errors and TypeScript issues. **WRONG (Payload v2 pattern):** ```typescript handler: async (req, res) => { const data = req.data // undefined in v3! res.status(200).json({ success: true }) } ```

CORRECT (Payload v3 pattern):

handler: async (req) => {
  const data = await req.json()
  return Response.json({ success: true }, { status: 200 })
}

Alternative using helper:

import { addDataAndFileToRequest } from 'payload'

handler: async (req) => {
  await addDataAndFileToRequest(req)
  const data = req.data  // now available
  return Response.json({ success: true })
}

**WRONG:** ```typescript res.status(200).json({ message: 'success' }) res.json({ message: 'success' }) ```

CORRECT:

return Response.json({ message: 'success' }, { status: 200 })
return Response.json({ message: 'success' })  // defaults to 200

Error responses:

return Response.json({ error: 'Not found' }, { status: 404 })
return Response.json({ error: 'Unauthorized' }, { status: 401 })

**WRONG:** ```typescript const token = req.cookies.token // undefined in v3! ```

CORRECT:

const cookieHeader = req.headers.get('cookie')
const cookies = parseCookies(cookieHeader)
const token = cookies.token

**WRONG:** ```typescript handler: async (req, res) => { ... } ```

CORRECT:

handler: async (req) => { ... }
// or with PayloadRequest type
handler: async (req: PayloadRequest) => { ... }

Payload uses pino logger. The signature is: `logger.info(object, message)` NOT `logger.info(message, object)`

WRONG:

req.payload.logger.info('User created', { userId: 123 })
req.payload.logger.error('Failed to save:', error)

CORRECT:

req.payload.logger.info({ userId: 123 }, 'User created')
req.payload.logger.error({ error: String(error) }, 'Failed to save')

For simple messages (no object):

req.payload.logger.info('Operation completed')  // This is fine

Complete endpoint example: ```typescript import type { Endpoint, PayloadRequest } from 'payload'

export const myEndpoint: Endpoint = { path: '/my-endpoint', method: 'post', handler: async (req: PayloadRequest) => { try { const data = await req.json()

  // Access payload
  const result = await req.payload.find({
    collection: 'users',
    where: { email: { equals: data.email } }
  })

  req.payload.logger.info({ count: result.totalDocs }, 'Found users')

  return Response.json({
    success: true,
    data: result
  })
} catch (error) {
  req.payload.logger.error({ error: String(error) }, 'Endpoint failed')
  return Response.json({ error: 'Internal error' }, { status: 500 })
}

} }

</pattern>

</critical_patterns>

<common_errors>
| Error | Cause | Fix |
|-------|-------|-----|
| `req.data is undefined` | Using v2 pattern | Use `await req.json()` |
| `req.cookies is undefined` | Using v2 pattern | Parse from `req.headers.get('cookie')` |
| `res.json is not a function` | Handler has wrong signature | Return `Response.json()` |
| `TS2769: No overload matches` on logger | Wrong argument order | Put object first, message second |
| `Type 'string \| string[]' not assignable` | relationTo can be array | Use `Array.isArray(x) ? x[0] : x` |
</common_errors>

<quick_reference>
```typescript
// Request body
const data = await req.json()

// Response
return Response.json({ data }, { status: 200 })

// Logger
req.payload.logger.info({ key: value }, 'Message')
req.payload.logger.error({ error: String(e) }, 'Error message')

// Handler signature
handler: async (req: PayloadRequest) => { ... }

- All endpoints use `await req.json()` for body access - All responses use `Response.json()` - All logger calls have object first, message second - Handler signature is `(req)` not `(req, res)` - TypeScript compiles without errors