MongoDB

Run payload-better-auth on Payload's MongoDB adapter. The adapter detects MongoDB itself; three settings change from the Postgres setup.

The adapter detects MongoDB from Payload's database adapter and configures itself, so payloadAdapter() needs no extra options. IDs are always text (ObjectId strings) on MongoDB.

Differences from Postgres

	Postgres (default)	MongoDB
ID type	`'number'` (SERIAL)	`'text'` (ObjectId strings)
`advanced.database.generateId`	Set to `'serial'`	Do not set
`betterAuthStrategy()`	Default	`idType: 'text'`

Payload config

Install the MongoDB adapter instead of the Postgres adapter:

npm i @payloadcms/db-mongodb

Keep the secrets and app origin from Installation, and replace DATABASE_URL with:

.env

DATABASE_URI=mongodb://127.0.0.1:27017/my-app

src/payload.config.ts

import { buildConfig } from 'payload'
import { mongooseAdapter } from '@payloadcms/db-mongodb'
import { betterAuth } from 'better-auth'
import {
  betterAuthCollections,
  createBetterAuthPlugin,
  payloadAdapter,
} from '@delmaredigital/payload-better-auth'
import { betterAuthOptions } from './lib/auth/config'
import { Users } from './collections/Users'
import { getBaseUrl } from './lib/auth/getBaseUrl'

const baseUrl = getBaseUrl()

export default buildConfig({
  secret: process.env.PAYLOAD_SECRET!,
  collections: [Users],
  plugins: [
    betterAuthCollections({ betterAuthOptions, skipCollections: ['user'] }),
    createBetterAuthPlugin({
      createAuth: (payload) =>
        betterAuth({
          ...betterAuthOptions,
          database: payloadAdapter({ payloadClient: payload }),
          // Do NOT set advanced.database.generateId
          secret: process.env.BETTER_AUTH_SECRET,
          baseURL: baseUrl,
          trustedOrigins: [baseUrl],
        }),
    }),
  ],
  db: mongooseAdapter({ url: process.env.DATABASE_URI! }),
})

Users collection and session helpers

src/collections/Users/index.ts

import type { CollectionConfig } from 'payload'
import { betterAuthStrategy } from '@delmaredigital/payload-better-auth'

export const Users: CollectionConfig = {
  slug: 'users',
  auth: {
    disableLocalStrategy: true,
    strategies: [betterAuthStrategy({ idType: 'text' })],
  },
  access: {
    read: ({ req }) => {
      if (!req.user) return false
      if (req.user.role === 'admin') return true
      return { id: { equals: req.user.id } }
    },
    admin: ({ req }) => req.user?.role === 'admin',
  },
  fields: [
    { name: 'email', type: 'email', required: true, unique: true },
    { name: 'emailVerified', type: 'checkbox', defaultValue: false },
    { name: 'name', type: 'text' },
    { name: 'image', type: 'text' },
    {
      name: 'role',
      type: 'select',
      defaultValue: 'user',
      options: [
        { label: 'User', value: 'user' },
        { label: 'Admin', value: 'admin' },
      ],
    },
  ],
}

src/lib/auth.ts

import { createSessionHelpers } from '@delmaredigital/payload-better-auth'
import type { User } from '@/payload-types'

export const { getServerSession, getServerUser } = createSessionHelpers<User>({
  idType: 'text',
})

Migrating from Postgres to MongoDB

Remove generateId: 'serial' from your Better Auth config.

Change betterAuthStrategy() to betterAuthStrategy({ idType: 'text' }).

Set idType: 'text' on createSessionHelpers.

Remove any explicit idType: 'number' from payloadAdapter's adapterConfig.

Switch Payload's database adapter to mongooseAdapter.

The atomic SQL path described in Atomic operations is Postgres-only. On MongoDB, consumeOne and incrementOne use the Local API.

Differences from PostgresCopy Anchor Link

Payload configCopy Anchor Link

Users collection and session helpersCopy Anchor Link

Migrating from Postgres to MongoDBCopy Anchor Link

On this page

Differences from Postgres

Payload config

Users collection and session helpers

Migrating from Postgres to MongoDB