Prisma

Connect Better Auth to your database using Prisma ORM.

Prisma is a type-safe database toolkit for TypeScript. Better Auth ships a first-class Prisma adapter that supports SQLite, PostgreSQL, MySQL, CockroachDB, SQL Server, and MongoDB via Prisma.

Installation

1. Install Prisma and the Prisma Client

   npm

   npm install @prisma/client
   npm install --save-dev prisma
   

   pnpm

   pnpm add @prisma/client
   pnpm add -D prisma
   

   yarn

   yarn add @prisma/client
   yarn add --dev prisma
   

   bun

   bun add @prisma/client
   bun add -d prisma
   
2. Configure the adapter

   Import prismaAdapter from better-auth/adapters/prisma and pass a PrismaClient instance:

   auth.ts

   import { betterAuth } from "better-auth";
   import { prismaAdapter } from "better-auth/adapters/prisma";
   import { PrismaClient } from "@prisma/client";
   
   const prisma = new PrismaClient();
   
   export const auth = betterAuth({
     database: prismaAdapter(prisma, {
       provider: "postgresql", // "sqlite" | "postgresql" | "mysql" | "cockroachdb" | "sqlserver" | "mongodb"
     }),
   });
   

Starting from Prisma 7, the output path field is required in schema.prisma. If you configured a custom output path (e.g. output = "../src/generated/prisma"), import PrismaClient from that location instead of @prisma/client.

Configuration options

The prismaAdapter function accepts a PrismaClient instance and a config object:

Option	Type	Description
provider	"sqlite" | "postgresql" | "mysql" | "cockroachdb" | "sqlserver" | "mongodb"	The database provider. Required.
usePlural	boolean	Set to true when your Prisma models use plural names. Defaults to false.
debugLogs	boolean	Enable verbose adapter logging. Defaults to false.
transaction	boolean	Wrap multi-step operations in a Prisma transaction. Defaults to false.

Prisma schema

The Better Auth CLI generates the required Prisma schema models based on your configuration and plugins.

npx auth@latest generate

Schema generation is supported. Schema migration must be run separately through Prisma:

npx prisma migrate dev

Core schema

The schema below is the baseline required by Better Auth. The CLI generates this for you, including @relation directives needed for experimental joins.

schema.prisma

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

model User {
  id            String    @id
  name          String
  email         String
  emailVerified Boolean   @default(false)
  image         String?
  createdAt     DateTime  @default(now())
  updatedAt     DateTime  @updatedAt
  sessions      Session[]
  accounts      Account[]

  @@unique([email])
  @@map("user")
}

model Session {
  id        String   @id
  expiresAt DateTime
  token     String
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
  ipAddress String?
  userAgent String?
  userId    String
  user      User     @relation(fields: [userId], references: [id], onDelete: Cascade)

  @@unique([token])
  @@index([userId])
  @@map("session")
}

model Account {
  id                    String    @id
  accountId             String
  providerId            String
  userId                String
  user                  User      @relation(fields: [userId], references: [id], onDelete: Cascade)
  accessToken           String?
  refreshToken          String?
  idToken               String?
  accessTokenExpiresAt  DateTime?
  refreshTokenExpiresAt DateTime?
  scope                 String?
  password              String?
  createdAt             DateTime  @default(now())
  updatedAt             DateTime  @updatedAt

  @@index([userId])
  @@map("account")
}

model Verification {
  id         String   @id
  identifier String
  value      String
  expiresAt  DateTime
  createdAt  DateTime @default(now())
  updatedAt  DateTime @updatedAt

  @@index([identifier])
  @@map("verification")
}

The @@map directives keep Prisma model names in PascalCase while mapping to the lowercase table names Better Auth expects.

Applying migrations

After generating or editing your schema, run Prisma Migrate to apply the changes:

npx prisma migrate dev --name init

For production deployments:

npx prisma migrate deploy

Experimental joins

Enabling joins allows Better Auth to fetch related data in a single query instead of multiple round-trips. Endpoints such as /get-session and /get-full-organization see 2-3x latency improvements with high-latency databases.

auth.ts

export const auth = betterAuth({
  experimental: { joins: true },
});

Joins require @relation directives in your Prisma schema. Run npx auth@latest generate with the latest CLI to produce a schema that includes them.