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
Install Prisma and the Prisma Client
npm install @prisma/client
npm install --save-dev prisma
pnpm add @prisma/client
pnpm add -D prisma
yarn add @prisma/client
yarn add --dev prisma
bun add @prisma/client
bun add -d prisma
Configure the adapter
Import prismaAdapter from better-auth/adapters/prisma and pass a PrismaClient instance: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.
Schema generation is supported. Schema migration must be run separately through Prisma:
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.
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
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.
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.
