Prisma Security Guide: Safe Database Access in TypeScript

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TL;DR

TL;DR

Prisma prevents SQL injection by default through parameterized queries. The main risks are exposing your database URL, using unsafe raw queries with string interpolation, and returning too much data. Keep your connection string secure and validate input before queries.

Prisma is a TypeScript ORM that makes database access type-safe and developer-friendly. It's widely used in AI-generated applications because AI tools can scaffold Prisma schemas quickly. While Prisma provides good security defaults, there are still patterns that can introduce vulnerabilities.

Why Prisma Is Generally Safe

Prisma handles several security concerns automatically:

  • Parameterized queries prevent SQL injection in normal use
  • Type safety catches many errors at compile time
  • Connection pooling handles database connections efficiently
  • Migrations provide controlled schema changes

However, you can still introduce vulnerabilities through misconfiguration or unsafe patterns.

Common Prisma Security Issues

Critical: Raw Query Injection

Prisma's $queryRaw and $executeRaw can be vulnerable to SQL injection if you use string interpolation instead of tagged template literals. Always use the tagged template syntax.

Issue 1: Unsafe Raw Queries

This code is vulnerable to SQL injection:

Use tagged template literals instead:

Or better yet, use Prisma's query methods:

Issue 2: Exposed Database URL

Never put your database URL in frontend code:

Store it in environment variables:

Issue 3: Returning Too Much Data

Don't return entire objects when you only need specific fields:

Prisma Security Checklist

Connection Security

Use environment variables

  • DATABASE_URL should never be in code

Add .env to .gitignore

  • Never commit database credentials

Enable SSL

  • Add ?sslmode=require to connection string

Use connection pooling

  • Consider Prisma Data Platform for serverless

Query Security

Avoid raw queries

  • Use Prisma query methods when possible

Use tagged templates

  • For raw queries, use backtick syntax

Validate input

  • Check user input before passing to queries

Use select

  • Only return fields you need

Authorization

Filter by user

  • Always scope queries to the authenticated user

Check ownership

  • Verify user owns resource before update/delete

Input Validation Before Queries

Always validate and sanitize input:

Scoping Queries to Users

Always include user context in queries:

Use Prisma Middleware for Auth Checks

Consider using Prisma middleware to automatically add user filters to queries. This creates a safety net in case you forget to add authorization checks in individual queries.

Does Prisma prevent SQL injection?

Yes, Prisma's query methods automatically parameterize inputs, preventing SQL injection. However, if you use Prisma.$queryRaw or Prisma.$executeRaw with string interpolation instead of tagged template literals, you can still introduce SQL injection vulnerabilities. Always use the tagged template syntax for raw queries.

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How do I secure my Prisma connection string?

Store your DATABASE_URL in environment variables, never in code. Add your .env file to .gitignore. In production, use your hosting platform's secrets management. Enable SSL for database connections by adding ?sslmode=require to your connection string.

What are common Prisma security mistakes?

Common mistakes include: exposing the database URL in frontend code, using string interpolation in raw queries instead of tagged templates, not validating user input before queries, and returning entire database objects instead of selecting specific fields. Always validate input and only return the data you need.

Should I use Prisma in serverless?

Yes, but use connection pooling. Serverless functions can exhaust database connections quickly. Use Prisma Data Platform, PgBouncer, or your database provider's connection pooler (like Supabase's pooler or Neon's pooler) to manage connections efficiently.

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Prisma Security Guide: Safe Database Access in TypeScript