---
name: "Prisma vs Mongoose"
description: "Comprehensive comparison between Prisma and Mongoose for MongoDB"
when-to-use: "When evaluating MongoDB ODM options"
keywords: ["mongoose", "mongodb", "comparison", "odm"]
priority: 2
requires: ["prisma-7", "databases"]
related: ["vs-typeorm", "vs-sequelize", "mongodb"]
---

# Prisma vs Mongoose

## Feature Comparison Matrix

| Feature | Prisma | Mongoose |
|---------|--------|----------|
| **Databases** | MongoDB | MongoDB only |
| **Type Safety** | ✅ Full (generated) | ⚠️ Basic (plugins) |
| **Migrations** | Built-in | Manual |
| **Query Builder** | DSL | Chainable API |
| **Validation** | Prisma-level | Schema-based |
| **Middleware** | Limited | Powerful hooks |
| **Learning Curve** | ⭐ Easy | ⭐⭐ Moderate |
| **Bundle Size** | ~100KB | ~400KB |

## Key Differences

### Schema Definition

**Prisma: Unified declarative syntax (SOLID: SRP - schema separation)**
```prisma
// Module: prisma/schema.prisma
// Purpose: MongoDB schema definition (SOLID: SRP - schema only)
datasource db {
  provider = "mongodb"
  url      = env("DATABASE_URL")
}

model User {
  id    String  @id @default(auto()) @map("_id") @db.ObjectId
  email String  @unique
  name  String
  posts Post[]  // Relation to posts
}

model Post {
  id     String  @id @default(auto()) @map("_id") @db.ObjectId
  title  String
  userId String  @db.ObjectId
  user   User    @relation(fields: [userId], references: [id])
}
```

**Mongoose: Schema-based with embedded validation (SOLID: Mixes validation & structure)**
```typescript
// Module: src/models/User.ts
// Purpose: Schema definition with embedded validation (SOLID violation - mixing concerns)
import { Schema, model } from "mongoose";
import type { Document } from "mongoose";

/**
 * User interface for type safety
 * @interface IUser
 */
interface IUser extends Document {
  email: string;
  name: string;
  createdAt: Date;
}

/**
 * Mongoose schema with embedded validation
 * SOLID violation: Mixes schema, validation, and ORM concerns
 */
const userSchema = new Schema<IUser>({
  email: {
    type: String,
    unique: true,
    required: true,
    validate: { isEmail: true }, // Validation in schema
  },
  name: { type: String, required: true },
  createdAt: { type: Date, default: Date.now },
});

export const User = model<IUser>("User", userSchema);
```

### Queries

**Prisma: Type-safe queries (SOLID: DIP - abstraction layer)**
```typescript
// Module: src/queries/user.ts
// Purpose: Type-safe user queries (SOLID: SRP - query logic only)
import type { Prisma } from "@prisma/client";

/**
 * Find user by email with posts
 * Type safety guaranteed: Return shape is validated by compiler
 */
async function findUserWithPosts(
  prisma: Prisma.PrismaClient,
  email: string
) {
  return prisma.user.findUnique({
    where: { email },
    include: { posts: true },
  });
}
```

**Mongoose: Chainable with manual type safety (SOLID: Manual type annotation needed)**
```typescript
// Module: src/queries/user.ts
// Purpose: Document queries with chainable API
import type { Document } from "mongoose";
import type { IUser } from "../models/User";

interface UserWithPosts extends IUser {
  posts: Array<any>; // Manual relation typing required
}

/**
 * Find user by email with posts
 * Type safety NOT guaranteed - manual casting needed
 */
async function findUserWithPosts(
  email: string
): Promise<UserWithPosts | null> {
  return User.findOne({ email })
    .populate("posts") // Not type-checked
    .exec() as Promise<UserWithPosts | null>;
}
```

## Strengths & Weaknesses

### Prisma Advantages
- 🟢 Type safety out of the box
- 🟢 Simpler learning curve
- 🟢 Better IDE autocomplete
- 🟢 Built-in migrations

### Prisma Limitations
- 🔴 MongoDB-specific features limited
- 🔴 Fewer plugin/middleware options

### Mongoose Advantages
- 🟢 MongoDB expertise
- 🟢 Powerful middleware hooks
- 🟢 More MongoDB-native features
- 🟢 Larger ecosystem

### Mongoose Limitations
- 🔴 Weak type safety by default
- 🔴 Manual migrations
- 🔴 Higher complexity
- 🔴 Larger bundle size

## Validation Comparison

```typescript
// Prisma: Declarative validation
model User {
  email String @unique
  name  String
  age   Int?
}

// Mongoose: Schema validators
const userSchema = new Schema({
  email: { type: String, unique: true, required: true },
  name: { type: String, required: true },
  age: { type: Number, min: 0, max: 150 }
});
```

## When to Use

| Scenario | Best Choice | Reason |
|----------|------------|--------|
| New MongoDB project | Prisma | Better DX, type safety |
| Legacy Mongoose codebase | Mongoose | Less migration work |
| Need advanced validation | Mongoose | Built-in validators |
| Rapid development | Prisma | Faster to build |

## Migration Considerations

Mongoose projects typically require more effort to migrate due to:
- Complex schema validators → Prisma validation strategy
- Middleware/hooks → Application logic
- MongoDB-specific operations → Prisma equivalents
