What is Monch?

Monch is a lightweight MongoDB ODM (Object Document Mapper) for TypeScript that combines the power of Zod validation with MongoDB operations. It provides a type-safe, developer-friendly way to work with MongoDB while ensuring data integrity through schema validation.

Why Monch?

The Problem

Working with MongoDB in TypeScript often involves:

• Manual type definitions that can drift from actual data
• No validation at the database boundary
• Tedious BSON serialization for frameworks like Next.js
• Boilerplate for common patterns like timestamps and pagination

The Solution

Monch addresses these issues with:

• Zod Schemas as Source of Truth - Your schema defines both validation rules and TypeScript types
• Automatic Validation - Documents are validated before insert, with partial validation on updates
• Built-in Serialization - Convert BSON types to JSON-safe values with a single .serialize() call
• Zero Configuration - Set MONGODB_URI and start coding

Core Principles

1. Validation at the Boundary

Monch validates data at the database boundary—when documents enter MongoDB. This catches errors early and ensures data consistency:

// Invalid data is rejected before reaching MongoDB
await Users.insertOne({
  name: '',  // Throws: String must contain at least 1 character
  email: 'not-an-email',  // Throws: Invalid email
});

2. Type Safety Throughout

Types flow from your Zod schema through queries to serialized output:

const Users = collection({
  schema: {
    _id: field.id(),
    name: field.string(),
    email: field.email(),
  },
  timestamps: true,
});

// TypeScript knows the shape
const user = await Users.findOne({ email: 'alice@example.com' });
// user: { _id: ObjectId, name: string, email: string, createdAt: Date, updatedAt: Date } | null

const serialized = user?.serialize();
// serialized: { _id: string, name: string, email: string, createdAt: string, updatedAt: string }

3. Progressive Enhancement

Monch stays out of your way. Use as much or as little as you need:

// Basic: Just schema and name
const Simple = collection({
  name: 'simple',
  schema: { _id: field.id(), value: field.string() },
});

// Full-featured: Timestamps, hooks, methods, indexes
const Advanced = collection({
  name: 'advanced',
  schema: { /* ... */ },
  timestamps: true,
  indexes: [{ key: { email: 1 }, unique: true }],
  hooks: { beforeInsert: (doc) => ({ ...doc, normalized: true }) },
  methods: { fullName: (doc) => `${doc.first} ${doc.last}` },
});

Comparison

Feature	Monch	Mongoose	Prisma
TypeScript-first	✅	Partial	✅
Zod validation	✅	❌	❌
Zero config	✅	❌	❌
Serialization helpers	✅	❌	❌
Schema file required	❌	❌	✅
Code generation	❌	❌	✅
Bundle size	~15KB	~800KB	~2MB

Next Steps

• Getting Started - Install and create your first collection
• Schema Definition - Learn about defining schemas
• CRUD Operations - Query, insert, update, and delete