How to Choose the Right Database for Your Startup

The Database Decision

Your database choice is one of the most important technical decisions you'll make. According to DB-Engines rankings, PostgreSQL has overtaken MySQL as the most popular open-source database in 2025, while MongoDB leads the NoSQL category.

Relational vs NoSQL: The Basics

Relational Databases (SQL)

• PostgreSQL: The most advanced open-source database - used by 45% of developers
• MySQL: Battle-tested and widely supported - powers WordPress, Facebook
• SQLite: Perfect for embedded and small applications - 1 trillion+ active databases

NoSQL Databases

• MongoDB: Document-oriented, flexible schemas - 46,000+ customers
• Redis: In-memory, ultra-fast key-value store - sub-millisecond latency
• Cassandra: Distributed, high availability - handles petabytes of data

PostgreSQL: The Safe Choice

PostgreSQL is often the best default choice for startups. According to Timescale's 2024 State of PostgreSQL:

• 90% of PostgreSQL users would recommend it
• ACID compliance for data integrity
• JSONB support for flexible, indexed JSON data
• Full-text search built-in (no Elasticsearch needed for basic use)
• Extensions ecosystem: PostGIS, pgvector, TimescaleDB

Performance Benchmarks

MongoDB: When Flexibility Matters

Choose MongoDB when:

• Your schema changes frequently (rapid prototyping)
• You're dealing with unstructured data (logs, events)
• You need horizontal scaling from day one
• Your team is more comfortable with JSON/JavaScript

MongoDB Strengths

• Flexible schema: No migrations needed for schema changes
• Horizontal scaling: Built-in sharding
• Developer experience: Native JSON, intuitive queries
• Atlas Search: Built-in full-text search

Serverless Database Options

The serverless database market has exploded in 2025:

Neon (PostgreSQL)

• Branching: Git-like database branches for development
• Autoscaling: Scale to zero, pay for what you use
• Free tier: 0.5GB storage, generous compute

PlanetScale (MySQL)

• Branching: Safe schema migrations
• Vitess-powered: Battle-tested at YouTube scale
• Serverless: No connection pooling needed

Turso (SQLite)

• Edge-native: SQLite at the edge
• Embedded replicas: Local reads, global writes
• Lowest latency: Data close to users

Pricing Comparison (Hobby Tier)

Managed vs Self-Hosted

Managed Services (Recommended for Startups)

• Supabase: PostgreSQL with real-time, auth, and storage - open source
• PlanetScale: Serverless MySQL with branching
• MongoDB Atlas: Managed MongoDB with search
• Neon: Serverless PostgreSQL with branching

Self-Hosted

Lower costs at scale but requires DevOps expertise. Consider only when:

• You have dedicated DevOps resources
• Compliance requires data residency
• Cost optimization at massive scale (1M+ users)

Decision Framework

Choose PostgreSQL When

• Building a SaaS application
• Need complex queries and JOINs
• Want one database for everything
• Team has SQL experience

Choose MongoDB When

• Rapid prototyping phase
• Highly variable data structures
• Need horizontal scaling immediately
• Team prefers JavaScript/JSON

Choose MySQL When

• WordPress or PHP ecosystem
• Legacy system compatibility
• Simple CRUD operations
• Cost-sensitive (more hosting options)

Real-World Examples

Startups Using PostgreSQL

• Instagram: Started with PostgreSQL, still uses it
• Stripe: PostgreSQL for financial data
• Reddit: PostgreSQL for core data

Startups Using MongoDB

• Coinbase: MongoDB for crypto transactions
• Lyft: MongoDB for ride data
• Forbes: MongoDB for content

Our Recommendation

For most startups in 2025, start with PostgreSQL via Supabase or Neon:

1. Supabase if you want auth, real-time, and storage included
2. Neon if you want pure PostgreSQL with branching

Both offer generous free tiers and scale well. Only choose MongoDB if you have specific requirements that SQL can't meet efficiently.

Explore database options in our Tools directory or compare platforms with our Compare tool.

Sources

• DB-Engines Database Ranking
• Stack Overflow Developer Survey 2024
• Timescale State of PostgreSQL 2024
• PostgreSQL Documentation
• MongoDB Documentation