SQLite vs PostgreSQL: When to Use Each

Embedded simplicity vs full-featured power.

The Fundamental Difference

SQLite is an embedded database. It runs inside your application as a library—no server, no configuration, just a single file.

PostgreSQL is a client-server database. It runs as a separate process, handles multiple connections, and offers advanced features.

This shapes everything about when to use each.

SQLite Strengths

Zero Configuration

SQLite just works:

PYTHON

import sqlite3
conn = sqlite3.connect('app.db')  # Creates file if it doesn't exist
cursor = conn.cursor()
cursor.execute('CREATE TABLE users (id INTEGER PRIMARY KEY, name TEXT)')

No server to install, no ports to configure, no authentication to set up.

Single File

Your entire database is one file. Back it up by copying the file. Deploy by shipping the file. Simple.

BASH

# Backup
cp app.db app.db.backup

# Deploy
scp app.db server:/var/data/

Perfect for Embedded Use

Desktop applications
Mobile apps (iOS, Android)
Browser storage (via WebSQL or WASM)
IoT devices
CLI tools

Surprisingly Fast

For single-user, read-heavy workloads, SQLite is often faster than PostgreSQL because there's no network overhead or client-server communication.

Great for Development

Start with SQLite for prototyping, migrate to PostgreSQL later if needed:

PYTHON

# Development
DATABASE_URL = "sqlite:///dev.db"

# Production
DATABASE_URL = "postgresql://user:pass@host/db"

PostgreSQL Strengths

Concurrent Users

PostgreSQL handles thousands of simultaneous connections. SQLite has a single-writer limitation—only one write at a time.

SQL

-- PostgreSQL: Multiple users can write simultaneously
-- SQLite: Writers block each other

Advanced Features

PostgreSQL has features SQLite doesn't:

Full-text search with ranking and stemming
JSONB with indexing and operators
PostGIS for geospatial data
Window functions (SQLite has basic support)
CTEs with recursive queries
Materialized views
Stored procedures in multiple languages
Row-level security

Data Integrity

PostgreSQL is stricter about data types and constraints:

SQL

-- PostgreSQL: This fails if email isn't unique
INSERT INTO users (email) VALUES ('alice@example.com');

-- SQLite: More permissive by default, constraints need explicit enforcement

Scalability

Replication: PostgreSQL supports streaming replication for read replicas
Connection pooling: PgBouncer handles thousands of connections
Partitioning: Split large tables across storage

Concurrent Writes

PostgreSQL uses MVCC for true concurrent writes. Multiple users can write to different rows simultaneously without blocking.

Direct Comparison

| Feature | SQLite | PostgreSQL | |---------|--------|------------| | Setup | Zero config | Server installation | | Deployment | Single file | Client-server | | Concurrent writes | One at a time | Many simultaneously | | Concurrent reads | Unlimited | Unlimited | | Max database size | 281 TB (theoretical) | Unlimited | | Full-text search | Basic | Advanced | | JSON support | Good | Excellent (JSONB) | | Geospatial | Limited | PostGIS | | Replication | Manual | Built-in | | Best for | Embedded, single-user | Multi-user, web apps |

When to Choose SQLite

Embedded applications — Desktop apps, mobile apps, CLI tools
Single-user applications — Personal tools, local-first apps
Prototyping — Quick development without server setup
Edge computing — IoT devices, edge servers
Test databases — Fast, isolated test environments
Read-heavy workloads — Configuration, caching, logs
Small to medium websites — Yes, really—SQLite can handle more than you'd think

SQLite Can Handle More Than You Think

SQLite isn't just for toys. It handles:

Tens of thousands of requests per second (read-heavy)
Databases up to terabytes
Millions of rows

Many production apps use SQLite successfully. The SQLite website itself runs on SQLite.

When to Choose PostgreSQL

Multi-user web applications — SaaS, e-commerce, social apps
High write concurrency — Many users writing simultaneously
Complex queries — Analytics, reporting, business intelligence
Geospatial data — Maps, location-based features
Strict data integrity — Financial systems, healthcare
Horizontal scaling — Read replicas, connection pooling
Advanced features — Full-text search, JSONB, row-level security

The Hybrid Approach

You can use both:

PYTHON

# Local cache in SQLite
import sqlite3
cache_db = sqlite3.connect('cache.db')

# Main data in PostgreSQL
import psycopg2
main_db = psycopg2.connect(DATABASE_URL)

Or use SQLite for development and PostgreSQL for production—most ORMs support both.

Migration Path

Starting with SQLite and outgrowing it? Migration is straightforward:

Export from SQLite:

BASH

sqlite3 app.db .dump > dump.sql

Adjust syntax (some differences in CREATE TABLE, data types)
Import to PostgreSQL:

BASH

psql -d newdb -f dump.sql

Tools like pgloader automate this.

Performance Comparison

SQLite is faster for:

Single-user reads
Simple queries without network overhead
Small datasets that fit in memory
Applications on the same machine as the database

PostgreSQL is faster for:

Concurrent writes
Complex joins on large datasets
Queries that benefit from advanced indexing
Workloads with many simultaneous users

Quick Decision Framework

Use SQLite if:

Single user or few users
Embedded in application
Simplicity is priority
No server infrastructure available

Use PostgreSQL if:

Multiple concurrent users
Web application backend
Need advanced features
Scaling requirements

Start with SQLite, switch to PostgreSQL when:

Write conflicts become an issue
You need features SQLite lacks
You're adding multiple application servers

Summary

SQLite and PostgreSQL aren't competitors—they're tools for different jobs. SQLite excels at embedded, single-user scenarios where simplicity matters. PostgreSQL excels at multi-user, server-based scenarios where features and concurrency matter.

Many projects can start with SQLite and migrate to PostgreSQL if needed. The important thing is understanding the trade-offs and choosing based on your actual requirements, not assumptions about what a "real" database should be.