Introduction
MySQL and PostgreSQL are the two most popular open-source relational databases in the world. Both are mature, reliable, and production-proven at massive scale. But they make different trade-offs, and picking the wrong one for your project can create real headaches down the road.
Here's the comparison I wish I'd had when I was starting out.
A quick history
MySQL was built for speed — originally optimised for simple reads in web applications. It powers WordPress, Shopify, and Twitter (at various points). PostgreSQL was built for correctness — it's been ACID-compliant since 1996 and prioritises data integrity over raw speed.
JSON support
PostgreSQL wins here convincingly. Its JSONB type stores JSON in a binary format that's fully indexable and supports powerful operators:
-- PostgreSQL: query inside JSON with an index
SELECT * FROM users WHERE metadata @> '{"role": "admin"}';
-- MySQL: JSON support exists but indexing is limited
SELECT * FROM users WHERE JSON_EXTRACT(metadata, '$.role') = 'admin';If your app stores semi-structured data, PostgreSQL's JSONB is far superior.
Full-text search
Both databases support full-text search, but PostgreSQL's implementation is more powerful — it supports stemming, lexeme weights, and custom dictionaries. MySQL's full-text search is simpler and faster for basic use cases.
-- PostgreSQL full-text search
SELECT * FROM posts
WHERE to_tsvector('english', title) @@ to_tsquery('nextjs & deployment');Performance
MySQL is generally faster for simple, high-volume read workloads — which is why it dominates in WordPress and e-commerce. PostgreSQL performs better for complex queries, joins, and analytical workloads.
For most modern web apps doing a mix of reads and writes, the performance difference is negligible.
ACID compliance & data integrity
PostgreSQL is stricter — it enforces constraints more aggressively and handles edge cases (like concurrent transactions) more correctly by default. MySQL is more lenient, which can lead to silent data corruption if you're not careful about your storage engine (always use InnoDB).
Ecosystem & tooling in 2026
- Prisma, Drizzle, Kysely — support both equally well
- Supabase — PostgreSQL only
- PlanetScale — MySQL only (now paid)
- Neon — PostgreSQL only (serverless)
- Railway, Render — both
When to choose MySQL
- You're building a WordPress-based project
- Your team already knows MySQL
- You need PlanetScale's branching workflow
- Simple CRUD app with high read volume
When to choose PostgreSQL
- You need complex queries, CTEs, or window functions
- You're storing JSONB/semi-structured data
- You want Supabase or Neon as your hosting platform
- You care about strict data integrity and correctness
Conclusion
In 2026, I default to PostgreSQL for all new projects. The ecosystem (Supabase, Neon, Drizzle) is stronger, the feature set is richer, and the data integrity guarantees are better. MySQL is still excellent — especially if you're in the WordPress/PHP world — but for modern JavaScript/TypeScript stacks, Postgres is the obvious choice.