CockroachDB
Distributed SQL database that survives outages — Postgres-compatible with a generous free tier
Free tier (10 GiB storage, 50M RUs), from $0 usage-based
MongoDB Atlas
Managed MongoDB in the cloud — document database with flexible schemas and a massive ecosystem
Free tier (512 MB), Dedicated from $57/mo
Neon
Serverless Postgres that scales to zero — you only pay when your database is actually being used
Free tier, Pro from $19/mo
PlanetScale
Serverless MySQL with git-like branching for safe schema changes
From $39/mo (free tier discontinued)
Supabase
Postgres database with built-in auth, storage, and real-time — the open-source Firebase alternative
Free tier, Pro from $25/mo
Turso
SQLite at the edge — embed databases close to your users with LibSQL
Free tier (9 GB storage, 500 databases), Scaler from $29/mo
Upstash
Serverless Redis and Kafka — pay per request, scale to zero when idle
Free tier, usage-based from $0.20/100K commands
Xata
Serverless database with full-text search, file attachments, and a spreadsheet-like UI built in
Free tier (15 GB data, 750 MB search), Pro from $24/mo