For modern and handy, here are the best options:
Supabase (most popular choice)
- PostgreSQL under the hood, but with a clean dashboard
- Built-in auth, real-time subscriptions, storage
- Free tier is generous
- Works seamlessly with Next.js
- Easy to set up environment variables in Vercel
Neon
- Managed PostgreSQL, very lightweight
- Excellent free tier with good limits
- Serverless-friendly (scales to zero)
- Minimal setup needed
MongoDB Atlas
- If you prefer NoSQL/document-based
- Free tier available
- Good for rapid prototyping
- Simpler schema flexibility
Firebase (if you want the most "hands-off")
- Real-time database, auth, hosting all included
- Quickest to get running
- Less control over database structure
- Can get expensive at scale
My recommendation: Supabase is the sweet spot—it's PostgreSQL (reliable, powerful), but wrapped in a modern, developer-friendly interface. The free tier is practical, it integrates well with Vercel, and you get extras like auth and real-time out of the box.
In Codespace, you'd connect via connection string; in Vercel, you paste that same string as an environment variable. Both handle it transparently.
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PlanetScale is a Y Combinator startup (S19) that fits this use case perfectly.
PlanetScale details:
- MySQL-compatible database (serverless)
- Built for scale from the start
- Free tier is solid
- Vercel integration is seamless (they work well together)
- Branch-based development (like git for databases)
- Great for modern web apps
Why it's good for your setup:
- Serverless architecture matches Vercel's model
- Easy environment variable setup in Vercel
- MySQL is widely supported; any Node/Next.js library works
- The branching feature is handy for development
Other YC databases worth noting:
- Neon (not YC, but backed by top VCs) - PostgreSQL serverless
- Clerk (YC S21) - focuses on auth, pairs well with any database
Reality check: PlanetScale was solid, but Supabase (not YC) has become the de facto standard in the Next.js/Vercel ecosystem because PostgreSQL is more feature-rich and the free tier is more generous. PlanetScale's free tier got more limited over time.
If you specifically want a YC startup, PlanetScale is your answer—it's production-ready and works great with Codespace + Vercel. Just check their current pricing since they've made changes.