D1

D1 is SQLite hosted on Cloudflare’s edge, and the pitch is seductive: a real relational database with zero-config provisioning, priced nearly free, right next to your Workers. For a prototype or a hobby project, the experience genuinely is that easy.

Production is a different conversation. It doesn’t scale: every database is a single writer with hard per-database size caps, so any real workload turns into manual sharding across databases — at which point you’ve rebuilt the hard parts of a distributed database yourself, on top of a product that wasn’t designed to help you. And the error rate isn’t there yet: transient internal errors are frequent enough that every D1 call in production needs retry wrapping and alerting.

It sits on Durable Objects storage under the hood, which means it inherits that platform’s operational characteristics too. Great for demos, proofs of concept, and per-tenant toy data. I would not put a production system of record on it today.