Stop Buying Expensive Databases. S3 Already Is One.
S3 is object storage — dumb, slow, eventually consistent. Yet engineers built a fully transactional, crash-safe key-value database on top of it using LSM trees, conditional writes, and fencing tokens. The real lesson isn’t about S3. It’s that the line between “storage” and “database” is a convention you build, not a law you obey. If you understand your invariants, the cheapest substrate is often enough.