Two migrations. -70% latency.
"We need to migrate the backend."
"But we can't stop production."
"And it needs to be done yesterday."
We had outgrown Express. Firestore was slow and expensive for what we asked of it.
Before touching anything, I evaluated the options: an updated Express, FastAPI, NestJS.
I prepared architecture templates, prototyped the key modules and got the team on board.
First, the API to NestJS. Then, the database from Firestore to PostgreSQL.
Zero downtime. Zero broken features. No "we'll fix it later" moments.
Result: over 70% lower API response times.
Legacy code isn't scary. Letting it grow is.
- TypeScript
- NestJS
- Express
- PostgreSQL
- Firestore