The loyalty engine
2019.201Points are integers. The hard part is time, and users who think faster than your rules.
Backend
tag:
backend
all tags →2019
2018
The week pgbouncer stopped being news
2018.193Transaction pooling, one SET that didn't stick, and a standup that moved on.
2017
Designing a wallet
2017.232What a digital wallet looks like underneath -- a balance, a ledger, idempotency keys, and the gap between moving money and moving money correctly.
The promocode engine
2017.201A rules engine that answers yes or no during checkout, with condition trees built by people who don't code.
2015
Graph queries for a social feed
2015.041Why a graph database was the only sane choice for a social feed where the interesting question isn't what your friends posted, but what your friends' friends are doing this Saturday.
2012
A fifty-line rate limiter
2012.249In-memory rate limiting as Express middleware. No Redis, no external service. Fifty lines, one file.
Connection pooling
2012.202The Node.js MySQL driver doesn't pool connections. Under load, you run out. Fifty lines with generic-pool fixes it.
URL mapping in Redis
2012.162Loading every product, category, and brand URL into a Redis hash at startup, and a middleware that rewrites requests before Express sees them.
Rolling your own search
2012.074Building catalog search with flattened MongoDB documents and application-side scoring when the proper tools don't exist yet.