Writing5 essays
Writing
Incident write-ups and design notes, mostly about things that looked fine and weren't.
Code in these posts is written for the post and simplified. None of it is an employer's source.
- 01How a GST Returns Dashboard Became a Sub-15ms ReadGST return status queries went from 3,000ms+ to sub-15ms at peak load by reading a precomputed projection that filing writers keep fresh through domain events. Requirements, options and the update path.
- 02The Redis Namespace Bug Behind a Broken Processing PipelineTwo services used the same BullMQ queue name under different Redis key prefixes, so every OCR extraction result was enqueued where nothing would ever read it. An incident write-up.
- 03When HTTP 200 Still Means Your Integration FailedFour ways a GST portal integration lost or corrupted data while every request succeeded — a case-sensitive parameter, an unechoed field, a delegated rule and an over-broad sum — and how each was closed.
- 04Why Long-Running Workflow Updates Moved to a Durable SSE StreamReplacing several ephemeral SSE channels with one table-backed notification stream — 25-second heartbeats, Last-Event-ID replay and runId correlation across async workflows. A walkthrough from the wire up.
- 05Why RAG Shouldn't Retrieve EverythingIn BARA, retrieval is three separate decisions — whether, from where and how much, then which chunks — made by deterministic rules before a vector is ever compared. A research note with the code.