S M Al Hasib — WritingSoftware engineering and other miscellaneous, by S M Al Hasib.https://smalhasib.com/Cutting RAG response latency 70%: what actually moved the needlehttps://smalhasib.com/writing/cutting-rag-latency-70/https://smalhasib.com/writing/cutting-rag-latency-70/Six weeks, four false starts, one boring fix. A field report on what we actually changed to get from 30s to 6–11s.Sat, 18 Apr 2026 00:00:00 GMTRAGLatencyPostmortemMigrating a RAG stack from LangChain.js to Python — and whyhttps://smalhasib.com/writing/langchain-js-to-python/https://smalhasib.com/writing/langchain-js-to-python/We didn't move because Python was faster. We moved because the JS ecosystem was outpacing us in the wrong direction.Mon, 02 Mar 2026 00:00:00 GMTPythonLangChainMigrationShrinking a chat widget 80% by dropping the UI libraryhttps://smalhasib.com/writing/shrinking-chat-widget-80/https://smalhasib.com/writing/shrinking-chat-widget-80/When the dependency carrying you starts costing you Core Web Vitals on someone else's site, it's time to write the components yourself.Tue, 10 Feb 2026 00:00:00 GMTSveltePerformanceBundles