Notes on AI platform and agent infrastructure, distributed systems, and reliability — by Dimuthu Wickramanayake.https://billacode.orgen-gbhttps://billacode.org/blogs/why-mcp-not-rest-apishttps://billacode.org/blogs/why-mcp-not-rest-apisThe question comes up the moment you try to make an agent use your existing API. The answer isn't that REST is wrong — it's that REST was designed for a client who reads the docs at build time, and an LLM isn't that client.Mon, 03 Aug 2026 00:00:00 GMThttps://billacode.org/blogs/techniques-behind-a-persona-and-propensity-systemhttps://billacode.org/blogs/techniques-behind-a-persona-and-propensity-systemA field guide to the techniques that turn billions of behavioural events into per-user personas and forward-looking scores — identity resolution, RFM, quantile bucketing, time-share archetyping, temporal validation, leakage control, and transparent composite scoring.Mon, 06 Jul 2026 00:00:00 GMThttps://billacode.org/blogs/go-vs-nestjs-the-backend-decision-youll-thank-yourself-for-laterhttps://billacode.org/blogs/go-vs-nestjs-the-backend-decision-youll-thank-yourself-for-laterA practical comparison for engineers who've felt the growing pains of Node.js at scale — with real numbers, honest tradeoffs, and a story about a Cloud Function that forced the question.Sat, 25 Apr 2026 00:00:00 GMThttps://billacode.org/blogs/saga-pattern-in-gamification-systemshttps://billacode.org/blogs/saga-pattern-in-gamification-systemsHow reactive sagas keep complex gamification workflows decoupled, resilient, and maintainable — and why the tradeoffs are worth it.Thu, 16 Apr 2026 00:00:00 GMThttps://billacode.org/blogs/import-aware-cicd-for-firebase-cloud-functionshttps://billacode.org/blogs/import-aware-cicd-for-firebase-cloud-functionsIf you have a monorepo with many Cloud Functions, setting up CI/CD can feel like something to avoid. In this guide I'll show a better approach: selective deployment using static import analysis, without any complex monorepo tooling like Bazel or Nx.Sat, 11 Apr 2026 00:00:00 GMThttps://billacode.org/blogs/building-multi-tenant-microservices-on-kuberneteshttps://billacode.org/blogs/building-multi-tenant-microservices-on-kubernetesA hands-on guide to production-grade microservices with namespace-level tenant isolation, mTLS, observability, and a React dashboard — all running locally on kind.Sat, 28 Mar 2026 00:00:00 GMThttps://billacode.org/blogs/living-llm-neurotransmitter-memoryhttps://billacode.org/blogs/living-llm-neurotransmitter-memoryHow I drew on neuroscience to give a locally-running Llama 3.1 persistent memory, a personal knowledge graph, and the ability to learn from its own conversations.Thu, 19 Mar 2026 00:00:00 GMThttps://billacode.org/blogs/traditional-software-engineering-jobs-are-finishedhttps://billacode.org/blogs/traditional-software-engineering-jobs-are-finishedFor the first time after long resisting letting AI agents do full changes to a codebase, this weekend I did a project using Claude Code and didn't write a single line of code.Sat, 28 Feb 2026 00:00:00 GMThttps://billacode.org/blogs/handling-rpc-exceptions-in-nestjs-microserviceshttps://billacode.org/blogs/handling-rpc-exceptions-in-nestjs-microservicesHow to properly handle RPC exceptions when communicating between NestJS microservices.Wed, 22 Oct 2025 00:00:00 GMThttps://billacode.org/blogs/nestjs-microservice-to-microservice-communication-using-rpchttps://billacode.org/blogs/nestjs-microservice-to-microservice-communication-using-rpcSo you split your giant monolith into microservices. Now how do they talk to each other? Here's how to use RPC in NestJS.Fri, 17 Oct 2025 00:00:00 GMThttps://billacode.org/blogs/my-recycling-app-did-3-pivots-and-0-recycles-a-post-mortemhttps://billacode.org/blogs/my-recycling-app-did-3-pivots-and-0-recycles-a-post-mortemI was gonna save the planet. With code. Here's how zylobin failed spectacularly.Sat, 11 Oct 2025 00:00:00 GMThttps://billacode.org/blogs/this-is-fine-how-disabling-caching-can-set-your-database-ablazehttps://billacode.org/blogs/this-is-fine-how-disabling-caching-can-set-your-database-ablazeA cautionary tale from the trenches of application development about what happens when you disable caching to fix a bug.Sat, 11 Oct 2025 00:00:00 GMThttps://billacode.org/blogs/your-laptops-ai-superpower-is-kinda-dumb-compared-to-real-apishttps://billacode.org/blogs/your-laptops-ai-superpower-is-kinda-dumb-compared-to-real-apisOr: How I Learned to Stop Worrying and Love the Cloud.Fri, 10 Oct 2025 00:00:00 GMThttps://billacode.org/blogs/i-built-a-website-because-sri-lankan-banks-wont-credit-card-deals-aggregatorhttps://billacode.org/blogs/i-built-a-website-because-sri-lankan-banks-wont-credit-card-deals-aggregatorTired of missing credit card promotions in Sri Lanka, I scraped 50 bank websites and built CardPromotions.org — using Python, Playwright, and local AI.Tue, 07 Oct 2025 00:00:00 GMThttps://billacode.org/blogs/firebase-dynamic-links-deprecated-implement-one-in-househttps://billacode.org/blogs/firebase-dynamic-links-deprecated-implement-one-in-houseFirebase Dynamic Links are deprecated. Here's how to build your own deferred deep link system in-house.Tue, 10 Jun 2025 00:00:00 GMThttps://billacode.org/blogs/creating-a-vod-application-like-netflix-amazon-prime-using-aws-media-converter-shttps://billacode.org/blogs/creating-a-vod-application-like-netflix-amazon-prime-using-aws-media-converter-sHow to design and build a video-on-demand service using AWS MediaConvert, S3, and CloudFront.Sun, 23 Feb 2025 00:00:00 GMThttps://billacode.org/blogs/estimating-bigquery-result-row-count-without-running-the-whole-queryhttps://billacode.org/blogs/estimating-bigquery-result-row-count-without-running-the-whole-queryHow to estimate BigQuery result count without running the full query using dry run.Mon, 27 Jan 2025 00:00:00 GMT