https://ac-opensource.github.io/blog/ Engineering logs, essays, and field notes by Andrew Concepcion. en-us Thu, 26 Mar 2026 15:01:31 GMT https://ac-opensource.github.io/blog/2026-03-26-prompt-patterns-for-production-ready-code.html https://ac-opensource.github.io/blog/2026-03-26-prompt-patterns-for-production-ready-code.html Thu, 26 Mar 2026 00:00:00 GMT The prompt structures I use to get reliable code output: constraint framing, verification loops, and integration-first instructions. ai-workflowpromptingengineeringdeliveryqualitytechnical https://ac-opensource.github.io/blog/2026-03-26-e2e-and-visual-qa-for-personal-websites.html https://ac-opensource.github.io/blog/2026-03-26-e2e-and-visual-qa-for-personal-websites.html Thu, 26 Mar 2026 00:00:00 GMT A practical QA stack for personal sites using route-level E2E checks and Playwright screenshot loops to catch regressions early. qualitye2eplaywrightqafrontendtechnical https://ac-opensource.github.io/blog/2026-03-26-editable-blog-system-on-github-pages.html https://ac-opensource.github.io/blog/2026-03-26-editable-blog-system-on-github-pages.html Thu, 26 Mar 2026 00:00:00 GMT How to keep a blog editable with SQLite and tooling while deploying static pages for GitHub Pages compatibility and SEO. site-architecturesqlitegithub-pagesseocontent-systemtechnical https://ac-opensource.github.io/blog/2026-03-26-career-trajectory-platform-ownership.html https://ac-opensource.github.io/blog/2026-03-26-career-trajectory-platform-ownership.html Thu, 26 Mar 2026 00:00:00 GMT A framework for reading career growth through ownership depth, technical influence, and shipped outcomes rather than title progression. careerleadershipplatform-ownershipdeliveryengineering-growthtechnical https://ac-opensource.github.io/blog/2026-03-26-from-mobile-developer-to-ai-accelerated-engineer.html https://ac-opensource.github.io/blog/2026-03-26-from-mobile-developer-to-ai-accelerated-engineer.html Thu, 26 Mar 2026 00:00:00 GMT What actually changed in my day-to-day engineering: workflow became parallel, delivery got faster, and scope expanded from feature ownership to full system ownership. ai-workflowengineeringdeliveryscopesystems-thinkingtechnical https://ac-opensource.github.io/blog/2026-03-26-cognitive-profile-deep-dive.html https://ac-opensource.github.io/blog/2026-03-26-cognitive-profile-deep-dive.html Thu, 26 Mar 2026 00:00:00 GMT A practical deep dive on how Emergenetics and Harrison results translate into architecture decisions, delivery style, and collaboration behavior. emergeneticsharrisonparadoxself-awarenessleadershipreflection https://ac-opensource.github.io/blog/case-study-mystc-scale-and-reliability.html https://ac-opensource.github.io/blog/case-study-mystc-scale-and-reliability.html Wed, 05 Feb 2025 00:00:00 GMT How we delivered high-traffic telecom account flows with tighter performance budgets, multi-language support, and predictable release execution. MySTCAndroidKotlinTelecomwork https://ac-opensource.github.io/blog/2024-11-02-sunrise-trail-runs.html https://ac-opensource.github.io/blog/2024-11-02-sunrise-trail-runs.html Wed, 05 Feb 2025 00:00:00 GMT Family holidays in Auckland, a compressed South Island road trip, and the surprise of catching the Aurora Australis. TravelFamilyReflectionhobby https://ac-opensource.github.io/blog/2024-11-21-quiet-systems-reflection.html https://ac-opensource.github.io/blog/2024-11-21-quiet-systems-reflection.html Thu, 21 Nov 2024 00:00:00 GMT A personal essay about designing focus blocks, protecting rest, and keeping philosophy close to the shipping calendar. ReflectionPhilosophyCreative Processreflection https://ac-opensource.github.io/blog/case-study-ocbc-banking-experience.html https://ac-opensource.github.io/blog/case-study-ocbc-banking-experience.html Wed, 20 Nov 2024 00:00:00 GMT Delivery notes from a banking app environment where trust, performance, and safe iteration all matter simultaneously. OCBCFintechAndroidKotlinwork https://ac-opensource.github.io/blog/2024-10-08-running-ai-fleet-learnings.html https://ac-opensource.github.io/blog/2024-10-08-running-ai-fleet-learnings.html Tue, 08 Oct 2024 00:00:00 GMT An operations diary covering how we tuned prompts, instrumentation, and workflows to keep a multi-agent AI fleet shippable. AI OpsPrompt EngineeringTeam Processtechnical https://ac-opensource.github.io/blog/2024-09-14-film-photography-gallery.html https://ac-opensource.github.io/blog/2024-09-14-film-photography-gallery.html Sat, 14 Sep 2024 00:00:00 GMT Three frames from one trip, one ongoing experiment: motion, moon detail, and mountain light across different gear and shooting constraints. HobbyPhotographyhobby https://ac-opensource.github.io/blog/case-study-openpay-bnpl-experience.html https://ac-opensource.github.io/blog/case-study-openpay-bnpl-experience.html Sun, 01 Sep 2024 00:00:00 GMT How I improved checkout reliability and spend-limit UX for openpay through focused mobile flow and release hardening work. openpayfintechbnplandroidcheckoutwork https://ac-opensource.github.io/blog/case-study-solo-whitelabel-delivery-platform.html https://ac-opensource.github.io/blog/case-study-solo-whitelabel-delivery-platform.html Sat, 10 Aug 2024 00:00:00 GMT Scaling one codebase across multiple food brands while preserving brand-specific behavior and keeping deployment overhead manageable. SoloFood DeliveryAndroidWhitelabelwork https://ac-opensource.github.io/blog/case-study-owto-ride-hailing-platform.html https://ac-opensource.github.io/blog/case-study-owto-ride-hailing-platform.html Sat, 15 Jun 2024 00:00:00 GMT Leading full-stack mobile and backend delivery for a ride-hailing product focused on booking reliability and operational execution. OWTOMobilityAndroidiOSBackendwork https://ac-opensource.github.io/blog/2024-05-22-building-with-kotlin-and-swift.html https://ac-opensource.github.io/blog/2024-05-22-building-with-kotlin-and-swift.html Wed, 22 May 2024 00:00:00 GMT A quick reflection on pairing Compose Multiplatform with SwiftUI to deliver features natively. KMPSwiftUItechnical https://ac-opensource.github.io/blog/case-study-popslide-engagement-and-monetization.html https://ac-opensource.github.io/blog/case-study-popslide-engagement-and-monetization.html Thu, 30 Nov 2023 00:00:00 GMT Operational lessons from balancing retention, monetization, and product stability in an ad-and-task rewards app. PopslideAdtechAndroidExperimentationwork https://ac-opensource.github.io/blog/case-study-websafety-parental-controls.html https://ac-opensource.github.io/blog/case-study-websafety-parental-controls.html Thu, 22 Jun 2023 00:00:00 GMT Building parental control features with strict privacy and platform constraints, including hard technical limits on mobile operating systems. WebSafetySecurityParental ControlsAndroidwork https://ac-opensource.github.io/blog/case-study-projectbass-crowdsourced-network-mapping.html https://ac-opensource.github.io/blog/case-study-projectbass-crowdsourced-network-mapping.html Wed, 05 Oct 2022 00:00:00 GMT Community-built signal and bandwidth mapping designed to collect useful field data through volunteer contributions. ProjectBASSOpen SourceNetwork MappingKotlinwork