Posts about design, software architecture, AWS and AI tools, plus short field notes.https://jimzandueta.devhttps://jimzandueta.dev/blog/a-timezone-bug-that-moved-dates-back-a-dayhttps://jimzandueta.dev/blog/a-timezone-bug-that-moved-dates-back-a-dayStakeholders reported that saving a quote moved its date back by a day. The cause was a timezone mix-up I could never have seen from the Philippines, and the fix was one rule about how to store a date.Fri, 13 Nov 2026 00:00:00 GMThttps://jimzandueta.dev/blog/i-built-a-website-that-redesigns-itself-every-dayhttps://jimzandueta.dev/blog/i-built-a-website-that-redesigns-itself-every-dayMy site switches to a different design movement every day, twenty-eight of them. The hardest part was making each one look like itself and not like its neighbours.Fri, 13 Nov 2026 00:00:00 GMThttps://jimzandueta.dev/blog/i-realized-i-was-paying-an-ai-to-reread-my-stack-traces-and-what-i-did-to-fix-thathttps://jimzandueta.dev/blog/i-realized-i-was-paying-an-ai-to-reread-my-stack-traces-and-what-i-did-to-fix-thatThirty prompts into a feature, I noticed my AI coding agent was rereading my old stack traces and abandoned plans on every request. I built oowl, a workflow layer for OpenCode, so each role gets only the files and notes its job needs.Mon, 08 Jun 2026 00:00:00 GMThttps://jimzandueta.dev/blog/building-chart-for-tala-from-raw-indicator-data-to-something-you-can-actually-inspecthttps://jimzandueta.dev/blog/building-chart-for-tala-from-raw-indicator-data-to-something-you-can-actually-inspectI added a chart() method to tala, my TypeScript technical analysis library, so you can see its indicators against the price. It also gained a server mode that re-runs the indicators when you edit the data in the browser.Sat, 30 May 2026 00:00:00 GMThttps://jimzandueta.dev/blog/stop-using-your-most-expensive-ai-model-to-stamp-the-paperworkhttps://jimzandueta.dev/blog/stop-using-your-most-expensive-ai-model-to-stamp-the-paperworkI stopped sending every small coding task to a premium AI model and built oowl, an open-source workflow layer on OpenCode that gives each job the model it needs.Mon, 11 May 2026 00:00:00 GMThttps://jimzandueta.dev/blog/i-built-an-ai-app-that-gives-you-superpowers-but-makes-them-uselesshttps://jimzandueta.dev/blog/i-built-an-ai-app-that-gives-you-superpowers-but-makes-them-uselessMy entry for the DEV April Fools Challenge is an AI genie that grants the superpower you ask for, then adds one condition that makes it useless.Wed, 08 Apr 2026 00:00:00 GMThttps://jimzandueta.dev/blog/from-ai-chaos-to-team-flow-codex-boilerplate-that-actually-workedhttps://jimzandueta.dev/blog/from-ai-chaos-to-team-flow-codex-boilerplate-that-actually-workedMy team's AI agents wrote the same feature in a different style for every teammate. This is the .codex folder I put in a NestJS boilerplate to make Codex follow one set of rules and remember our decisions.Wed, 01 Apr 2026 00:00:00 GMThttps://jimzandueta.dev/blog/how-to-allow-users-to-upload-and-download-data-from-aws-s3-without-direct-access-using-pre-signed-urlshttps://jimzandueta.dev/blog/how-to-allow-users-to-upload-and-download-data-from-aws-s3-without-direct-access-using-pre-signed-urlsA note on using pre-signed URLs so users can download from and upload to a private S3 bucket without ever seeing your AWS keys.Sat, 24 Dec 2022 00:00:00 GMThttps://jimzandueta.dev/blog/generate-an-ssh-key-pairhttps://jimzandueta.dev/blog/generate-an-ssh-key-pairA quick note on creating a 4096-bit RSA SSH key pair with ssh-keygen, without overwriting the key you already have.Tue, 16 Aug 2022 00:00:00 GMThttps://jimzandueta.dev/blog/setup-your-git-profilehttps://jimzandueta.dev/blog/setup-your-git-profileA quick note on setting the name, email and editor Git uses for your commits, globally or for one project.Tue, 16 Aug 2022 00:00:00 GMThttps://jimzandueta.dev/blog/setup-your-ssh-configuration-filehttps://jimzandueta.dev/blog/setup-your-ssh-configuration-fileA quick note on using the SSH config file to give each host a short name and its own key, such as separate personal and work GitHub accounts.Tue, 16 Aug 2022 00:00:00 GMThttps://jimzandueta.dev/blog/macos-moving-your-notification-to-a-different-displayhttps://jimzandueta.dev/blog/macos-moving-your-notification-to-a-different-displayHow I got macOS notifications to show on my main display instead of my MacBook screen, by moving the menu bar in Display Arrangement.Fri, 08 May 2020 00:00:00 GMT