Prem Poddar, writingPosts and guides about the apps I build.https://prempoddar.is-a.dev/Keeping a Mac awake with the lid closed, without leaving it brokenhttps://prempoddar.is-a.dev/writing/caffeinatecat-lid-closed/https://prempoddar.is-a.dev/writing/caffeinatecat-lid-closed/Why lid-closed mode needs root, how CaffeinateCat asks for it once for exactly two commands, and the five separate things that make sure your Mac can always sleep again.Tue, 03 Nov 2026 12:06:00 GMTHow OAF opens almost any file, and saves without breaking ithttps://prempoddar.is-a.dev/writing/oaf-one-app-every-file/https://prempoddar.is-a.dev/writing/oaf-one-app-every-file/Detecting file types from their bytes instead of their names, a spreadsheet engine with loop detection, and why OAF patches Word and Excel files instead of rewriting them.Tue, 03 Nov 2026 12:05:00 GMTAn arrow that admits when it doesn't knowhttps://prempoddar.is-a.dev/writing/loadstone-honest-arrow/https://prempoddar.is-a.dev/writing/loadstone-honest-arrow/How Loadstone turns noisy GPS into a pin with an honest radius, keeps a compass arrow steady without making it slow, and fits a place on Earth into seven silly words.Tue, 03 Nov 2026 12:04:00 GMTSearching 16,000 packages in 3 ms per keystrokehttps://prempoddar.is-a.dev/writing/brewlight-homebrew-search/https://prempoddar.is-a.dev/writing/brewlight-homebrew-search/How Brewlight's search works, from byte buffers shaped so every kind of match is one memmem call, to a ranking packed into a single integer, to opening instantly by not asking brew.Tue, 03 Nov 2026 12:03:00 GMTEight phones, one song, the same millisecondhttps://prempoddar.is-a.dev/writing/duet-music-in-sync/https://prempoddar.is-a.dev/writing/duet-music-in-sync/How Duet finds other phones with six words and no server, estimates another phone's clock the way NTP does, and keeps playback in step by easing speed instead of jumping.Tue, 03 Nov 2026 12:02:00 GMTA messenger where the phones are the networkhttps://prempoddar.is-a.dev/writing/librechat-mesh-messaging/https://prempoddar.is-a.dev/writing/librechat-mesh-messaging/How LibreChat floods messages across a Bluetooth mesh, holds them for a day when there's no path yet, and starts Signal-style encrypted chats with no server to hand out keys.Tue, 03 Nov 2026 12:01:00 GMTA chat server that fits in your pockethttps://prempoddar.is-a.dev/writing/campfire-phone-hosted-chat/https://prempoddar.is-a.dev/writing/campfire-phone-hosted-chat/How Campfire runs a Ktor server on one phone for everyone nearby, keeps every chat rule in one class that never touches a socket, and stops a pasted link from probing your router.Tue, 03 Nov 2026 12:00:00 GMT