Working Memory

Try the live demo — no signup; you get your own throwaway board pre-loaded with three weeks of history, so the time machine has somewhere to go. (Free-tier host: the first load after an idle spell takes about a minute.)

The problem

For years I kept one perpetually rewritten note — today’s priorities at the top, things I was waiting on, a brain-dump at the bottom. It worked until I asked it a question it couldn’t answer: what was I actually worried about three weeks ago? The note only ever knew now; every rewrite quietly destroyed the previous me. Todo apps don’t fix this either. Trello, Notion and Linear keep track of current state well; they just don’t keep the earlier versions of it around.

What I built

A small kanban-style board (Today · Focus · Waiting · Backlog · Brain Dump, plus a pinned daily note) where every change to every card is recorded in an append-only event log. The board shows now; the time machine scrubs backward through every moment the board ever changed and re-renders it as it was — read-only, drill-down and all. Sub-cards nest to arbitrary depth with their own histories, daily-repeating tasks reset at local midnight without deleting anything, and multi-select drag plus undo keep it quick enough to use every day.

On a phone it’s a separate layout rather than the desktop board at 375px — one vertical feed, a paged Lists screen, and bottom sheets for everything else — and adding it to the iOS Home Screen also turns on Web Push notifications, which iOS only allows for installed web apps. The repo README covers both.

How it works

History is enforced by the database, not the app. Every insert or update on items fires a SQLite trigger that appends to item_events — so any client (the desktop board, the phone app, a script) records history just by writing. Time travel is a pure function that replays events backward from now. History isn’t a feature some code path can forget; it’s a property of the storage layer.

Durability without paying for it. The hosted instance runs on Render’s free tier with deliberately no persistent disk: Litestream continuously replicates the SQLite database to a Backblaze B2 bucket and restores it on every boot, which means every deploy is also a disaster-recovery drill. Daily automated pulls keep a local backup, and an uptime worker tames free-tier cold starts.

Multi-tenancy in one file. All accounts live in a single replicated SQLite database, scoped per-user in every query, with stateless HMAC cookie sessions. Anonymous visitors get isolated, rate-limited, auto-expiring demo boards seeded with fabricated-but-consistent history — the same app, no signup.