Lucas Winther
92e6b763f2
- AGENTS.md §1: reworded the "no horizon" invariant now that a parameter literally named horizonMonths exists. Nothing is stored — ExpectedBand's horizon only widens how far one read-only walk looks before the result is thrown away — but the old wording read as a contradiction to the next reader. The no-materialisation rule itself is unchanged. - DECISIONS.md: added the "archived mirrors endedFrom" entry that was missing, including the previously-undocumented corollary that a future-dated cancellation dims the row immediately even though the bill keeps projecting until endedFrom. - docs/specs/2026-09-03-recurring-costs-design.md §10-11: updated to describe the shipped UI — the "Coming up" group, the Ends column, the two coherence checks that gate a coming-up row (X1, X3), and the tests that now cover all of it.
Budget 2.0
A personal budgeting PWA. Envelope-style monthly budgets with rollover, split purchases, finance plans, multi-currency, and JSON/ODS export. All data lives in your browser — there is no server and no account.
Development
bun install
bun run dev # dev server with hot reload, on :3000
bun test # run the test suite
bun run build # production build into dist/
Self-hosting with Docker
docker build -t budget2 .
docker run --rm -p 3000:3000 budget2
To serve from a subpath, build and run with BUN_PUBLIC_BASE_PATH:
docker build -t budget2 --build-arg BUN_PUBLIC_BASE_PATH=/budget/ .
docker run --rm -p 3000:3000 -e BUN_PUBLIC_BASE_PATH=/budget/ budget2
GitHub Pages
Pushing to main builds and deploys to Pages automatically, using
/<repository-name>/ as the base path. Enable Pages with "GitHub Actions" as
the source in the repository settings.
Your data
Everything is stored in this browser's IndexedDB. Export regularly from Settings → Your data: the JSON export is both your backup and how you move your budget to another device.
Both destructive actions there — Import, and "Reset everything" — download a backup of your current data before replacing it, and abort if that download fails. Reset puts the app back to a brand-new install: the three starter posts, the DKK/USD/EUR currency table, this month at zero income, no purchases.
Known limitations
- Data is per-browser. There is no account and no sync. If you clear this browser's site data, or move to a different browser or device, your budget is gone unless you exported it first. The JSON export is not just a nice-to-have backup — it is the only way to move a budget between devices.
- Installing and offline use are unverified. The manifest ships the SVG plus 192×192 and 512×512 PNG icons, and the service worker demonstrably installs, activates and precaches every asset — but nobody has yet confirmed that Chrome offers its "Install app" prompt, or loaded the app with the network actually cut. It works as a regular tab regardless.
Documentation
docs/ARCHITECTURE.md— layers, data flow, and why the non-obvious choices are what they are.docs/PRODUCT.md— who this is for and what must never break.AGENTS.md— the rules for changing this codebase, and the test that catches each one when broken.CLAUDE.mdandGEMINI.mdpoint at it.docs/DECISIONS.md— an index of the choices that shaped the app, and what each was chosen over.docs/TODO.md— what is still queued.docs/specs/— one design document per piece of work, each recording the alternatives that were rejected.docs/plans/— task-by-task implementation plans.