Foundation Base
Production readyFinancev1.0.0 · updated Jul 2, 2026
EX

Open Source Expense Tracker Template

Three-second logging, and a month view that tells the truth.

A fast expense logger with categories, a monthly budget, and a breakdown that shows exactly where the money went.

Runnable Agent-ready Install-ready Deploy-ready
foundationbase.app/demo/expense-trackerOpen full demo →

This is the real app, not a mockup. Whatever you enter in the demo stays in your browser and belongs to nobody.

What you get

One zip. Everything to own it.

Expense Tracker is built around one habit: log it before you forget it happened. Capture takes three fields, the month view rolls everything into category bars against your budget, and the math is computed from your entries — never typed in. Swap the categories, currency, or budget logic to match how you actually spend.

  • Three-field expense capture
  • Category filters
  • Monthly budget with remaining/over state
  • Category breakdown with bars
  • Computed totals — nothing hand-entered
expense-tracker.zipMIT
expense-tracker/├── app/the running Next.js app├── agent/START_HERE, PROJECT_MAP, RULES, RECIPES, TESTS, DEPLOY├── CLAUDE.mdread automatically by Claude Code├── AGENTS.mdread automatically by Codex├── .cursor/rules/loaded automatically by Cursor└── README.mdrun it, then make it yours

Inside the app

What the running app actually looks like
Expense Tracker: Quick capture
Quick capture — Description, amount, category — done.

Customize with AI

Your agent already knows this codebase.

Ships with CLAUDE.md, AGENTS.md, Cursor rules, and a full agent handbook — project map, safety rules, recipes, tests, and deploy notes.

Claude CodeCursorCodex

Prompts written against this app

Change the spending categories to match my real budget.
Add CSV export and import for my expense history.
Add a weekly spending view alongside the month view.
Add optional account sync later without changing the local-first default.

Run it

5 min to your own copy.

  1. 01Create your editable app copy and unzip it.
  2. 02Run npm install.
  3. 03Run npm run dev and open http://localhost:3000.
  4. 04Read /agent/START_HERE.md before customizing.
  5. 05Swap the local-first storage boundary for your own backend when ready.
Full walkthrough, including deploy and install →
Where your data lives

Expense entries stay in this browser by default.

No account, backend, bank connection, or cloud sync is included in the current package.

An agent can add exports, imports, or optional sync while keeping local capture fast.

Honest limitation

This package is standard-ready for Create My App and AI customization.

A full app-only PWA install route is not enabled yet for this app.

Verification receiptchecked Aug 2, 2026 at c11c184 · v1.0.0
Demo renderscaptured 2026-07-26, 35 KBpassed
Package installs and buildsinstalled, typechecked and built in 95s on node v24.13.0passed
Source package complete31 files, 55 KBpassed
Agent instructions included5 handoff files presentpassed
No network calls in app sourcestatic scan clean: no network calls, eval, or secrets in app sourcepassed
License matches the packageMIT, matching the file in the packagepassed

If this isn’t quite right

All Finance foundations →
finance · 5 min setupBudget PlannerA zero-based monthly budget planner with envelopes, real rollover balances, overspend warnings, and a safe-to-spend-per-day figure.finance · 5 min setupSubscription TrackerTrack every recurring charge, see your true monthly burn, and catch renewals before they catch you.finance · 5 min setupInvoice & EstimatesA billing document foundation for estimates, invoices, client approval, payment links, and clean PDF output.
How To Use Foundation BaseHow To Customize An App With AiDemo Link Vs Preview Link Vs App LinkHow To Deploy Your Own App LinkOpen Source App Templates

Take Expense Tracker and make it yours.

Free, MIT, 5 min to running. The demo above is exactly what lands in your folder.

Create My AppTry demo
Create My App