▶ Live demo: apps.charliekrug.com/circuitle
A daily logic-gate puzzle. Every day you get one truth table; your job is to build a circuit of AND / OR / NOT / XOR / NAND / NOR / XNOR gates that reproduces it using the fewest gates you can. Think Wordle, except the thing you are minimizing is boolean algebra instead of guesses.
The puzzle is the same for everyone (seeded by the UTC date), so your gate count is directly comparable to a friend's, and shareable without spoiling the circuit.
Programmers, CS and EE students, and daily-puzzle players who think in boolean logic and have already run through every word and geography Wordle spinoff. If you know what a NAND gate does and you like a puzzle that makes you reason instead of recall, this is built for you.
Open the live demo, then:
- Read today's Target table on the right. Each row is an input
assignment (
A,B,C) and the output it must produce. - Drag gates from the Gates dock onto the board, or place them from the keyboard.
- Click a signal source (an input pin or a gate output) then a target (a
gate input or the
OUTsink) to wire them. The truth table re-evaluates live after every change, marking each row pass or fail. - Turn every row green to win. Your score is the gate count, measured against the puzzle's computed par.
Sample share output (spoiler-free, Wordle-style):
Circuitle 2026-07-06 — 4 gates (+1)
That reads "4 gates, one under par." Lower is better.
- A fresh puzzle every day, seeded by the UTC date, identical for every player so scores compare directly.
- Live circuit simulation: every row of the truth table shows pass or fail within a frame of any wiring change, with no separate "run" button.
- Scoring against a real par: par is the provably minimal gate count for
that day's function, found by a Dijkstra-style search over the truth
table (see
src/par.ts), not a hand-waved estimate. - Full keyboard play: place a gate, wire two pins, and delete a gate all work from the keyboard, and rejected connections (a cycle, an output wired to an output) are shown rather than silently dropped.
- Game feel: gates snap to the grid, wires pulse when connected, an invalid drop shakes, and a solve sends current traveling through the circuit before the result card appears.
- Synthesized sound: every action tone is generated in WebAudio (no audio files), with a mute toggle that persists across reloads.
- Local best-score tracking per day, no account required.
npm install
npm run dev # local dev server
npm test # unit tests
npm run coverage # unit tests with a coverage report
npm run typecheck # tsc --noEmit
npm run lint # eslint
npm run build # production build to site/The code splits into a pure-logic layer (the circuit model, evaluator, par
search, and scoring, fully unit tested) and a thin Canvas/DOM layer that
renders it. See docs/ARCHITECTURE.md for the map,
docs/VISION.md for the design rationale, and
docs/DESIGN.md for the visual direction.
- TypeScript for the circuit model, evaluator, and app logic
- Canvas 2D for board rendering and interaction
- Vite for the dev server and static production builds
- Vitest with fast-check for unit and property-based tests
Ships as a static, self-contained site. No backend required.
MIT, see LICENSE.
More of Charlie's projects → apps.charliekrug.com