Circuitcaster is a free, browser-based PCB footprint designer that runs on your phone, tablet, or computer. Design pad patterns for any chip or connector on a touch-friendly dot grid, save them to your Library, and export to KiCad or any downstream tool.
Pick a pitch (2.54mm / 0.1 inch is the default, others are one tap away). Set your board width and height. Tap dots to place pads in numerical order. Nudge sub-grid offsets, paint pins by role, label them by signal name. Save the footprint to your Library so you can drop it into any future project.
Every other PCB tool assumes you're at a desk with a mouse. Circuitcaster was designed the other way around — for a phone in a hand, a tablet in a coffee shop, an S Pen on a couch. Ideas hit you when they hit you. The tool should be there when they do.
Circuitcaster exports a self-describing dotgame.footprint.v3 JSON. Every pad carries both KiCad-centered coordinates (origin at the component center, the KiCad convention) AND board-local coordinates. Every export also embeds an _ai_briefing so any downstream AI can consume it without additional context. A short recipe converts to .kicad_mod footprint files ready to drop into a KiCad library.
Circuitcaster is the first PCB tool built for the AI-driven browser era. The site hosts a machine-readable manual at app.circuitcaster.com/llms.txt and exposes a JavaScript driving surface at window.CIRCUITCASTER. Any browser-driving AI (Claude in Chrome, ChatGPT Operator, Gemini in Chrome, Perplexity Comet) can read the manual and design a footprint end-to-end from a naked prompt. Give your AI a chip name and a datasheet URL and let it drive.
See the case study where Claude Opus 4.8 designed a solar-powered USB phone charger from one paragraph — 12 components, complete BOM, wired and labeled.
A PCB footprint is the physical pad pattern a component solders onto — the copper landing area for each pin of a chip or connector, plus the outline of the part's body. Circuitcaster lets you design this pad layout by tapping dots on a 2.54mm (or any other pitch) grid.
Open app.circuitcaster.com in any modern browser, no signup needed. Set your pitch, set the board dimensions, and tap dots to place pads. Save to your Library. Export as JSON or drive it via AI. Free forever on the web.
Yes — this is Circuitcaster's core strength. It's designed touch-first for phones and tablets, with S Pen / Apple Pencil support. Start on your phone, finish on your computer — everything syncs.
Yes. Circuitcaster exports a self-describing JSON that includes KiCad-centered coordinates. A short recipe converts to .kicad_mod footprint files. See the AI manual at /llms.txt for the full pipeline.
Yes. This is what makes Circuitcaster unique. Point your AI (Claude in Chrome, ChatGPT Operator, Gemini in Chrome) at app.circuitcaster.com, prompt "design an ATtiny85 DIP-8 footprint," and watch it build. Zero prompt engineering required — the site's /llms.txt tells the AI everything it needs.
Yes. The web app is free with no signup, no download, and (currently) no library cap. A paid phone app is on the roadmap for offline mode, stylus polish, and cloud sync — but the web version is a permanent free tier.
Any modern Chromium-based browser (Chrome, Edge, Brave, Comet), plus Safari on iOS/macOS and Firefox. Chrome + Claude-in-Chrome extension is the current gold standard for AI-driven use.
Free · Any device · Any AI can drive it