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fabPlane Tools · KiCad in the browser

PCB Fiddle

Paste a GitHub, Codeberg or GitLab repo and PCB Fiddle opens its board and schematic in a real PCB editor, in the browser, at a link you can share. It's KiCad's own engine compiled to WebAssembly, with the fabPcb interface on top. You don't need an install or an account.

Open pcbfiddle.com
Live at
pcbfiddle.com
Opens
Public GitHub, Codeberg and GitLab repos; local KiCad files
Formats
KiCad .kicad_pro / .kicad_pcb / .kicad_sch, Eagle .brd (XML), EasyEDA Pro .epro2
Engine
KiCad compiled to WebAssembly, in a Worker thread
Interface
fabPcb, the fabPlane PCB editor UI
Mode
Read-only for now
PCB Fiddle showing the Koyomi LVDS hat PCB: project tree on the left, the board canvas in the middle, and item counts in the properties panel
pcbfiddle.com/gh/TensorFleet/koyomi-lvds-hat: the project tree, the board on the canvas, and per-type item counts (608 tracks, 112 vias, 35 footprints).
PCB Fiddle with the Layers panel open and a DRC report listing clearance violations
The Layers panel and a DRC run. Each violation shows its board coordinates.
PCB Fiddle showing the Koyomi LVDS hat schematic with the hierarchy panel and ERC tab
The schematic opens in its own tab, with the sheet hierarchy and ERC.

What it does

Anyone with a link can open a public hardware project in PCB Fiddle. It does for KiCad boards what a code playground does for snippets. A repo becomes a short, stable URL: 

pcbfiddle.com/gh/TensorFleet/koyomi-lvds-hat
pcbfiddle.com/gh/owner/repo/@main/boards/hat.kicad_pcb
pcbfiddle.com/cb/NollKollTroll/OpenSpand
pcbfiddle.com/gl/sixxie/dragon64

/gh/, /cb/ and /gl/ mean GitHub, Codeberg and GitLab. After the repo name you can add @ and a branch, tag or commit, then a path to one board file. The page shows the project tree, the PCB and the schematic in separate tabs, and panels for layers, nets and item properties. You can also run DRC on the board or ERC on the schematic.

Formats

SourceHow it opens
KiCad.kicad_pro, .kicad_pcb and .kicad_sch open natively.
Eagle XML .brd files are converted to .kicad_pcb in the browser before the viewer starts. A banner lets you download the converted KiCad files.
EasyEDA Pro .epro2 projects are converted the same way. If the git tree has no board, PCB Fiddle checks the latest GitHub Release, where EasyEDA Pro projects usually live.
Local filesDrop files on the home page. They stay in your tab and are never uploaded.

How it works

The editor is KiCad. The viewer is the fabPcb interface running on KiCad's engine compiled to WebAssembly. That is about a 34 MiB module, and it runs in a Web Worker so the page stays responsive. The home page doesn't load it. It is fetched from images.fabplane.com only when you open a board.

Each repo is cloned once. The first time a repo is opened, a Cloudflare Worker clones it and stores a snapshot in R2, keyed by commit SHA. It's the same bucket that holds fabplane.com's open-source catalog, so the two sites don't keep two copies of a repo. Later visits read that snapshot. Every night the Worker rechecks repos that were viewed in the last seven days and clones them again only if the branch has moved. Links pinned to a commit never change.

Links unfurl as 3D boards. When you paste a PCB Fiddle link into Slack, X, Discord or a GitHub issue, the preview card is a 3D render of the board. PCB to 3D draws it and stores it next to the snapshot, so each commit is rendered only once, whichever site asks first.

Static first. Pages and viewer slugs are served as static assets from Cloudflare's CDN. The Worker runs only for the clone-on-miss API, preview images and the nightly refresh.

How to use it

  1. Go to pcbfiddle.com. Paste a repo URL such as github.com/owner/repo, or pick one of the catalog boards.
  2. To open a repo straight away, change the URL: replace github.com with pcbfiddle.com/gh.
  3. For files on your computer, drop .kicad_pro, .kicad_pcb, .kicad_sch, .brd or .epro2 files on the home page.
  4. Use the tabs to switch between the PCB and the schematic. The Layers and Nets panels, DRC and ERC work on the loaded design.
  5. To share the board, copy the URL. Add @<commit> if the link should keep showing that exact revision.

PCB Fiddle is read-only for now: it opens and inspects designs, but doesn't save edits back to the repo. Editing through the same KiCad engine is planned for a later release.