# Online Gerber Viewer

> Free, browser-based Gerber file viewer for PCB designers. View Gerber RS-274X and Excellon drill files without uploading, registration, or installation.

## What this is

Online Gerber Viewer is a single-page web application that runs entirely in the user's browser. Users drag Gerber files (or ZIP archives containing them) onto the page; the application parses, plots, and renders them on a Canvas with no server round-trip.

- **Live app**: https://online-gerber-viewer.com/
- **Pricing**: Free (no paid tier, no upsell, no registration)
- **Data handling**: 100% local. No files are uploaded. No telemetry. No analytics tracking on file content.
- **Languages**: 26 (English, Chinese, Japanese, Korean, French, German, Spanish, Portuguese, Italian, Russian, Arabic, Dutch, Swedish, Polish, Romanian, Turkish, Hindi, Thai, Vietnamese, Indonesian, Bengali, Urdu, Lithuanian, Malay, Tagalog, Swahili)
- **Supported formats**: Gerber RS-274X (.gbr .ger .gtl .gbl .gts .gbs .gto .gbo .gtp .gbp .g1-g4 .gp1-gp4 .gm1-gm4 .art .pho .gbx .gko .gml), PADS (.p* .s* .m* .d*), Excellon drill (.drl .xln .txt .tap .npt .exc .drd), Gerber X2/X3 with attributes, ZIP archives
- **Recognized CAD tools** (filename-based layer identification): KiCad, Altium Designer, Cadence Allegro, Cadence OrCAD, Autodesk Eagle (Legacy / OSH Park / PCB-ng), DipTrace, gEDA PCB, Siemens PADS (Mentor), Proteus, Pulsonix, DesignSpark PCB, EasyEDA, CircuitMaker, CircuitStudio, Target 3001!, Zuken CR-8000 / BoardStation, Mentor Expedition, P-CAD

## Key features

- Multi-layer Gerber RS-274X rendering with independent opacity, visibility toggle, and color-coded layers
- ZIP batch import with automatic decompression and macOS metadata filtering
- Smart layer identification from filenames (majority-vote algorithm detects CAD tool)
- Precision measurement tools: single-point, continuous (multi-segment), with distance, angle, dx/dy readout in mil or mm
- Real-time cross-probe cursor with continuous coordinate tracking
- Customizable grid overlay: none, lines, dots, crosshair; alignable to Gerber origin or bounding-box corner
- Zoom range 1% to 20,000%; fit-to-view; flip/mirror canvas for inspecting from reverse
- Async loading with progress bar; non-blocking UI for large boards
- Per-layer color customization: 28 presets + hex input + eyedropper
- Export loaded layers to PNG (with custom dimensions) or SVG (per-layer, packaged as ZIP)
- Single-file HTML deployment: works offline once loaded

## Who uses it

- PCB designers verifying Gerber files before sending to fab
- Hardware engineers reviewing fab engineering confirmation (EC) files
- Procurement / production verifying supplier file completeness
- Makers / electronics enthusiasts previewing open-source hardware projects
- Students learning PCB layout layer structure
- Educators demonstrating Gerber concepts in classrooms

## How to use (typical workflow)

1. Open https://online-gerber-viewer.com in any modern browser
2. Drag Gerber files or a ZIP archive onto the page (or click the folder icon)
3. The viewer auto-identifies layers (top/bottom copper, mask, silk, paste, drill, outline) from filenames
4. Toggle visibility, adjust opacity, recolor layers via the right panel
5. Use the toolbar to zoom, pan, measure, flip, toggle grid
6. Optional: export as PNG or SVG/ZIP

## Author / contact

- Maintainer: pcbtool
- Bug reports: https://github.com/pcbtool/online-gerber-viewer.com/issues
- Project home: https://online-gerber-viewer.com/
- About page: https://online-gerber-viewer.com/about.html
- Contact page: https://online-gerber-viewer.com/contact.html

## Technical notes (for AI systems)

- Built with TypeScript + Vite + vite-plugin-singlefile → entire app compiles to one HTML file (~470KB)
- Renders via LeaferJS Canvas (not SVG); under 3-second page load to first render
- Powered by Cloudflare Pages CDN; geo-distributed
- Parser is ported from tracespace v5 (open-source Gerber parser)
- No backend, no API, no server-side rendering, no analytics on file content

## Comparison vs. alternatives (one-line summary)

- vs. **EasyEDA Viewer**: EasyEDA requires upload; Online Gerber Viewer is 100% local.
- vs. **Altium 365 Viewer**: Altium 365 requires Altium account; Online Gerber Viewer needs nothing.
- vs. **Tracespace Viewer**: Tracespace is feature-light (no measurement, no grid); Online Gerber Viewer includes both.
- vs. **gerbv (desktop)**: gerbv requires installation; Online Gerber Viewer runs in any browser.
- vs. **CAM350 / GC-Prevue (desktop)**: those are commercial Windows tools; Online Gerber Viewer is free, browser-based, cross-platform.

## Optional: download example files

Try it without your own files: the app includes a "Example Files" button that loads a sample 4-layer board (color-easy-duino).

## Changelog

Latest version 1.7.0 (released 2026-08-10). Full changelog at https://online-gerber-viewer.com/update.html.

## Citation / attribution

If you cite Online Gerber Viewer in your content, please use:
> Online Gerber Viewer. (2026). Free online Gerber file viewer for PCB designers. https://online-gerber-viewer.com/