What is Online Gerber Viewer?

Online Gerber Viewer is a free, browser-based Gerber file viewer for PCB designers. It runs entirely in your browser — no upload, no registration, no installation. Drag your Gerber RS-274X or Excellon drill files onto the page to view them with multi-layer overlay, measurement tools, grid overlay, and 30-language UI.

Is Online Gerber Viewer really free?

Yes, 100% free. No registration, no paid tier, no in-app purchases, no file size limits within the practical 100 MiB single-file cap. The site is supported by donations and community contributions.

Do I need to upload my Gerber files?

No. Online Gerber Viewer processes all files locally in your browser using JavaScript. Your files never leave your device. This is critical for proprietary PCB designs, unreleased products, or any sensitive project — there is no server, no cloud, no telemetry on file content.

What file formats are supported?

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 files (.drl .xln .txt .tap .npt .exc .drd), Gerber X2/X3 with attributes, and ZIP archives containing any combination of the above.

Which PCB design tools does the viewer recognize?

The smart layer identification algorithm recognizes naming conventions from 19 CAD tools: KiCad, Altium Designer, Cadence Allegro, Cadence OrCAD, Autodesk Eagle (Legacy / OSH Park / PCB-ng variants), DipTrace, gEDA PCB, Siemens PADS, Proteus PCB, Pulsonix, DesignSpark PCB, EasyEDA, CircuitMaker, CircuitStudio, Target 3001!, Zuken CR-8000 / BoardStation, Mentor Expedition PCB, and P-CAD. It uses a majority-vote algorithm to detect which CAD tool produced the file set.

Can I export my Gerber view as an image or SVG?

Yes. The viewer can export the current rendered view as a PNG with custom dimensions (width/height in pixels, aspect ratio locked). It can also export each loaded layer as a separate SVG file, bundled into a ZIP archive. SVGs use Gerber logical coordinates so they can be exactly overlaid in external tools.

Changelog

Current Version: 1.7.0
Last Updated: 2026-08-10

2026-08-10 - Version 1.7.0

New Features

Export images toolbar menu — new toolbar button with dropdown menu (PNG / SVG export), icons styled to match existing toolbar
Export PNG with custom size — dialog lets you set width or height in px; the other dimension updates proportionally; exports the current canvas content as a transparent-background PNG
Export SVG as ZIP — every loaded Gerber layer is converted to its own SVG file (named after the uploaded Gerber file + .svg) and packed into one ZIP; ZIP is named SVG_<original-zip-name>.zip, or Gerber-Images.zip when loaded as loose files; all layers are exported regardless of visibility
Coordinate-aligned SVG output — SVG export re-serializes the parsed ImageTree directly (shared path-generation logic with the canvas renderer) instead of snapshotting the canvas: each layer's viewBox maps to Gerber logical coordinates, so per-layer SVGs can be exactly overlaid and edited in external tools; output is deterministic (independent of canvas flip/zoom/visibility) and includes an <?xml?> declaration. Renderer split into renderer/index.ts (LeaferJS) + renderer/svg.ts (pure SVG serialization, no DOM dependency)

Improvements

Export menu also closes the measure/grid dropdowns when opened (and vice versa), keeping toolbar dropdowns mutually exclusive

Bug Fixes

PNG export no longer distorted — dialog's default size and aspect-ratio lock now use the visible content bounds (measured after a temporary fit-view) instead of the canvas viewport size. The Leafer export API scales X and Y independently (scaleX = w/contentW, scaleY = h/contentH), so a viewport-ratio lock caused the image to stretch; locking to the content ratio produces a distortion-free export sized exactly to the content's maximum bounds (no extra padding)
PNG export no longer has blank space on the right — the export now measures the merged world bounds of visible layers only and passes them explicitly via the screenshot option. Root cause: Leafer only excludes visible === 0 (numeric) layers from render bounds, while this app hides layers with visible = false (boolean) — those hidden layers still contributed their width to the export area, producing a wide transparent band. New getVisibleContentBounds() merges only group.visible layers, so the exported width matches the requested resolution, the height scales proportionally, and hidden layers are excluded
Export PNG dialog inputs restyled — the width/height number fields now use the same control style as the toolbar zoom scale input (border input + inline px suffix + custom up/down stepper buttons, native spinner hidden), keeping toolbar and dialog UI consistent

2026-06-29 - Version 1.6.0

New Features

Step & Repeat (SR) support in single-pass parser — Gerber RS-274X %SR…% commands now properly replicate graphics across panelized arrays. Supports both integer format (e.g. I1734292 = 17.34292mm) and EasyEDA decimal-point format (e.g. I17.34292). Handles D03 flashes, D01 path segments, and G36/G37 region mode inside SR blocks.
Excellon drill file detection fix — files starting with ;TYPE=PLATED comment header before M48 are correctly routed to the legacy parser instead of being silently dropped.

Bug Fixes

Fix single-pass parser ignoring Step & Repeat (%SR) commands — parser now correctly accumulates graphics inside SR blocks and replicates them across the specified grid

2026-06-06 - Version 1.5.0

Breaking Changes

New single-pass parser is now the default — replaces the legacy two-pass (lexer → AST → plotter) pipeline. 5x parsing faster, lower memory, identically matched output validated against all 50+ test boards. Fall back to ?parser=legacy if needed.

Bug Fixes

Fix rectangle-tool D01 paths rendering as stroked wires instead of filled polygons — finalizePath now delegates to plotRectPath for rectangle tools, matching legacy plotter behavior
Fix tool-change path flush — D handler now compares the new tool code (String(d)) against segment tool code instead of the previous tool, preventing stale segments from being flushed at the wrong time
Fix D03 standalone (D03*) not creating shapes — removed overly-strict hasX && hasY guard
Fix D03 flash not updating position — prevX/prevY now set to flash coordinates, matching legacy location-store _previousPoint update
Fix pure tool-change commands (G54D10*) entering D01/D02 draw branches through defaultGraphic
Fix region mode (G36/G37) D02 creating spurious line segments when regionSegments was empty
Fix large files (>10MB) being silently filtered — increased size limit to 100MB
Fix progress bar delay — show immediately on file load, before ZIP decompression

2026-06-06 - Version 1.4.0

Bug Fixes

Fix oblong/obround pad rendering — SVG arc sweep direction for capsule pads corrected
Fix 45°/135° diagonal capsule pad rendering — aperture macro vector line Y-offset sign inverted, connecting rectangle was zero-area
Fix canvas flip sync — origin crosshair and grid overlay X positions now mirror correctly; replace CSS scaleX(-1) with contentFlipGroup.scaleX for coherent Leafer coordinate system
Fix flip + drag pan direction — manual pan handling with negated X delta when content group is flipped
Fix ZIP import with non-Gerber files — expanded skip extension list, added 10MB file size cap
Fix large Gerber file parsing freeze — batch syntax matching by command (* / % delimiter) instead of per-token, O(n²) → O(n)

Improvements

Zoom max increased from 200× to 999.99× (20000% → 99999%)

2026-05-28 - Version 1.3.2

Bug Fixes

Fix holes in Gerber region (G36/G37) rendering — split fill paths into separate Path elements instead of merging, fix floating-point comparison for full-circle arc splitting
Fix aperture macro vector line offset direction causing round rectangle rendering artifacts (protruding corner bumps)

2026-05-24 - Version 1.3.1

New Features

"Open Example Files" button on welcome screen — loads a sample PCB project (color-easy-duino) with one click

2026-05-23 - Version 1.3.0

New Features

8 new languages: Dutch, Italian, Polish, Swedish, Romanian, Malay, Tagalog, Lithuanian
Chinese split into 3 regional variants: Simplified (简体中文), Cantonese (廣東話), Traditional (繁體中文)
Language dropdown sorted by visitor volume with vertical scrollbar
Three Chinese variants grouped together in language dropdown

2026-05-22 - Version 1.2.0

New Features

Precision measurement tools — single and continuous modes, real-time preview during drag, distance/angle/dx/dy readout in mil or mm
Status bar cursor coordinate display — real-time X/Y position in current unit
Origin crosshair lines — perpendicular guides at the Gerber origin point, track during pan/drag
Customizable grid overlay — none / lines / dots / crosshair modes, alignment to Gerber origin or bounding box
Grid auto-hides when zoomed out beyond useful spacing
Real-time cross-probe cursor with continuous coordinate tracking across all canvas layers
Unit toggle between mil and mm — measurement values and grid spacing update in real time
Canvas flip / mirror view toggle for inspecting board from different perspectives
Zoom percentage manual input with arithmetic expression support (e.g. 2*50 → 100%)
Auto-detect Gerber file units (mm / inches) on first file parse

Improvements

Layer panel refactored to flex layout: header with title/filters/All toggle is always visible, layer list scrolls independently
Language switching now performs full page reload — URL always matches the served language HTML
Simplified language initialization — URL path is the single source of truth

Bug Fixes

Fixed language mismatch when opening root URL with a stored language preference
Fixed language setting not persisting correctly across page loads

2026-05-20 - Version 1.1.1

New Features

Layer color customization with custom color picker popup at mouse position
Eyedropper tool (EyeDropper API) for picking colors from screen
Fixed header area in layer panel (title + filters + All toggle always visible)

Improvements

Switched from Pickr library to custom lightweight color picker popup
Added EyeDropper API support for screen color sampling
Right panel refactored to flex layout: header always visible, layer list scrolls independently
ZIP file name displayed in toolbar when loading from archive
All Layers eye icon enlarged for consistency

2026-05-19 - Version 1.1.0

New Features

Added 20-language internationalization with full UI translations
Added PCB logo and favicon across all pages
Added language dropdown with globe icon in toolbar

Improvements

Redesigned static pages with dark theme matching the main app
Replaced text toolbar buttons with SVG icons
Changed URL language routing from hash (#/en) to clean path (/en)
Replaced Simple.css with custom dark theme template
Fixed dropdown highlight not updating on language switch
Fixed frontmatter rendering in static pages
Optimized layout for all screen sizes

New Features

Added SEO meta tags for better search engine indexing
Added Baidu site verification
Added visitor counter
Improved about dialog with contact information
Added Chinese/English language support

Improvements

Enhanced JSON-LD structured data
Added robots.txt and sitemap.xml
Optimized rendering performance

2026-05-14 - Version 1.0.0

Initial Release

Gerber RS-274X file parsing and rendering
Excellon drill file support
Multi-layer overlay display
ZIP batch import
Drag and drop upload
Smart layer type detection
Dark theme UI
Zoom, pan, and fit controls
Responsive design

This changelog tracks major updates to Online Gerber Viewer.