Inspect any PCB fab bundle in the browser.
Drop a ZIP or TAR of Gerbers, an ODB++ .tgz, or an IPC-2581 .xml. Layer toggles, snap-to-pad measurement, 3D mode, diff — every feature, free.
- .zip
- .tar
- .tgz
- .gbr
- .drl
- .xml
About Gerber Viewer
Loft Gerber Viewer opens Gerber RS-274X and X2, Excellon drill files, ODB++ jobs and IPC-2581 XML in your browser, with nothing to install. Drop the fab .zip or .tgz from KiCad, Altium Designer, EAGLE or any PCB CAD tool. It detects layer roles, measures in millimetres with snap-to-pad at the file's own resolution, highlights every flash of a D-code aperture, and runs DRC against fab-house presets. Flex and rigid-flex boards are recognised from an ODB++ layer matrix or a Gerber job file. The view is shareable as a URL.
What it does
- RS-274X parser with full Gerber X2 attribute support
- Excellon and XNC drill files auto-detected
- ODB++ (.tgz) and IPC-2581 (.xml) open on the same canvas as Gerber, with layer names, measurement and DRC
- .zip / .tar / .tar.gz / .tgz archive auto-extract
- Loose .gbr / .drl / .gtl / .gbl / .gts / .gbs / .gko / .gm1 files accepted
- Per-layer toggle, reorder, color, and opacity controls
- Snap-to-pad measurement at the file's native coordinate resolution (typically 0.1 µm)
- Trace-width probe shows the conductor width under the cursor — click any trace in inspect mode to pin a persistent dimension annotation
More features
- Aperture highlight — click any D-code row in the aperture table to glow every flash of that tool on the selected layer
- DRC checks with preset rule packs (fab-standard, hobbyist, JLCPCB / PCBWay) and per-rule overrides; violations group into an error explorer that recenters the viewport on click
- X2 netlist surfaced from %TO.N attributes — click a net to highlight every connected pad and stroke across copper layers
- WebGL renderer with stencil-based polarity for clean overlapping fills
- Viewport, layer visibility, color, and opacity encode into the URL fragment for sharing
- PNG, SVG, and DXF export
- Soldermask, silkscreen, copper, paste, drill, and outline layers rendered with realistic colors
- Bottom-side default-hidden until toggled (avoids overlap clutter on first load)
- Flex / rigid-flex board detection with stackup pane (auto bend-radius math per IPC-2223)
- Aperture macro support including primitive 7 (thermal) edge cases
- Pick-and-place CSV overlay (KiCad .pos, JLCPCB CPL, Altium PnP auto-detected)
- Drag-and-drop or file-picker input
- Works offline after the first visit (PWA cache)
How to use Gerber Viewer
Drop your fab archive
Drag a .zip / .tar / .tar.gz of your fab output, or loose .gbr / .drl files. The viewer detects which layer is which automatically.
Toggle layers
Click any layer in the side panel to show or hide. Reorder for diff inspection. Adjust per-layer color and opacity.
Measure
Switch to measure mode. Click two points — distance snaps to pad centers and trace centerlines. Trace-width probe shows the conductor width under the cursor.
Share or export
Copy the URL — viewport and visible layers are encoded in the fragment. Or export PNG / SVG / DXF.
Frequently asked questions
How do I open a PCB file online?
Drop the manufacturing files your design tool exported: a .zip of Gerber and drill files from KiCad, Altium, EAGLE or EasyEDA, or an ODB++ or IPC-2581 package. The board appears layer by layer, top and bottom, and you can measure it. Native design files such as .kicad_pcb or .PcbDoc need their own program; export Gerbers from them first.
What Gerber formats does this support?
RS-274X (extended Gerber) and Gerber X2 attributes. Excellon and XNC drill files are auto-detected. Older RS-274D (no embedded apertures) is not supported.
What archive formats can I drop?
.zip, .tar, .tar.gz, and .tgz. Loose .gbr / .drl / .gtl / .gbl files are also accepted.
Can it open ODB++ or IPC-2581?
Yes, both. Drop an IPC-2581 .xml or an ODB++ .tgz and you get copper, drill, soldermask, silkscreen and the board outline on the same canvas as Gerber, with layer names, measurements and DRC read straight from the file. IPC-2581 also carries its net names into the netlist panel. ODB++ nets live outside the feature records and are not read yet.
Does it handle flex and rigid-flex boards?
Yes, from ODB++ and from a Gerber job file. An ODB++ job is read for coverlay, stiffener and the bend, flex and rigid regions, which are drawn as a tinted overlay so you can see which part of the board bends. The board reports itself as flex or rigid-flex from its own layer table. Pad shapes the job defines for itself are read too, so nothing is silently dropped. Material thicknesses are not read: ODB++ has no standard place for them, so the stackup table and bend-radius figure still need a Gerber job file.
How accurate are the measurements?
Every file is read at its own coordinate resolution and converted to millimetres once, so an inch board and a millimetre board measure the same. The mm / in toggle changes what you read, never what is measured — dimensions, measurements and DRC verdicts are identical either way. Pad-center snap is geometric (centroid of the aperture flash).
Is Gerber a trademark?
Yes — Gerber is a registered trademark of Ucamco NV. Loft Tools is an independent third-party viewer and is not affiliated with or endorsed by Ucamco.