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Local-first fabrication preflight

Gerber & PCB Manufacturing Tools

Check the exact PCB fabrication ZIP before you send a job to a board house. The local preflight tool inspects Gerber and drill files as one project, then reports missing layers, mixed units, duplicate roles and outline-envelope problems. No design data is uploaded to EasyTool.me.

RUNS LOCALLY

Gerber ZIP Preflight Checker

Drop the final fabrication ZIP. Check package completeness, drill data, unit consistency, duplicate layer roles and artwork outside the outline, then export HTML or JSON.

Preflight a Gerber ZIP → GUIDE + EXTERNAL TOOL

Solder Paste Stencil Guide

Identify the paste and outline layers used for a printable stencil workflow, then continue to the clearly labeled third-party generator.

Read the stencil workflow →

A practical PCB fabrication package

A Gerber file describes one plotted image, not an entire PCB project. A typical two-layer order therefore includes separate top and bottom copper, solder-mask and silkscreen images, a board outline, and drill data. Assembly orders can also require paste layers, component placement data and a bill of materials.

Filename extensions such as .gtl and .gbs are conventions rather than a complete guarantee. Gerber X2 can include attributes such as FileFunction that identify a file's purpose inside the file. The inspector shows that attribute when present and falls back to the filename when it is absent.

Common files and what they mean

Typical filePurposePreflight question
.gtl / .gblTop / bottom copperAre both copper sides present and using the same origin?
.gts / .gbsSolder mask openingsAre pad openings and mask clearances visible in CAM?
.gto / .gboSilkscreenDoes text avoid exposed pads and board edges?
.gtp / .gbpSolder pasteIs the correct side selected for the stencil?
.gko / .gm1Outline / mechanicalIs there one closed outline with intentional slots?
.drlDrill coordinatesAre units, origin, plated and non-plated holes correct?

A report-first release workflow

Visual inspection and structural checks answer different questions. Start with the package report to catch missing or inconsistent files, then use a CAM viewer to inspect the actual artwork. Keeping the downloaded HTML report with the released ZIP also creates a lightweight record of what was checked.

Recommended preflight order

  1. Run electrical and design-rule checks in the PCB editor before exporting.
  2. Export the intended copper, mask, silkscreen, outline and drill outputs into a clean folder.
  3. Run the final ZIP through the local checker to catch missing core files, mixed units, duplicate roles, unknown formats and suspicious coordinate envelopes.
  4. Open the exact final manufacturing archive in a real CAM viewer. Metadata inspection cannot prove that artwork, clearances or polarity are visually correct.
  5. Compare the board-house preview and order parameters with the design: layer count, thickness, copper weight, finish, color and controlled-impedance requirements.

Why the inspector does not claim to be a CAM validator

The browser tool performs a fast structural pass. It does not fully implement every Gerber aperture macro, polarity operation, step-and-repeat rule or Excellon dialect, and it does not render manufacturing artwork. The reported width and height are coordinate extents, not a guaranteed finished board dimension. A successful report means the file looks structured enough for the next review step; it is not manufacturing approval.

Primary references

Last reviewed: July 31, 2026. If a reference or parser result is wrong, send the page URL and a minimal non-confidential sample through the contact page.