Tiny Online Tools
What an IPC-356 file is
An IPC-D-356A file is a bare-board electrical test netlist: a plain-text export from your PCB CAD tool (Allegro, EAGLE, Altium and others all write it) listing, for every net, the X/Y position of every point on the board a test probe can actually touch — pads, through-holes and vias. A fab or contract manufacturer uses it to build a flying-probe or bed-of-nails test fixture that checks every net for shorts and opens before the board ships.
Why single-access nets matter
A net needs at least two independent test points to be tested electrically — one to inject a signal, one to measure it. A net with only one accessible point on the whole board can't be probed that way at all, whatever the tester. This usually means a component is buried where nothing else on that net reaches the surface, or a net genuinely only touches one pad. Either way, it's worth knowing about before the board goes to test, not after a batch comes back unverified. This tool lists every such net plainly, flagged as a warning.
What else you get
Every net, sorted or searched, with its test-point and via count. A scatter plot of every accessible test point's position, so you can see at a glance whether coverage is dense or sparse across the board. And if any line in the file couldn't be classified as a known record type, the exact count and a sample of those lines — never silently dropped.
A note on scope
This reader follows the fixed-column layout used by real Allegro- and EAGLE-exported files, cross-checked against a widely used open-source IPC-356 parser. Files that deviate significantly from that layout may still parse partially; anything this reader can't classify is reported as "unparsed", not silently ignored.
Privacy
The file is read in your browser and never uploaded anywhere.