HQ NextPCB's HQDFM Gerber Viewer and DfM Analysis Tool is a free online tool for displaying and reviewing PCB Gerber files and OBD++ files.
Incorporates NextPCB's Design for Manufacture algorithms and allows designers to navigate and analyze the production files and check for design issues that may impact manufacturing or cause long-term reliability issues. Based on the free desktop software HQDFM and is available to anyone, including Mac and Linux users, with no download or install and no sign-up.
HQ NextPCB