Every Chinese company's business licence carries an 18-character registration code (USCI). The code has internal structure and a GB 32100-2015 check character, so a code copied from a licence photo can be verified offline - no registry access needed. Free in-browser checker plus an open-source MIT library (zero dependencies), tested against 2,149 real codes from official disclosure files. Honest limit built in: a passing check proves correct transcription, not that the company exists.
