条码印章

Why stamp a code on a PDF

A barcode on a document turns paper into a lookup key. Warehouse pick sheets, contract packets, equipment tags, intake forms — anywhere a person with a scanner or phone needs to jump from a printed page to a record, a stamped code does the job. This tool generates the code in your browser and draws it onto the PDF as a high-resolution PNG, so it stays sharp at small sizes and scans reliably off a laser printer.

Two symbologies cover the common cases. QR codes hold URLs and longer strings and scan from any phone camera. Code 128 is the linear barcode logistics and asset systems have used for decades — compact, fast to scan, and readable by every handheld gun scanner ever made.

Three ways to fill the code

Fixed text stamps the same value on every selected page — a tracking URL, a document ID, a return address encoded for a mail scanner. File name encodes each file's name, so a batch of invoices comes out with each PDF carrying its own identifier. The counter source numbers stamped pages sequentially with a prefix, start number, and zero-padded digit count — ASSET-0001, ASSET-0002, and so on — which is what asset tagging and sequential work orders actually need.

Unlike tools that stamp one value across the whole document, the counter gives every page a distinct code, and the file-name source gives every file in a batch its own.

Placement and page control

The stamp lands where you put it, on the pages you choose.

Private by construction

The barcode is generated by an encoder running entirely in your browser, and the PDF is stamped locally with pdf-lib. Nothing — not the document, not the encoded value — leaves your device. That matters when the code points at an internal asset system or the document is a contract you would not email to a stranger.