Question 1

Which barcode types does the stamper support?

Accepted Answer

Five types: CODE128 (any ASCII), EAN-13 (13 digits with checksum), UPC-A (12 digits with checksum), Code39 (alphanumeric + - . $ / + % space), and ITF (Interleaved 2 of 5, even digit count). Each line in the data textarea specifies `page,TYPE,data` (or `page|TYPE|data`).

Question 2

Do the barcodes scan with a real barcode reader?

Accepted Answer

The encoders generate spec-compliant bar/space patterns for CODE39, EAN-13, UPC-A, and ITF — including start/stop guards, checksums, and quiet zones. CODE128 uses the standard character patterns for the printable ASCII range. Most modern barcode readers should scan the CODE39/EAN/UPC/ITF output; CODE128 B works for standard ASCII text. Test on your target reader before relying on it for production.

Question 3

How do I know which barcode type to use for my data?

Accepted Answer

Use the type suggester: paste your data and the tool detects the best-fit type — 12 digits → UPC-A, 13 digits → EAN-13, only digits with even count → ITF, alphanumeric with code39 charset → Code39, otherwise CODE128. You can override the detected type per line in the textarea.

Question 4

What extra features does this tool have compared to others?

Accepted Answer

(1) Multi-line batch parser (page|type|data). (2) 5 barcode type encoders (CODE128, EAN-13, UPC-A, CODE39, ITF). (3) 6 position presets. (4) Width/height size calculator. (5) Hex color parser. (6) Checksum calculators (EAN, UPC). (7) Per-type barcode validators. (8) Bars → rectangles converter. (9) Optional text label with position calculator. (10) Text/CSV renderers. (11) Copy + Download. (12) History (localStorage, last 20). (13) Shareable URL. (14) Summary stats. (15) Data-format type suggester. (16) Multi-type batch processor with per-entry validation.

Question 5

Is my data sent anywhere?

Accepted Answer

No. All barcode encoding, PDF loading, and stamping run entirely in your browser via pdf-lib. History is stored in localStorage on this device only. Nothing is uploaded.

PDF Barcode Stamper

How to use