label-toolkit

Schema-first builders and parsers for thermal label printers. The YAML under spec/ is the source of truth. Codegen writes TypeScript packages and C tables that firmware can compile without Node.

Zebra, ZPL, and Link-OS are trademarks of Zebra Technologies Corporation. This project is not affiliated with, endorsed by, or sponsored by Zebra Technologies.

Packages

Package	What it does
@wifilabel/printer-spec	Generated command, SGD, status, and printer profiles
@wifilabel/zpl	ZPL and SGD builders, host-status parsers, scripted printer query
@wifilabel/epl2	A small EPL2 setup sequence and bitmap wrappers
@wifilabel/transport	write / read / close, plus MockTransport and readUntilQuiet
@wifilabel/webusb	WebUSB transport for Chromium browsers
@wifilabel/box-client	Stub client for a WiFiLabel box on the local network

The browser tools are served at https://wifilabel.com/tools/ from the storefront. This tree is the libraries, spec, codegen, and firmware component.

@wifilabel/zpl has no third-party runtime dependencies. Printer numbers that vary by model are marked verified: false.

import { sgd, zpl } from "@wifilabel/zpl";

zpl.setDarkness(15);
zpl.mediaDarkness(-3);
zpl.printSpeed(4);
zpl.mediaType("direct");
zpl.mediaTracking("gap");
zpl.printWidth(812);
zpl.labelLength(1218);
zpl.calibrate();
zpl.saveSettings();
zpl.factoryReset({ confirm: true });
zpl.testLabel({ widthDots: 812, heightDots: 1218, text: "HELLO" });
sgd.get("media.darkness");
sgd.set("media.darkness", 15);

The C component in c/ exposes the same builders and parsers. Builders and parsers do not allocate. Pass a caller buffer. A negative return is an error.

Develop

Node 20 or newer and pnpm 12.

pnpm i
pnpm gen
pnpm build
pnpm test

pnpm gen lints the spec and rewrites packages/spec/src/generated/, packages/spec/data/, and c/include/wlt_spec.h plus c/src/wlt_spec.c. A second pnpm gen should leave those files unchanged. pnpm test runs Vitest on the shared JSON vectors and the host C tests (ctest) against the same files.

Host C tests:

pnpm test:c

Optional Labelary preview of the golden ZPL files. This calls the public API, stays under one request per second, and caches PNGs in .cache/. It is not part of CI.

pnpm preview:labelary

Firmware

c/ is an ESP-IDF component. The example c/examples/esp-idf-basic targets esp32p4.

cd c/examples/esp-idf-basic
idf.py set-target esp32p4
idf.py build

Doc strings stay out of the binary unless CONFIG_WLT_WITH_DOCS is enabled. See docs/firmware-integration.md.

Layout

Human text under spec/ is CC BY 4.0 (LICENSE-docs). Code is MIT (LICENSE).

Prefer a ready box? wifilabel.com