ZPLKit

Open-source Swift toolkit for Zebra label printing

      ZPLKit is the engine behind The Labeler. It's a Swift package for building ZPL labels with a declarative, type-safe API, previewing them without a physical printer, sending them over the network, and verifying the result. We built it as a standalone library so anyone can use it in their own apps.
    

Four Modules

Import only the parts you need. Each module builds on the core generator:

ZPLKit — generate ZPL with Swift result builders: text, multi-line text blocks, shapes, serial numbers, and images with dithering
ZPLKitRenderer — a native renderer that parses ZPL and produces PNG previews, no external dependencies
ZPLKitPrinter — send labels over TCP, discover printers via Bonjour, and configure or query them with an async/await API
ZPLKitVerifier — confirm what actually printed using the Vision framework for barcode decoding and text OCR

Quick Start

Describe the label declaratively, then render it to a ZPL string:

import ZPLKit

let label = ZPLLabel(width: 4, height: 6, dpi: .dpi203) {
    Text("PARTS BIN A-7", at: .inches(0.25, 0.25))
        .font(.default, height: .inches(0.2))

    Barcode128("BIN-A7-001", at: .inches(0.25, 0.6))?
        .height(.inches(0.5))
        .showText(true)

    Box(at: .inches(0.2, 0.2), width: .inches(3.5), height: .inches(1.2))
        .thickness(2)
}

let zpl = label.render()

Barcodes and Graphics

Built-in support for the symbologies you actually reach for: Code 128, Code 39, QR, DataMatrix, PDF417, Aztec, EAN-13/8, UPC-A/E, Interleaved 2 of 5, and USPS Intelligent Mail. Photos and images render to monochrome bitmaps with Floyd-Steinberg or Atkinson dithering and aspect-fill cropping.

Preview Without a Printer

Render ZPL straight to a PNG so you can show a live preview in your UI:

import ZPLKitRenderer

let renderer = ZPLRenderer()
let pngData = try renderer.renderToPNG(zpl, width: 812, height: 1218)

Print Over the Network

Send to a known printer, or discover one on the local network with Bonjour:

import ZPLKitPrinter

// Send to a known printer
let printer = ZPLPrinter(host: "192.168.1.100")
try await printer.send(label.render())

// Or discover printers on the network
let browser = ZPLPrinterBrowser()
for await discovered in browser.printers {
    try await ZPLPrinter.send(zpl, to: discovered)
    break
}

You can also query status, info, memory, and full configuration, or set a printer up from scratch with type-safe presets.

Verify the Output

Rendered a label? Confirm it contains what it should, using on-device Vision:

import ZPLKitVerifier

let verifier = ZPLVerifier()
let check = try await verifier.verify(cgImage) {
    Barcode(.qr, containing: "SKU-123")
    Text("FRAGILE")
}
if !check.passed { print(check.summary) }

Installation

Add ZPLKit to your Package.swift. (The first tagged release is on the way; until then, pin to main.)

dependencies: [
    .package(url: "https://github.com/jonathanspiva/zplkit.git", branch: "main")
]

Then add the products your target needs:

.target(name: "YourTarget", dependencies: [
    "ZPLKit",           // generation
    "ZPLKitRenderer",   // previews
    "ZPLKitPrinter",    // network printing
])

Requirements

Swift 6.3+ (Swift 6 language mode, Sendable throughout)
iOS 26+, macOS 26+, tvOS 26+, watchOS 26+
No third-party dependencies
MIT licensed

The latest-OS-only floor is intentional: ZPLKit uses the newest Swift concurrency and Vision APIs rather than carrying back-compatibility shims.

Why Open Source

Zebra printers are everywhere, but working with ZPL in Swift has always been painful. We built ZPLKit for The Labeler and released it separately so other developers don't have to reinvent the wheel. It also ships 124 ZPL test fixtures you can reuse to validate any parser or renderer.

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