Before you start

What you need

On your desk

A Mac (current macOS)
Your existing ups.com account — nothing changes there

A ZPL thermal label printer (Zebra or compatible)
Your sitelead download — UPS Label Printer (full app) or Mac Bridge (lean, one Mac)

No API keys here. Unlike a marketplace tool, this needs no keys or logins of ours — everything happens on your Mac, and no address or shipment detail ever leaves it. If you sell on Temu instead, the API-key guide is over here.

Install the app

Unzip your download and drag the app (or the whole Mac Bridge folder) into Applications. Open it the first time with right-click › Open › Open — that's how macOS lets you approve software from outside the App Store, and it's only needed once.

Mac Bridge only: if macOS offers to install the command line developer tools, click Install — it's a one-time free download from Apple that provides Python, which Mac Bridge runs on. Then open Mac Bridge again.

Choose your printer

Run the printer setup (Mac Bridge: Setup — choose your printer.command) and pick your thermal label printer's queue name from the list it shows. This tells the app where to send labels.

Tell ups.com you have a thermal printer — once

On ups.com go to Profile › Ship Settings › Printer preferences and set label printing to Thermal printer. This makes ups.com hand over a thermal (ZPL) label instead of a PDF, which is what prints correctly.

Create a label — it just prints

Create your shipment on ups.com exactly as you do now — same account, same flow, nothing new to learn. The label goes straight to your thermal printer at proper label size, rendered locally on your Mac. No pop-ups, no PDF resizing, no second attempts.

Start it automatically at login (recommended)

Open System Settings › General › Login Items, click + and add the app. It then runs quietly every time you log in — set it and forget it.

If something doesn't print

The usual fixes

Label came out as a PDF / wrong size

ups.com is still set to laser/PDF. Re-check step 3 — Profile › Ship Settings › Printer preferences must be set to Thermal printer.

macOS blocked the first launch

Use right-click › Open › Open rather than a double-click the very first time — that's how macOS approves apps from outside the App Store.

Printer isn't in the list

Add it in System Settings › Printers & Scanners first, then run the printer setup again so its queue name appears.

Mac Bridge: watch it work

Open Start Mac Bridge (with log window).command to see every request in a Terminal window. Captured labels and a full bridge.log are saved under ~/Library/Application Support/Mac Bridge/.

Still not printing? Email ln3@sitelead.co.uk with your printer model, your macOS version and (for Mac Bridge) the bridge.log file — we run this on our own shipping desk and we'll get yours printing.

FAQ

UPS-on-Mac questions

Do I need UPS API keys or a developer account?

No. This isn't an API integration — you keep creating labels on ups.com with your normal account. The app only handles printing, on your Mac. Nothing of yours passes through us.

Which printers work?

ZPL thermal label printers — Zebra and compatible models — the ones ups.com fights hardest against on a Mac. Tell us your model before you buy if you're unsure and we'll confirm.

What's the difference between UPS Label Printer and Mac Bridge?

Same result. UPS Label Printer (£99 + VAT) is the full app licensed to your business, for use on your Macs. Mac Bridge (£30 + VAT) is a lean background helper licensed to one Mac. This guide covers both.

Does my shipment data go anywhere?

No. Labels are rendered and printed locally on your Mac — addresses and shipment details never leave it. There are no servers of ours involved.

Printing ups.com labels on a Mac