The helper program

TagAlly Pro is two parts: the panel inside InDesign, and a small helper program that runs on your own computer. The helper does the work InDesign cannot do itself — repairing the exported PDF and validating it against PDF/UA-1. This page is where you get it.

If you already have the plugin, you do not need this page. The panel brings the same helper with it and sets it up at one click: it unpacks it into your application support folder and starts it. Nothing is written to disk unless you ask for it. This page describes the manual way, for the other cases: a second computer, a colleague, or a machine where installing plugins is restricted.

Everything stays on your machine. The helper listens only on the local loopback interface, so nothing on your network can reach it, and no document is ever sent anywhere.

Using the free TagAlly Check? Then this page is not for you either. TagAlly Check never exports and never validates, so it needs no helper program, no Java and no veraPDF. It is installed from the Adobe Marketplace and works immediately. More about TagAlly Check

What you need first

Three things have to be present before the helper can do its job. All three are free.

Node.js, version 18 or newer: Runs the helper itself. The installer from nodejs.org is enough; no configuration is needed.
A Java runtime: Used by the PDF repair step. Any current Java installation works. On macOS you may already have one.
veraPDF: The free open-source validator that performs the actual PDF/UA check. It is not included: install it once, as described below, and the helper finds it by itself.

Installing veraPDF

veraPDF is the free, open-source validator that does the actual PDF/UA-1 check. TagAlly Pro does not bring it along, but it can fetch it for you: if veraPDF is missing, the panel offers to install it right after the helper starts, or later via Install veraPDF on the second tab. About 33 MB from verapdf.org into your user folder, no administrator rights. The ways below are for doing it yourself, for example on a machine that must not go online. veraPDF needs a Java runtime, which the helper needs anyway.

macOS, the short way: if you use Homebrew, one command in the Terminal does everything.

brew install verapdf

macOS and Windows, the installer:

Go to verapdf.org/software and download the veraPDF Installer. It is a ZIP archive.
Unpack it and start verapdf-install (on Windows verapdf-install.bat). If nothing happens, Java is missing: install it first, for example Temurin from adoptium.net, then try again.
The installer asks where to put veraPDF. Keep the suggested folder, verapdf in your user folder, because that is the first place the helper looks. Leave the other options as they are.

Check that it worked: in the panel, open the second tab and press Engine reachable?. The answer should name the veraPDF path. If the helper was already running, start it again once.

Where the helper looks: verapdf in your user folder, /Applications/veraPDF, /usr/local/bin and /opt/homebrew/bin on macOS; Program Files\veraPDF and the local application data folder on Windows; and anything on the system path. Installed somewhere else? Open config.json in the helper folder and enter the full path under verapdfPath.

Download

Download the helper, version 1.2.7

ZIP archive, about 12 MB, for macOS and Windows alike. It contains no installer and changes nothing on your system: you unpack it wherever you like and start it from there.

If you want to be sure the file reached you unchanged, compare its SHA-256 checksum against the one we publish in the accompanying file. On macOS the command is shasum -a 256, on Windows certutil -hashfile with SHA256.

Unpack and start

Unpack the archive. A folder named tagally-engine appears. Put it on your built-in drive, wherever you keep your tools. Avoid three places: folders that are emptied automatically, such as Downloads on some systems; network drives, which are not always mounted; and cloud folders that store files on demand (iCloud Drive with Optimise Storage, Dropbox Smart Sync). Those replace rarely used files with placeholders, and the helper then loses the Java library it needs.
Start it by double-clicking START TagAlly (macOS).command or START TagAlly (Windows).bat. Apart from those two and config.json, the folder holds only a programm subfolder you never need to open.
A terminal window opens and stays open. That window is the helper: leave it running while you work, and close it when you are done.
In InDesign, open the TagAlly Pro panel and press Engine reachable? under Check & post-process. It should answer with the version number.

On macOS the first start is refused with a warning that Apple could not verify the file. That is normal for a program not distributed through the App Store, and it says nothing about the file itself.

Do not press the blue button in that dialog: it moves the file to the trash. Press Done instead, then open System Settings → Privacy & Security, scroll to the bottom, and choose Open Anyway next to the message about the file. You confirm this once, never again. From macOS 15 this is the only way; the older right-click trick no longer works.

Once it is unpacked you may delete the archive. Do not delete the unpacked folder: it is the program itself, and it is needed every time you start the helper.

Updating

If you have the plugin, press Set up again under ⚙ Advanced after a plugin update. It stops the running helper, unpacks the new version over the old one and starts it. Manually, it works as follows.

Unpack the new version over the old folder and start it again. The starter notices that an older helper is still running, shuts it down and takes over. You do not have to close anything by hand.

If it does not start

The window says Node.js was not found: Node is missing or not on the system path. Install it from nodejs.org and start the helper again.
The window says port 8474 is already in use: Another program occupies the port the helper needs. Close it, or tell us which program it is and we will look for a way around.
The panel says veraPDF was not found: Usually veraPDF is simply not installed yet. It is free and takes a minute: installing veraPDF. If it sits in an unusual place, open config.json in the helper folder and enter the full path to the veraPDF program under verapdfPath.

Still stuck? The troubleshooting section of the FAQ covers the common cases in more detail, and you can always write to us.