Swap the names. Keep the document.

TGDC Swap is an iOS app that rewrites the personal data in a document instead of blacking it out. A name becomes another name, an account number another number of the same shape. The letter still reads like a letter, and nobody in it exists.

In App Store review

Where it runs

On the device. No document is sent anywhere to be processed.

Account

Not needed. Scanning, swapping and sharing work while signed out.

Documents

PDFs, camera scans and photos, in German and English

Before and after

Before is what the app reads. After is what it writes, at the same position and in the same size.

Why a black bar is the wrong tool

A blacked-out document tells everyone that something was there, and it stops being a document: the sentence breaks, the table loses a column, the form no longer looks like the form it is.

A swapped document keeps its shape. The salutation still greets someone and the invoice still adds up to a plausible total, so everything that made the paper useful survives.

What the app looks for

Two mechanisms run over every page, because the values on a page are of two different kinds.

• Structured identifiers have a shape, so rules find them: email addresses, phone and fax numbers, IBANs and BICs, tax and VAT numbers, commercial register entries, licence plates, customer and reference numbers.
• Names of people, organisations and places have no shape of their own, so they are found by what stands around them (a salutation, a field label, a legal form such as GmbH or AG) together with the language analysis Apple builds into iOS. Both halves run on the device. Nothing is trained by us, and nothing is fetched to make them work.

The rule layer is ported from the anonymisation engine we already run over real corporate document estates, with the false-positive defences it carries there: without them, a phone-number pattern swallows postcodes and dates.

One person, one stand-in, every time

A document rarely names you once and consistently. It says Anna Weber in the address block, A. Weber in the reference line, Frau Weber in the salutation and anna.weber@example.de in the footer. A tool that treats those as four people produces an unreadable result.

TGDC Swap resolves them into one identity, gives that identity one stand-in, and writes it back in the form each position needs. The mapping stays on the device, so a second document about the same person next month gets the same stand-in and the two files still belong together.

When the app is not sure, it says so

The failure that matters is a value nobody detected: nothing flags it and the file goes out looking finished.

So the app reads its own output back. It looks for anything shaped like a person, a company or an address that it cannot account for, and if something is left it holds the document and shows you the spot. You are standing right there, and you can tap what was missed.

Scope

PDFs with real text, scanned PDFs, camera scans and photos. Detection covers German and English. Office formats are not handled: a document rewriter for OOXML is a separate class of problem.

Sharing a document is separate, and optional

You can hand a swapped document to The General Data Company for our licensed corpora. It is a distinct action behind an explicit consent screen that shows exactly what is transmitted, and only the swapped version is transmitted. The original file and the name mapping cannot travel that path at all, because the upload accepts a type that contains neither. Nothing about the tool depends on it.

Last updated · August 2026