Tools for your documents

Compare files and texts, add watermarks and create verification links.

Register a document

Create a verification link and add a QR code to your PDF.

Register website text

Keep versions of your website text, share their history and detect changes.

Protect spreadsheet data

Replace sensitive values with consistent identifiers and restore them later.

Compare two files

Check whether two files are identical, even with different names.

Watermark a PDF

Add text to your PDF pages. Set its position and transparency.

Calculate SHA-256

Get a file fingerprint and compare it with a reference.

Watermark images

Add a name, recipient or visible usage notice to a PNG or JPEG image.

PDF copies for recipients

Create a marked copy for each recipient and download its final fingerprint.

Protect PDFs from AI

Set AI usage restrictions, add an optional opening password and create identifiable copies for recipients.

Check a folder

Save your files’ fingerprints and check which files have changed or are missing.

Compare two texts

Find added and removed lines between two versions of a text.

Received a document with a code or QR?Check whether your copy matches its registered version.

Check a document

Same name. Not necessarily the same document.

You send a quote, then receive a copy with a changed amount. Both files have the same name. Your registration link lets you check whether the copy matches the file you sent.

How to register and share a document

Create a reference version that recipients can check.

  1. 01

    Select your document

    Choose the version you want recipients to check: a quote, report or other file.

  2. 02

    Get a verifiable document

    For a PDF, add a visual stamp with a QR code and download the registered copy. You can also register a file without modifying it.

  3. 03

    Share your document

    Send the stamped PDF or the verification link. Recipients can check whether their copy matches.

Register my first document

Everyday documents

For the files you already share.

Send them as usual. Add a way to check the exact copy.

Quotes and proposals

Register the quote before sending it. If you receive another copy later, the link lets you check whether it matches the registered file, even if the name is unchanged.

Register a document

Plans for document registration

Register files by hand. Share a verification link. Public checks are free.

Free

€0 / month

1,000 registrations / month

  • PDF stamp with verification QR
  • Version history and signed receipts
  • Shareable verification link
  • Usage warnings before reaching your limit
Create account

Pro

€29 / month

25,000 registrations / month

  • PDF stamp with verification QR
  • Version history and signed receipts
  • Shareable verification link
  • Usage warnings before reaching your limit
Choose plan

Scale

€149 / month

250,000 registrations / month

  • PDF stamp with verification QR
  • Version history and signed receipts
  • Shareable verification link
  • Usage warnings before reaching your limit
Choose plan

Need it inside your software?

Enterprise integrations are scoped with you: workflow, volume and technical handover. Tell us what you need to automate.

Discuss an integration →

One new version uses one registration. No automatic upgrades or excess charges. Allowances reset monthly at 00:00 UTC on day 1. Prices exclude applicable taxes. Local tools in this library are free and do not use registrations. Other account functions have separate allowances, detailed in your account.

Enterprise

Your software. Our verification.

If your business issues or receives documents regularly, manual registration is not the answer. We help you integrate verification into your existing workflow, case by case.

Discuss an integration

For document systems, reports, quotes, client portals and other business software. We assess compatibility; these are not ready-made connectors.

  1. 01

    Tell us how you work

    Which software you use, which documents you handle and what you need to automate.

  2. 02

    We assess your integration

    We propose a workflow and provide documentation and examples for your system.

  3. 03

    Test before rollout

    Validate the process with your technical team before enabling it for your users.

What document verification checks

File integrity, record signature and version status.

Does this copy match?
We compare its fingerprint with the registered file. A changed amount, clause or metadata makes the file different. We do not point out which part changed.
Data stored
Registration and comparison calculate the fingerprint in the browser. The file contents are not sent to CheckThisFile. Keep the original: the record cannot reconstruct it.
A signed record
CheckThisFile signs the record. You can download its evidence and check the signature offline with our verification guide. Current status must be checked online.
Version control
Keep a history of registered versions and check whether a version is current, replaced or withdrawn.

Frequently asked questions

The essentials before you start.

What does registering a document mean?

We keep its digital fingerprint and the date we receive the record. You get a link so someone else can compare their copy. For a PDF, you can download a copy with a visual stamp and QR code. We do not review the content or certify authorship or truth.

What information does the record verify?

It checks whether a copy exactly matches its registered version and lets you consult the record’s signature and status. A match does not establish who wrote the document, whether its contents are true or its legal validity. The date is when CheckThisFile received the record, not an independent timestamp. The record does not establish email delivery or reading.

What does the PDF stamp include?

A comparison sheet with a code and QR, appended to your PDF. It is included in registration and prepared in your browser. We register the finished PDF's fingerprint: share that downloaded copy, not the previous file. This is not a qualified electronic signature and does not replace signatures on an already-signed PDF.

Do you need to store my file?

Not for this registration. The fingerprint is calculated in your browser. We receive the fingerprint and the details needed for the record, not the document contents.

What if I edit the file?

The edited copy will no longer match the previous record. Even metadata changes can alter the fingerprint while the document looks the same. Create a new record for the changed file.

How does the recipient check it?

They open your shared link, or scan the stamped PDF's QR code, and select their copy. Comparison happens in their browser, with no account or file upload. A record link or code is required: we do not search documents by their content.

Do you monitor the document after registration?

No. CheckThisFile does not monitor your files. Changes are detected when someone compares a copy against the record.

Can my company integrate this into its software?

Yes. Tell us which software you use and how you issue or receive documents. We assess the case and provide a tailored proposal and documentation. No API setup is needed to use the tool manually.

Register a document and share its verification link

Recipients can compare their copy with the version you registered.

Create account