How to Verify a Signed PDF Is Authentic (Free Tool, No Account Needed)

Anyone who receives a signed PDF can check it's real. Drop it into the validator at app.firma.dev/validate-signature and get a verdict in seconds: no account, no login, no paywall.

Try It Now

The tool lives at app.firma.dev/validate-signature. Drag in any signed PDF and the validator tells you whether the signature is intact, who signed it, and when. It works on documents signed through Firma.dev, and on other PAdES-compliant signed PDFs too.

Why Signature Validation Matters

A signed PDF is only as trustworthy as your ability to check it. Certificates expire. Files get edited after the fact. A recipient who can't verify a signature is just taking someone's word for it.

Firma.dev's validator checks two signature formats:

• PAdES-BASELINE-B, the older baseline format still found on documents signed a few years back

• PAdES-BASELINE-LTA, the current standard, which embeds long-term validation data so the signature stays checkable for decades, even after the original signing certificate expires

Most people never think about which format their signing tool used. The validator handles both, so it doesn't matter which one produced the document you recieved.

How It Works

1. Drop the file. No sign-up, no upload limits tied to an account.

2. We validate server-side, using a dedicated DSS (Digital Signature Services) validation service kept separate from the infrastructure that actually signs documents.

3. Get a verdict. The result shows signature format, signer identity, signing time, and an overall validity status, in your choice of 14 languages.

Who This Is For

• Agencies sending contracts to external clients can share the verification link alongside the signed document, so the client can check it independently instead of just trusting the agency's word.

• Compliance teams get a way to confirm a signature is valid without buying or learning a third-party verification tool.

• Any recipient of a signed PDF, from either side of a deal, gets a plain answer on whether the document in front of them is the one that was actually signed.

Built for Developers Too

The validator runs on the same edge function developers can call directly. validate-signature takes a base64-encoded PDF and returns structured validation results your own app can act on. An embeddable version of the tool is also available as a Framer code component, so it isn't locked to a specific page on our site.

Full request and response details are being added to docs.firma.dev as the API surface finalizes. If you're integrating validation into your own product now, reach out and we'll get you the current shape.

FAQ

Get Started

Firma.dev is built so anyone can check a signature without asking us to. Try the validator now, or get started with Firma.dev for free, no credit card required if you're ready to send your own documents for signature.