OpenSig
OpenSig gives creators, entrepreneurs and teams a simple way to sign and timestamp files of any kind — no account, no uploads, no complex workflows.
Protect your intellectual property. Sign contracts. Share verifiable proof that lives forever.
Think of OpenSig as your digital pen. Just open the app and sign in seconds. You retain your files, your workflow, and gain undeniable proof whenever it counts.
Your work is your livelihood. Publishing media and sending documents without proof of authorship puts your creations at risk.
OpenSig is simple and fast, so you can timestamp changing versions of your work the moment inspiration hits, no matter the file type.
Signing a digital file should be as simple and private as signing on paper. But existing e-signature tools are built for enterprises, with complex workflows, server uploads, subscriptions, and vendor lock-in.
Whether you are protecting your next drop or signing a deadline-driven deal, OpenSig delivers lasting proof with the same flow.
Lock in authorship for every file you release, share, or pitch.
Add your e-signature to any document or file — simply and quickly.
We're co-designing OpenSig with a diverse early access cohort to make sure it works for solo creators and scaling teams alike.
Protect art, designs, and media before they ship.
Replace complex signing tools with a single verifiable receipt for pitch decks, plans, and IP documents.
Timestamp results, protect papers, and keep an auditable trail of research.
Preserve source material, drafts and media integrity before stories break.
Preserve contracts, agreements, and legal documents with proof of authenticity.
Ensure the integrity of medical records, research data, and compliance documents.
Three quick steps to capture proof of existence and possession.
We process your file privately on your device to capture its unique fingerprint.
No uploads, ever. Privacy is paramount.
Proof creation begins hereAdd an optional message then publish a proof, like an encrypted digital timestamp, directly from your device to a permanent public record.
No middleman. No account.
Proof of existenceAnyone with your file can verify the proof and read your encrypted message.
Anyone with your contact details can verify you created it.
Without the file, the proof reveals nothing.
Proof of possession confirmedTake a look at the MVP workflows we're refining with early adopters—from lightning-fast IP receipts to multi-signer approvals.
Only pay for signing — verification is always free and doesn't require the OpenSig app.
No complex workflows. Simply top up credits in the app to pay as you go. One credit per signature.
3 free
Your first 3 proofs are free.
5 proofs
Occasional proofs for personal creations and documents.
25 proofs
Regular proofs for professionals and small teams.
100 proofs
Frequent proofs for creators and professionals.
Contact us for custom plans and enterprise options.
OpenSig gives us a single source of truth for our originals and our deals. We can prove when something was created and who signed off—without changing how we work.
— Creative studio & early access partner
The OpenSig protocol, software libraries and proof registry are open-source, so you can audit, verify, or integrate freely. Explore our repositories on GitHub.
Your digital identity is built on open standards like ERC-4337, Decentralised Identifiers and Verifiable Credentials, ensuring portability across platforms. We use the excellent Nexus smart wallet implementation from Biconomy, which allows us to offer seamless upgrades and modular features.
The OpenSig mobile app itself is currently closed source while we explore features on top of the open protocol.
Tell us what you're protecting or signing and we'll tailor a walkthrough around your files, collaborators and timeline.