Sign Documents with Full Control

Why OpenSig?

• Fully private and secure with the latest cryptography.
• No middlemen — sign directly on your phone using your own digital identity.
• No signups or accounts — just verify your email and your digital identity will be created.
• Nothing gets uploaded — everything stays local.
• No vendor lock-in — your identity is yours, forever.
• Signatures are cryptographically verifiable, even if OpenSig no longer exists.
• No hidden fees or crypto required.
• Email-based wallet recovery by default, with other options coming.

Use Cases

• IP Protection: Timestamp your documents, designs, videos, or inventions to prove authorship.
• E-Signatures: Sign contracts, proposals, or agreements with a verifiable digital signature.
• Business Workflow: Digitally sign any file with confidence, no matter the format.
• Notarize a public message: Declare something publicly; verifiable onchain forever.

How It Works

1. Verify your email to create your digital identity (smart wallet)
2. Sign, copyright and notarize privately — files are never uploaded
3. Top up with Apple Pay, Google Pay, or your card
4. Verify on-chain, forever

Screenshots

Open Source & On-Chain

Built on Polygon using ERC-4337 smart wallets from Biconomy.

• Powered by the OpenSig open source protocol.
• Gasless transactions via the OpenSig custom paymaster.
• Email recovery via interchangeable smart wallet module.