Document integrity you can prove
We built Zdottedline because the world needs e-signatures that don't depend on trusting a single company.
Why Zdottedline Exists
Every year, billions of documents are signed electronically. But every major e-signature platform asks you to take their word that a document hasn't been tampered with. What happens when that company is breached? When their servers go down? When they change their terms?
Zdottedline was founded on a simple principle: document integrity should be mathematically provable, not based on corporate promises. By anchoring every signature event to two independent public networks — Bitcoin (via OpenTimestamps, free tier included) and Polygon (Pro+ tier) — and publishing the full verification spec on GitHub, we create proof that holds up even if our servers are temporarily down, or any single chain has issues.
Our Core Principles
Cryptographic Truth
We don't ask you to trust us — we give you math. Every document action generates a SHA-256 hash. The Merkle root anchors to Bitcoin (via OpenTimestamps) AND Polygon — two independent public networks — creating proof that exists outside our control.
Privacy by Design
Documents are encrypted at rest with AES-256 and in transit with TLS 1.2+. For maximum privacy, our enterprise zero-knowledge option encrypts documents in your browser before upload — we never see the plaintext.
Legal Validity
Fully compliant with the ESIGN Act, UETA, and eIDAS regulation for Advanced Electronic Signatures. Every signature captures IP address, timestamp, user agent, and geolocation for the legal evidence courts require.
Radical Transparency
The verification spec is published on GitHub. The CLI is open source and MIT-licensed. Anyone can confirm a document's integrity using only public Bitcoin and Polygon nodes — no Zdottedline account or login required. github.com/zdottedline/zdl-verify
Enterprise Infrastructure
Built on AWS with multi-availability-zone redundancy, automated backups, and disaster recovery. CloudWatch monitoring, GuardDuty threat detection, and WAF protection ensure 99.9% uptime for workloads of any scale.
Built for Everyone
Whether you're a solo consultant sending an NDA or a Fortune 500 company processing thousands of contracts daily, Zdottedline scales with you. Bitcoin anchoring is universal — every plan, including free. Polygon and zero-knowledge encryption are available on Professional+ for buyers who need instant on-chain proof or client-side encryption.
How Zdottedline Compares
Traditional e-signature platforms like DocuSign, Adobe Sign, and PandaDoc store your audit trail on their servers. If their infrastructure is compromised — or if they're acquired, change their terms, or simply go away — your proof of signing goes with them. Zdottedline takes a fundamentally different approach: we anchor document hashes to TWO independent public networks (Bitcoin and Polygon), publish the verification spec, and ship the verification tool as open source — so the proof exists, and remains verifiable, completely outside our control.
| Feature | Zdottedline | Others |
|---|---|---|
| Integrity proof | Bitcoin + Polygon, open spec | Server-only, vendor-locked |
| Encryption at rest | AES-256 + optional zero-knowledge | AES-256 |
| Verification | Open-source CLI, no account needed | Vendor portal only |
| Audit trail | Immutable hash chain + dual-anchor Merkle root | Database records |
| Offline verification | Yes — .ots proof + public Bitcoin/Polygon nodes | No |
| Compliance | ESIGN, UETA, eIDAS AES, GDPR, HIPAA ready | ESIGN, UETA |
Ready to get started?
Sign your first document with multi-anchor cryptographic integrity. Three free signed documents per month, no card required.