Sign once. Verify forever.
The first e-signature platform anchored to Bitcoin AND Polygon — two independent public networks. Open verification spec. Open-source CLI. Tamper-proof for decades.
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Free plan available · No credit card required
Integrates with 24+ tools you already use
Trusted by teams in high-compliance industries
How it works
Six steps to legally binding, multi-anchor-verified signatures.
Upload Your Document
Drag and drop any PDF, DOCX, or image. Our AI auto-detects signature zones and form fields.
Encrypt & Store
AES-256 encryption at rest, TLS 1.2+ in transit. Stored in AWS S3 with server-side encryption and key management.
Invite Signers
Add recipients by email. Set signing order, access codes, and 2FA requirements for each signer.
Sign with Verification
Signers authenticate and apply their signature. IP address, timestamp, and user agent captured for legal validity.
Multi-Anchor Audit Trail
Every action extends a SHA-256 hash chain. The Merkle root anchors to Bitcoin (via OpenTimestamps, every plan) and Polygon (Pro+) — two independent public networks, two independent proofs.
Legally Binding · Independently Verifiable
Completed documents are ESIGN, UETA, and eIDAS compliant. The verification spec is open. The CLI is open source. Anyone can confirm using only public Bitcoin and Polygon nodes.
Everything you need for secure document signing
Enterprise-grade features designed for teams that handle sensitive documents.
Immutable Hash Chain
Every action from upload to final signature creates a SHA-256 hash chain. Tampering with any step invalidates the entire record.
AI-Powered Field Detection
Upload a PDF and our AI identifies signature zones, date fields, and form areas automatically. Set up signing in seconds, not minutes.
Open-Source Verification
Anyone can verify a signed document against public Bitcoin and Polygon data — using our open-source CLI (npm install -g @zdottedline/verify). No account needed. Verification runs directly against public networks.
Legally Binding Signatures
Compliant with ESIGN Act and UETA. eIDAS Advanced Electronic Signature support. Every signature captures IP, timestamp, and user agent for legal validity.
Multi-Party Signing
Sequential or parallel signing workflows. Set the order, add access codes, require 2FA. Handle complex signing ceremonies with ease.
Complete Audit Trail
Every view, click, and signature is logged with immutable timestamps. 7-year retention meets eIDAS Advanced Electronic Signature requirements.
Encrypted Cloud Storage
Documents encrypted at rest with AES-256. Access only through time-limited signed URLs. Your files never leave your control.
Document Templates
Create reusable templates with pre-placed fields. Send contracts, NDAs, and agreements in seconds with consistent formatting.
Real-Time Status Updates
Know the instant a document is viewed, signed, or declined. Live WebSocket updates keep your team in the loop.
The shift
Incumbent e-signature
Trust, conditional.
Your proof is a PDF certificate generated by their backend and vouched for by their logs. If their logs are wrong, or gone, or subpoenaed, your proof is whatever they say it is.
zdottedline
Proof, unconditional.
Every envelope extends a SHA-256 hash chain. The Merkle root anchors to Bitcoin (via OpenTimestamps) and Polygon — two independent public networks. Decades from now, anyone with the signed PDF and the .ots proof can hash, walk, and confirm authenticity against public Bitcoin and Polygon nodes — with or without us.
Verify
Don't take our word. Take the chain's.
Every signed document carries two independent proofs (Bitcoin .ots file + Polygon tx hash). Run our open-source CLI — npm i -g @zdottedline/verify — and it walks the hash chain locally, reads the Polygon anchor from any public RPC, and confirms the OpenTimestamps proof against any public Bitcoin node. No account. No login. No zdottedline required.
Open spec · MIT-licensed CLI · github.com/zdottedline/zdl-verify
Sign something that lasts.
Start with three free signed documents per month. Bitcoin-anchored on every plan. Send the verification link to anyone who needs to check — or hand them the open-source CLI.