The first e-signature platform built for AI agents. Send documents for signing from Anthropic Cowork, any MCP client, or a simple API call.
No setup wizards, no training sessions. If you can talk to Claude, you can send documents for signature.
Download the SendSign plugin and drag it into Cowork. Your API key is pre-configured. That's the entire setup.
30 seconds"Send this MSA to alex@partner.co for signature." Claude uploads the document, places signature fields, and sends the signing link.
One sentence"Has Jane signed the NDA yet?" Get status updates, send reminders, and download the fully executed document — all from Cowork.
InstantSendSign was designed for AI agents first. Every capability is available as a natural language command.
Ask Claude to draft an NDA, MSA, or offer letter — it generates the document with signature blocks already in place. No manual field placement. Ever.
Use Cowork's Legal plugin to review and redline a contract. When you're done, say "send this for signature" — SendSign picks it up and sends it. Review and execution in one conversation.
"I need to sign it too." Your signature is applied via the API — you never leave Cowork. The other party gets the partially-executed doc with your signature already on it.
Place fields once — it's a template forever. "Save this layout as our Standard NDA template." Next time, just say the template name and the recipient. Fully automatic.
"Remind them after 3 days if they haven't signed." Set it and forget it. Escalating reminders at intervals you choose, with sender notification when things go overdue.
"What's my signing status?" Get a structured overview of everything pending, overdue, and recently completed. Know who's holding things up before your first meeting.
Natural language commands. No syntax to learn. Just tell Claude what you need.
"Send this NDA to jane@acme.com for signature"
Upload and send a document for signing
"Send the SOW to procurement — sign my part first"
Self-sign before sending to counterparty
"Send this to alice@co.com, bob@co.com, and carol@co.com"
Multi-party signing with routing order
"Bulk send this offer letter to all 12 candidates"
Bulk send with per-recipient customization
"Draft a mutual NDA between us and Globex Inc"
Generate a document with signature fields placed
"Create an offer letter for the senior engineer role"
Generate from description with smart field placement
"Generate an MSA using our standard terms"
Generate from saved templates
Coming soon
"Review this contract with Legal, then send for signature"
Cowork Legal integration — review → sign flow
Coming soon
"Has Jane signed the NDA yet?"
Check status of any envelope
"Give me a briefing on all pending signatures"
Morning briefing — pending, overdue, completed
"Send a reminder to the unsigned parties on the MSA"
Manual nudge for outstanding signatures
"Download the fully executed NDA"
Get the final signed PDF with certificates
"Save this layout as our Standard NDA template"
Save field placement as reusable template
"Send our Standard NDA to the new vendor"
Use a saved template by name
"Set up reminders at 3, 7, and 14 days"
Configure automatic follow-up cadence
"Void the envelope — we're going with a different vendor"
Cancel an in-progress envelope
Coming soon
"Show me all templates"
List and manage saved templates
Coming soon
Full-featured e-signatures with an API-first architecture designed for automation.
17 MCP tools out of the box. Works with Cowork, Claude Code, and any MCP-compatible client. No custom integration needed.
Three endpoints to create, send, and check status. Usage-based, no per-seat pricing. Webhook notifications for every event.
Compliant with ESIGN Act (US) and eIDAS (EU). Electronic consent capture, IP recording, and tamper-evident audit trails.
Signatures are embedded directly into the PDF. The signed document is a standalone file — no special viewer needed.
Every signed document includes a certificate with SHA-256 hash, signer details, IP addresses, timestamps, and consent records.
Real-time notifications for every event: sent, viewed, signed, completed, voided. Integrate with any workflow.
Create once, reuse forever. Templates store document layouts, field positions, and signer roles. Fully automatic from Cowork.
Send the same document to hundreds of recipients at once. Each gets their own signing link and independent tracking.
Full source code on GitHub under AGPL-3.0. Self-host on your own infrastructure with zero usage limits. Audit every line.
All documents and signatures encrypted using AES-256 in your storage layer. Keys managed per-tenant for isolation.
Every connection — API calls, signing ceremonies, webhook deliveries — encrypted with TLS 1.3. No exceptions.
Every signed document includes a SHA-256 hash in the completion certificate. Tamper detection is built in — any modification breaks the hash.
Every action logged with timestamp, IP address, and user agent. Consent records for each signer. Exportable for compliance reviews.
PostgreSQL Row-Level Security ensures tenants can never access each other's data. Storage paths are tenant-prefixed. API keys are tenant-scoped.
Legally binding in the United States under the Electronic Signatures in Global and National Commerce Act.
Valid electronic signatures across the European Union under the eIDAS regulation.
Every line of code is public. No security through obscurity. Verify the cryptography yourself.
We're not trying to replace DocuSign for Fortune 500 companies. We're building for the AI-native future.
| Feature | SendSign | DocuSign | Dropbox Sign |
|---|---|---|---|
| MCP / AI Agent Support | 17 MCP tools | No | No |
| Cowork Plugin | Native | No | No |
| AI Document Generation | Built-in | No | No |
| Self-Sign via API | Yes | No | No |
| Legal Review Integration | via Cowork Legal | CLM add-on ($$$) | No |
| Contract Generation | via Cowork | No | No |
| Open Source | AGPL-3.0 | No | No |
| Self-Hostable | Docker | No | No |
| REST API | Yes | Yes | Yes |
| Webhooks | All tiers | Yes | Yes |
| Templates | All tiers | Business Pro+ | Yes |
| Bulk Send | All tiers | Business Pro+ | Paid add-on |
| ESIGN / eIDAS | Yes | Yes | Yes |
| Audit Trail | Yes | Yes | Yes |
| SSO / SAML | White-label | Enterprise | Enterprise |
| Starting Price | Free / $29/user/mo | $10/user/mo | $15/mo |
| Per-Envelope Limits | Unlimited ($29) | 5/mo at $10 | Unlimited (1 user) |
No per-envelope fees. No hidden costs. No feature hostage-taking.
Run SendSign on your own infrastructure. Full source code, no limits, forever.
We host it. We maintain it. You send documents. That's it.
Your brand. Your domain. Commercial license. Enterprise compliance.
SendSign is open source under AGPL-3.0. Self-host on any machine with Docker. No vendor lock-in. No usage limits. Audit every line of code.
Star on GitHubQuestions about enterprise pricing, white-label, or partnerships? We'd love to hear from you.