Show HN: Signbee – An API that lets AI agents send documents for signature
Show HN (score: 5)
Found: March 16, 2026
ID: 3792
Description
API/SDK
Show HN: Signbee – An API that lets AI agents send documents for signature
Hi HN,
I built Signbee while working on AI agents that handle contracting workflows.
The agents could draft agreements, negotiate terms, manage deals — but the
moment a signature was needed, the workflow broke. It always ended with
"please upload this to DocuSign" — which meant human intervention, account
setup, and manual uploads.
So I built a simple API. You POST markdown and Signbee generates the PDF,
or you pass a URL to your own PDF if you already have one designed the way
you want it. No templates, no editor. Either way, it verifies both parties
via email OTP and produces a signed document.
curl -X POST https://signb.ee/api/v1/send \
-H "Content-Type: application/json" \
-d '{
"markdown": "# NDA\n\nTerms...",
"sender_name": "You",
"sender_email": "you@company.com",
"recipient_name": "Client",
"recipient_email": "client@co.com"
}'
Under the hood:
- Markdown → PDF generation, or bring your own PDF via URL
- Both parties verified via email OTP
- Timestamps and IP addresses recorded
- Final document hashed with SHA-256
- Certificate page appended with full audit trail
One interesting challenge: the certificate page itself is part of the
document that gets hashed, so any modification — even to the certificate
— invalidates the integrity check.
I also built an MCP server (npx -y signbee-mcp) so tools like Claude
or Cursor can call it directly.
Curious to hear from people who've dealt with document signing systems or
automated agent workflows — what would you want to automate?
https://signb.ee
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