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.
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?
Thanks! If you run into anything or have questions about the API, happy to help. The quickest way to try it is the curl example in my comment above — no signup needed.
Thanks, "missing primitive" is exactly how I think about it too.
On idempotency: not solved yet at the API level. Each POST creates a new document so a retry would create a duplicate. Adding an idempotency key header is on the roadmap, it becomes essential once agents run unsupervised. For now the MCP tool response includes the document_id so agents can check status before retrying.
On markdown vs PDF: almost entirely markdown so far. Agents generate text naturally so markdown in is the obvious path. The pdf_url option exists for when you already have a templated doc from another system and just need the signing part.
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.
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 trailOne 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?
interesting and useful, i will really try this
Thanks! If you run into anything or have questions about the API, happy to help. The quickest way to try it is the curl example in my comment above — no signup needed.
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Thanks, "missing primitive" is exactly how I think about it too.
On idempotency: not solved yet at the API level. Each POST creates a new document so a retry would create a duplicate. Adding an idempotency key header is on the roadmap, it becomes essential once agents run unsupervised. For now the MCP tool response includes the document_id so agents can check status before retrying.
On markdown vs PDF: almost entirely markdown so far. Agents generate text naturally so markdown in is the obvious path. The pdf_url option exists for when you already have a templated doc from another system and just need the signing part.
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