A small tool for a job that got complicated.
Suresign sends a document out, collects signatures, and keeps the proof. That is the whole product, and keeping it that way is a decision we make again every time somebody asks for something.
Send it out. Get it back signed. Keep the proof.
Why it exists
It started with a familiar week. You agree the terms on a Tuesday and the document goes out. One person cannot open the attachment. Another prints it, signs it, and emails back a photo of it taken at an angle in bad light. A week later somebody asks whether it was ever signed, and no one is sure.
The tools built to fix this are good, and they are built for large companies: per-seat pricing, an admin console, a training session. That is a lot of ceremony for a lease that needs signing by Friday. So we built the small one, and we would rather it did three things you never have to think about than thirty you have to learn.
What we care about
A few things more than features: that you never have to wonder who has opened your document, that your documents are encrypted before they are stored, and that every signature carries a record nobody can quietly edit.
How we make money
One way: a flat monthly price once you send more than the free plan allows. Nobody pays per signature, the people signing never pay, and we do not sell data, run advertising, or train models on your documents.
What it runs on
Every service we rely on, and what we do to keep your documents safe on it.
- Hosting
- The app runs on Vercel. Every request travels over TLS: plain HTTP is redirected to HTTPS, and HSTS is set.
- Database
- Accounts, document details and the audit trail live in PostgreSQL on Neon, encrypted at rest and reachable only over TLS.
- Files
- We encrypt each document with AES-256-GCM before it is stored on Cloudflare R2, so the storage provider holds ciphertext, not readable documents.
- Proof
- Every step is written to an append-only, hash-chained audit trail. A completed document is sealed with a certificate, and its hash joins a public record anyone can check.
- Signing invitations, reminders and finished copies go out through Resend.
- The agent
- The agent runs on Anthropic's models, only when someone in your workspace uses it. Under its terms Anthropic may not train its models on what it reads.
- Payments
- Paid plans will be billed through Polar, once checkout opens. Card details go to them directly and never reach our servers.