How to Add Legal-Grade Timestamps to Any File in 5 Lines of Python

C Grx — Fri, 27 Feb 2026 14:49:00 +0000

Last year, a client ghosted me after I sent them design files. Two months later, I saw my work on their website. I had no proof I created it first.
So I built an API that solves this. One call, and you get a court-admissible proof of existence.
The problem
You create something. You share it. Someone steals it. How do you prove you made it first?
Screenshots? Timestamps on your hard drive? Email to yourself? None of that holds up.
The solution: 5 lines of Python
pythonimport hashlib, requests

with open("my_file.pdf", "rb") as f:
file_hash = hashlib.sha256(f.read()).hexdigest()

r = requests.post("https://certify.sbix.io/api/certify",
headers={"Authorization": "Bearer YOUR_API_KEY"},
json={"leaves": [file_hash], "leaves_hashed": True})

print(r.json())
Response in < 3 seconds:
json{
"proof_id": "proof_a1b2c3d4e5f6g7h8",
"eidas_qualified": true,
"tsa_type": "eIDAS Qualified",
"merkle_root": "e8d5baba90968ce9..."
}
What just happened?

Your file was hashed locally — it never left your machine
The hash was timestamped with an eIDAS Qualified RFC-3161 timestamp (legally binding in 27 EU countries)
The proof was anchored on the Tezos blockchain — immutable, public, forever
A backup was stored on Aleph Cloud — decentralized, no single point of failure

You now have a proof that your file existed at that exact moment. If anyone steals your work, you have court-admissible evidence.
What you get
Every proof includes:

PDF certificate with QR code for instant verification
RFC-3161 timestamp token (.tsr file)
Blockchain anchor on Tezos (verifiable on tzkt.io)
Evidence Pack — 8-file ZIP that verifies offline. No internet needed. No account needed.

The Evidence Pack includes verify.sh and verify.py scripts. If SBIX disappears tomorrow, your proof still works with standard tools (OpenSSL + sha256sum).
Public verification
Anyone can verify a proof without an account:
bashcurl https://certify.sbix.io/api/v1/verify/proof_a1b2c3d4e5f6g7h8
json{
"success": true,
"data": {
"verified": true,
"has_eidas": true
}
}
Use cases

Freelancers: Certify deliverables before sending to clients
Developers: Timestamp your code before open-sourcing
Photographers: Prove you took the photo before sharing
Legal: Court-admissible evidence in 27 EU countries
Anyone: Prove any file existed at a specific date

Pricing

Free: 5 proofs/month (no credit card)
Pro: $29/month — unlimited proofs + Evidence Pack
Legal: $49/month — eIDAS Qualified + court-ready bundle

API docs: https://certify.sbix.io/api-reference
Try it: https://certify.sbix.io
Built on EU sovereign infrastructure (AS30077). No US jurisdiction. Your data never leaves Europe.

I'm a solo founder building this from Cyprus. Happy to answer any questions in the comments.

DEV Community: C Grx

How to Add Legal-Grade Timestamps to Any File in 5 Lines of Python