Blockchain timestamp & proof of existence for any file
Someone stole your work? Prove you created it first.
Once they publish your design, code, or idea as theirs, the burden of proof shifts to you. ProofSnap timestamps any file with blockchain — proof it existed on a specific date. $4.99. No uploads. Done in seconds.
7 days free, then from $4.99 (one-time) or $8.99/mo
From $4.99 (one-time) · No file upload — hash computed locally · Works with any file type
File certification is included in every ProofSnap plan. ProofSnap also captures full web pages as forensic evidence — screenshots, HTML, metadata, blockchain timestamps, and chain of custody. Learn more about web evidence →
Available on Chrome Web Store · No access to your personal data · Installs in 30 seconds
How file certification works
Three steps. Your file never leaves your device.
Drag & drop your file
Open ProofSnap and drag any file into the extension. Documents, images, code, designs, audio, video — any file type works.
SHA-256 hash computed locally
ProofSnap computes a SHA-256 hash of your file entirely in your browser. Your file never leaves your device — only the 64-character hash is used.
Hash anchored to Bitcoin blockchain
The hash is anchored to the Bitcoin blockchain via OpenTimestamps. A provenance certificate PDF is generated as your proof of existence.
6 reasons creators, developers & businesses timestamp their files
Any file where you need to prove “this existed on this date, in this exact form.”
Copyright & IP Protection
Prove you created it first. Timestamp your manuscript, song, design, photograph, or source code before publishing.
What is digital provenance? →Contracts & NDAs
Timestamp the signed version. If terms are disputed later, your blockchain-certified copy proves what was agreed on what date.
Code Provenance
Timestamp your git commits, releases, or security audits. Prove your code existed in a specific state on a specific date.
Academic Research
Establish priority of discovery. Timestamp your findings, datasets, or pre-prints before peer review.
Design & Creative Work
Prove your design, logo, or artwork existed before a competitor's version. Blockchain timestamp = prior art.
Deepfake Countermeasure
Certify original media before it can be manipulated. The provenance certificate proves your file is the authentic original.
Deepfake evidence & provenance certificates →Without proof of when you created it, you have nothing.
These disputes happen every day. The creator who can prove the earliest date wins.
Freelancer sends logo concepts to client. Client ghosts, then uses the design without paying. Without a timestamp proving the designer created it first, it's their word against the client's.
Common in: graphic design, branding, UX/UI
Business partner claims the NDA was different from what was signed. Without a timestamped copy of the exact version they signed, courts treat it as he-said-she-said.
Common in: partnerships, vendor agreements, employment
Developer builds a tool, co-founder claims ownership. Git history can be rewritten. A blockchain timestamp of the original codebase proves who wrote it and when — immutably.
Common in: startups, open source, freelance dev
The cost of NOT timestamping: legal fees, lost IP, disputed contracts. The cost of timestamping: $4.99. Once.
What you get per certified file
Every file certification generates a complete evidence package — blockchain timestamp, digital signature, provenance certificate, and chain of custody.
provenance_certificate.pdf
Provenance proof (6 checks)
evidence.pdf
Evidence summary PDF
manifest.json.ots
Bitcoin blockchain timestamp
manifest.sig
Digital signature (RSA-4096)
manifest.json
SHA-256 hashes of all files
publickey.pem
Verification public key
forensic_log.json
Complete forensic log
chain_of_custody.json
Verifiable chain of custody
Your original file + all certification files download as a ZIP. eIDAS qualified timestamp available on Enterprise plan (EU legally binding, 27 member states).
Your file NEVER leaves your device
ProofSnap computes the SHA-256 hash locally in your browser using the Web Crypto API. Only the hash — a 64-character string — is sent for timestamping. Not your file. Not a preview. Not metadata. Just the hash. Zero privacy risk.
How ProofSnap compares
OriginStamp shut down in May 2025. ScoreDetect requires cloud upload and charges monthly. ProofSnap processes locally and starts at $4.99 one-time.
| Feature | ProofSnap | ScoreDetect | OriginStamp |
|---|---|---|---|
| Price | $4.99 one-time | $11.31/mo | SHUT DOWN |
| Files included | 5–50/mo (plan) | Limited | — |
| Blockchain | Bitcoin (OTS) | Bitcoin | Bitcoin |
| eIDAS qualified | Enterprise plan | No | No |
| Provenance cert | Yes (6 checks) | No | No |
| Web capture too | Yes | No | No |
| Local processing | Yes | Cloud upload | Cloud upload |
Legal validity of blockchain timestamps
Blockchain timestamps are recognized as valid evidence in Italy (Law 12/2019, Art. 8-ter — recognizes distributed ledger timestamps), China (Supreme People's Court ruling, September 2018 — blockchain evidence admissible in Internet courts), and several US states including Vermont, Arizona, and Illinois. In the EU, qualified electronic timestamps under eIDAS Art. 41 enjoy a legal presumption of accuracy across all 27 member states. ProofSnap offers eIDAS qualified timestamps on the Enterprise plan.
Just need to certify a few files? This is all you need.
SnapPack: $4.99 — 5 file certifications
One-time payment. All features. Credits never expire. Includes 5 file certifications + 5 web captures.
Prove it's mine — from $4.99Need ongoing certifications? Monthly plans
7-day free trial on all plans. Cancel anytime.
Essential
100 web captures/mo
- File certification — 5/mo
- Provenance certificate
- Capture process video
- Blockchain timestamp
- EU qualified timestamp (eIDAS)
Professional
200 web captures/mo
- File certification — 15/mo
- Everything in Essential
- Blockchain (OpenTimestamps)
- EU qualified timestamp (eIDAS)
Enterprise
Unlimited web captures
- File certification — 50/mo
- Everything in Professional
- EU qualified timestamp (eIDAS)
- Priority support
Annual plans save 20%. See all pricing options
7 days free, then from $4.99 (one-time) or $8.99/mo
Not sure? Download sample evidence package (ZIP)