Prove a document existed on a given day, for free
OpenTimestamps anchors your file's fingerprint to Bitcoin for free. Only the fingerprint leaves your device.
- 5 minutes
- 3 steps
- Free
- easy
Bitcoin can prove the day you wrote something, for free, without the file ever leaving your laptop.
Chapter 1 · The wall
The wall you hit
Anyone can claim they wrote it first. Bitcoin can prove when you did, for free.
Chapter 2 · The power
What changes now
OpenTimestamps anchors your file's fingerprint to Bitcoin for free. Only the fingerprint leaves your device.
Chapter 3 · Do it
Do it yourself
Do it with me
Do it here, step by step
4 stepsabout 6 minFree
- 1Open opentimestamps.org and drop in your file 2 min
- 2Download the small .ots proof file and keep it with the original 2 min
- 3Come back after a few hours to upgrade the proof once Bitcoin confirms 1 min
- 4Prove it worked 1 min
- Open opentimestamps.org and drop in your file.
- Download the small .ots proof file and keep it with the original.
- Come back after a few hours to upgrade the proof once Bitcoin confirms.
- 5 min
- Free
- easy
Wallet or sign-in will not open in here? Open OpenTimestamps in a new tab ↗
Chapter 4 · Prove it
Prove it worked
Anyone can check your file against the proof without trusting you or the site.
Chapter 5 · Next star
Your next star
- Publish · 10 min · Files under about 100 KiB are free through ArDrive Turbo; larger ones cost a one-time feePublish a page that stays online without a hostArweave stores data with a one-time payment designed for permanence; ArDrive gives a simple upload app.Go to this star →
- Own · 10 min · The protocol is free; you pay network gas, usually a fraction of a cent on Base and other L2sGive or get a work reference that lives onchainThe Ethereum Attestation Service lets anyone sign a public statement about a wallet, such as 'delivered this project', that anyone can verify later without asking the signer.Go to this star →
Chapter 6 · Build
Build what is missing
A deed vault that timestamps on Bitcoin and collects witness attestations in one step.
Who could build it Families with land papers and nobody to trust.
Questions
How long does it take to prove a document existed on a given day, for free?
About 5 minutes, in 3 steps. The first step is: Open opentimestamps.org and drop in your file.
What does it cost?
Free. Start with the free parts, and never put in more than you can afford to lose.
Do I need to be technical?
It is rated easy. OpenTimestamps anchors your file's fingerprint to Bitcoin for free. Only the fingerprint leaves your device.
How do I know it worked?
Anyone can check your file against the proof without trusting you or the site.