A timestamping proof standard

OpenTimestamps aims to be a standard format for blockchain timestamping.

Stamp & Verify

Drop here a file to stamp
OR
an .ots proof file to verify

The hash is calculated on your browser preserving your privacy. More...
Timestamping proof download will start automatically after uploading document.

How it Works

A timestamp proves that some data existed prior to some point in time. OpenTimestamps defines a set of operations for creating provable timestamps and later independently verifying them. At the time of writing timestamping on the Bitcoin blockchain is supported, the format is flexible enough to support a variety of methods. More.

Anyone could realize a timestamp with the permissionless blockchain by paying the transaction fees, for your convenience we offer calendar servers that perform this operation for you. These servers are free to use and they don't require any registration or api key.

Python

Javascript

Java


$ pip3 install opentimestamps-client
$ ots stamp my-file


$ npm install -g javascript-opentimestamps
$ ots-cli.js stamp my-file


$ git clone https://github.com/opentimestamps/java-opentimestamps
$ cd java-opentimestamps
$ mvn install
$ java -jar target/OtsCli.jar stamp my-file

Calendars

The following are the, free to use, default calendars used by OpenTimestamps. They rely on donations to reduce maintainers efforts, they accept bitcoin and some accept lightning network payments. Check the calendars uptime.

Alice

Bob

Finney

Catallaxy