Practical overview
When it fits
Use it when a command-line development workflow needs timestamp proofs for files or Git artifacts, particularly when the workflow can separate proof creation from later verification.
Who it is for
- Developers who want timestamp proofs for files or repository artifacts.
- Git users who need to timestamp PGP-signed commits or verify timestamps for commits and individual repository files.
Documented uses
- Create and retain an OpenTimestamps proof for a file.
- Verify whether a proof attests to a file's existence by a particular time.
- Timestamp PGP-signed Git commits and check timestamps for commits or individual files in a repository.
- Inspect a timestamp's commitment operations and attestations.
Requirements & limits
The documented installation paths are PyPI (`pip3 install opentimestamps-client`) and installation from source. Python 3 is required.
- Proof creation does not require a local Bitcoin node, but verification requires a local Bitcoin Core node; a pruned node is sufficient.
- Remote calendars assist timestamp creation, and newly submitted timestamps may remain pending for a few hours before Bitcoin confirmation.
- The client can timestamp several files in one command, but its documentation warns that closely timed or batched timestamps can expose relationships through metadata and similar commitment operations.
- The documentation says remote calendars receive opaque digests rather than file contents, while calendar communication itself does not currently attempt to provide privacy.
Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.
Create a timestamp proof for a file
Produce an OpenTimestamps proof alongside a file.
Before you start
- Python 3
- The OpenTimestamps Client installed via PyPI or from source
Steps
Run
ots stamp README.mdfor the file you want to timestamp.Keep the generated
README.md.otsproof file.Allow time for Bitcoin confirmation; an immediate verification may report that confirmation is pending.
Expected outcome
A `.ots` proof file is created with help from remote calendars and can be checked with the client.
Guide limitations
- Timestamp creation does not require a local Bitcoin node.
- New timestamps may take a few hours to be confirmed by the Bitcoin blockchain.
- Timestamping reveals timing metadata, and remote calendar communication does not currently attempt to provide privacy.
Verify a timestamp proof
Check a proof against Bitcoin and obtain its attested time.
Before you start
- Python 3
- The OpenTimestamps Client installed via PyPI or from source
- A local Bitcoin Core node; a pruned node is supported
Steps
Run
ots verify FILE.otsfor the proof.If required, provide the local node's JSON-RPC credentials using the documented
--bitcoin-nodeoption.Review the reported attestation or pending-confirmation status.
Expected outcome
The client reports whether the proof verifies and, when confirmed, identifies the Bitcoin block and attested time.
Guide limitations
- Verification requires a local Bitcoin Core node.
- Some incomplete timestamps need remote calendar assistance to obtain the Bitcoin block-header path.
Sources & review
Source record details
- Source availability
- Active
- Sources checked
- 17 October 2026
- Original website title
- opentimestamps/opentimestamps-client · Official homepage title · retained in its source language