Ledger API

Coming soon

The hosted Ledger API is not available yet. A basic file-backed local ledger ships today (init, append, proof, latest, trust-config); the hosted log service, witnesses, and mirrors are on the roadmap. The reference below previews the planned API.

The Ledger API exposes the append-only transparency log. It never stores document contents - only compact, salted commitments and signed tree heads.

Get the latest signed tree head

bash

curl https://ledger.osdfsystems.com/v1/sth

json

{  "tree_size": 184203,  "root_hash": "SHA-256:beef…",  "timestamp": "2026-02-11T17:04:00Z",  "signature": "base64url…",  "witnesses": ["witness-eu-1", "witness-us-2"]}

Fetch an inclusion proof

bash

curl "https://ledger.osdfsystems.com/v1/proof/inclusion?leaf=SHA-256:c0de…&size=184203"

Fetch a consistency proof

bash

curl "https://ledger.osdfsystems.com/v1/proof/consistency?from=184000&to=184203"

Verification

Clients verify proofs locally with domain-separated hashing:

text

leaf = SHA-256(0x00 || canonical_entry_bytes)node = SHA-256(0x01 || left || right)

Witness cosignatures detect a log that attempts to present a split view.

For the live, working proof API and the osdf ledger command workflow (anchor, proof, verify, consistency), see Ledger & CLI.