ISCC C2PA Resolver

Warning

Experimental (beta, MVP). This service and its documentation are provided as is, without warranty of any kind. The API, the gateway contract and the public instances may change in breaking ways before version 1.0.

A C2PA Soft Binding Resolution API for the ISCC fingerprint io.iscc.v0. It recovers lost C2PA Manifests by content: a client sends the ISCC of a file that lost its Content Credentials, the resolver searches the ISCC Discovery Protocol for declarations of similar content whose gateway URL is the address of a C2PA Manifest, and returns those manifests as matches. It follows the Soft Binding Resolution API of the upcoming C2PA specification 2.5, whose OpenAPI document still carries version 2.4.0.

Network	Resolver	Search backend
Mainnet	https://c2pa.iscc.io	https://search.iscc.io
Testnet	https://c2pa-test.iscc.io	https://search-test.iscc.id

Quick look

curl "https://c2pa-test.iscc.io/v1/matches/byBinding?alg=io.iscc.v0&value=<percent-encoded base64 ISCC-SEQ>"

{
  "matches": [
    {
      "manifestId": "urn:c2pa:F9168C5E-CEB2-4FAA-B6BF-329BF39FA1E4",
      "endpoint": "https://c2pa-test.iscc.io/v1/iscc/maigkv5faaxoxyab",
      "similarityScore": 93,
      "isccId": "ISCC:MAIGKV5FAAXOXYAB"
    }
  ]
}

Then GET {endpoint}/manifests/{manifestId} returns the C2PA Manifest Store.

What it implements

• GET and POST /v1/matches/byBinding for io.iscc.v0, with values as specified in IEP-0020
• GET /v1/iscc/{isccId}/manifests/{manifestId}: the manifest of a match, linked by its endpoint, without stored state
• GET /v1/manifests/{manifestId}: the same for clients that ignore endpoint, for matches of the last hour
• GET /v1/services/supportedAlgorithms, /capabilities, /status and /.well-known/c2pa-soft-binding-resolution
• Open access, no store or bindings routes; it passes the C2PA Soft Binding API conformance harness
• A file check on the landing page: it reads and validates the Content Credentials of a file in the browser, then searches for C2PA Manifests of the same content, with the file's own io.iscc.v0 soft binding or, after the visitor confirms the upload, an ISCC computed by web.iscc.io

Repositories become findable by declaring their assets with the manifest address on their Soft Binding Resolution API (https://…/manifests/{manifestId}) as gateway URL. See the documentation for the API, the gateway contract, scoring, operations and development.

Development

uv sync
uv run prek install
uv run poe all      # format, type check, test with 100% coverage
uv run poe serve    # http://127.0.0.1:45460

License

Apache-2.0. Documentation CC BY 4.0.