JSON-RPC

Arc namespace

Two methods that exist nowhere else. One tells you which build answered, the other proves a block was final.

Do not feature-detect with rpc_modules

The arc namespace is registered outside the standard module registry, so rpc_modules never lists it. The methods work regardless. Call them and handle the error rather than gating on a capability list that will always answer no.

arc_getVersion

Returns the execution build: git_version, git_commit, git_short_hash and cargo_version. Use it to pin observed behaviour to a build during an incident, and to assert in CI that staging and production run the same release.

http

POST /v1/$KEY
{"jsonrpc":"2.0","id":1,"method":"arc_getVersion","params":[]}

{
  "git_version": "v0.8.0",
  "git_commit": "…",
  "git_short_hash": "…",
  "cargo_version": "…"
}

arc_getCertificate

Takes a height and returns the consensus commit certificate for it: the round, the block hash and the validator signatures. This is the finality proof for a block, and the only artefact on Arc that evidences settlement without trusting whoever answered the call.

http

POST /v1/$KEY
{"jsonrpc":"2.0","id":1,"method":"arc_getCertificate","params":["0x4f21a0"]}

{
  "height": 5185952,
  "round": 0,
  "block_hash": "0x4f21…a0c",
  "signatures": [{ "validator": "0x…", "sig": "0x…" }]
}

We cache every certificate and index it by transaction hash as well as by height, which is what the settlement proof endpoint serves.