---
title: "JSON-RPC endpoint for ARC methods"
method: POST
path: "/"
tags: ["ARC"]
---

# JSON-RPC endpoint for ARC methods

`POST /`

Single JSON-RPC 2.0 POST endpoint. Methods currently implemented under the `arc` namespace:

  1. arc_getCertificate(height: u64 | hex string) -> RpcCommitCertificate
     Returns the consensus commit certificate for the specified height if available.
     The height parameter accepts either a decimal number (7) or a hex quantity string ("0x7").
     Error Mapping (error.code -> meaning):
       -32602 Invalid params (height < 1)
       -32004 Not found (no certificate upstream)
       -32005 Upstream unreachable (connect errors)
       -32603 Internal (timeout / decode / generic upstream HTTP status)
     Curl Examples:
       curl -s -X POST -H 'Content-Type: application/json' \
         --data '{"jsonrpc":"2.0","method":"arc_getCertificate","params":[7],"id":1}' \
         http://127.0.0.1:8545
       curl -s -X POST -H 'Content-Type: application/json' \
         --data '{"jsonrpc":"2.0","method":"arc_getCertificate","params":["0x7"],"id":1}' \
         http://127.0.0.1:8545

  2. arc_getVersion() -> RpcVersionInfo
     Returns version/build information for the node execution layer.
     Fields:
       git_version: Git tag or short commit hash
       git_commit: Full git commit hash
       git_short_hash: Short git commit hash
       cargo_version: Cargo package version
     Curl Example:
       curl -s -X POST -H 'Content-Type: application/json' \
         --data '{"jsonrpc":"2.0","method":"arc_getVersion","params":[],"id":1}' \
         http://127.0.0.1:8545

NOTE: This path '/' is shared by all JSON-RPC methods; separate request/response schemas are provided for clarity.

## Request body

- union
  - JsonRpcRequestArcGetCertificate
    - `jsonrpc` '2.0', required
    - `method` 'arc_getCertificate', required
    - `params` union[], required
      - union
        - integer
        - string — Hex-encoded quantity (e.g. "0x7"). Must be >= 1.
    - `id` union, required
      - integer
      - string
  - JsonRpcRequestArcGetVersion
    - `jsonrpc` '2.0', required
    - `method` 'arc_getVersion', required
    - `params` unknown[], required
      - unknown
    - `id` union, required
      - integer
      - string

## Response `200`

JSON-RPC success or error response for any listed method

- union
  - JsonRpcSuccessArcGetCertificate
    - `jsonrpc` '2.0', required
    - `id` union, required
      - integer
      - string
    - `result` RpcCommitCertificate, required
      - `height` integer, required
      - `round` integer, required
      - `block_hash` string, required
      - `signatures` RpcCommitSignature[], required
        - `address` string, required
        - `signature` string, required — Base64-encoded bytes
  - JsonRpcSuccessArcGetVersion
    - `jsonrpc` '2.0', required
    - `id` union, required
      - integer
      - string
    - `result` RpcVersionInfo, required
      - `git_version` string, required
      - `git_commit` string, required
      - `git_short_hash` string, required
      - `cargo_version` string, required
  - JsonRpcError
    - `jsonrpc` '2.0', required
    - `id` union, required
      - integer
      - string
    - `error` ErrorObject, required
      - `code` integer, required
      - `message` string, required

---

[API](https://skmtc.dev/circle/apis/arc-rpc.md) · [All operations](https://skmtc.dev/circle/apis/arc-rpc/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/circle/arc-rpc/revisions/071b64366e91/schema)