---
title: "Fusion L2 JSON-RPC"
method: POST
path: "/rpc/{apiKey}"
tags: ["RPC"]
---

# Fusion L2 JSON-RPC

`POST /rpc/{apiKey}`

Proxies a JSON-RPC 2.0 request to the Fusion L2 OP-Geth node.
This route is for the Fusion L2 only. Only Fusion L2 methods are supported —
JSON-RPC for any other connected chain must go to the Fusion Proxy's multi-DLT
endpoint `/dlts/{dlt}/networks/{networkId}/rpc/{apiKey}` (see the fusion-proxy spec).

Authentication is accepted via the Overledger-issued API key as the
`{apiKey}` path segment, the `X-API-Key` header, or an
`Authorization: Bearer <jwt>` Keycloak token. The `X-API-Key` header
takes precedence over the others when present.

## Path parameters

- `apiKey` string, required

## Request body

- JsonRpcRequest
  - `jsonrpc` '2.0', required
  - `method` string, required
  - `id` union, required
    - string, nullable
    - integer, nullable
  - `params` unknown[]
    - unknown

## Response `200`

JSON-RPC response (success or RPC-level error)

- union
  - JsonRpcResponse
    - `jsonrpc` '2.0', required
    - `id` union, required
      - string, nullable
      - integer, nullable
    - `result` unknown, required
  - JsonRpcError
    - `jsonrpc` '2.0', required
    - `id` union, required
      - string, nullable
      - integer, nullable
    - `error` object, required
      - `code` integer, required — Auth-related JSON-RPC error codes returned by `/rpc/{apiKey}`: - `-32000`: "Missing credentials." (HTTP 401) - `-32001`: "Invalid credentials." (HTTP 403) - `-32002`: "Internal server error." (HTTP 500)
      - `message` string, required

## Other responses

- `401` — Missing credentials (JSON-RPC error code `-32000`)
- `403` — Invalid credentials (JSON-RPC error code `-32001`)
- `503` — OP-Geth node unavailable

---

[API](https://skmtc.net/overledger/apis/overledger-server.md) · [All operations](https://skmtc.net/overledger/apis/overledger-server/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/overledger/overledger-server/revisions/dd31e0a52064/schema)