---
title: "Cosmos RPC Proxy"
method: POST
path: "/api/rpc/{chainId}"
tags: ["RPC"]
---

# Cosmos RPC Proxy

`POST /api/rpc/{chainId}`

JSON-RPC 2.0 proxy to the Cosmos RPC of a supported Cosmos chain. The request and response follow the standard [JSON-RPC 2.0 specification](https://www.jsonrpc.org/specification).

Only a limited set of RPC methods is supported:
- `status` — fetch the node status. `params` must be `{}`.
- `abci_query` — query application state. `params` must include `data` (string), `path` (string), and `prove` (boolean). Allowed `path` values:
  - `/cosmos.auth.v1beta1.Query/Account`
  - `/cosmos.bank.v1beta1.Query/AllBalances`
  - `/cosmos.tx.v1beta1.Service/Simulate`
- `broadcast_tx_sync` — broadcast a signed transaction. `params` must contain a single `tx` field (string).
- `tx_search` — search for transactions. `params` must include `page` (string, only `"1"` is allowed) and `query` (string, must match `tx.hash='<64-hex>'`).

Any other method or unsupported parameter shape returns a `400` error.

## Path parameters

- `chainId` string, required

## Request body

- object
  - `id` integer, required — JSON-RPC request ID.
  - `method` 'status' | 'abci_query' | 'broadcast_tx_sync' | 'tx_search', required — RPC method name.
  - `params` object, required — RPC method parameters. The expected shape depends on `method`.

## Response `200`

Successful response

- object
  - `jsonrpc` string — JSON-RPC protocol version.
  - `id` integer — Echoed request ID.
  - `result` object — RPC method result.

## Other responses

- `400` — Bad request — unsupported chain, method, or parameter shape.

## Changes

- **2026-05-27** `a90ced4ee47e` — 1 info
  - endpoint added
- **2026-03-25** `8f391fd6e76c` — 1 breaking
  - api path removed without deprecation

[Change history](https://skmtc.dev/initia-labs/apis/router-api/changes/api/rpc/:chainId/post.md)

---

[API](https://skmtc.dev/initia-labs/apis/router-api.md) · [All operations](https://skmtc.dev/initia-labs/apis/router-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/initia-labs/router-api/revisions/d69782928523/schema)