@cosmjs/tendermint-rpc

Tendermint/CometBFT RPC client for HTTP and WebSocket

Low-level RPC client for communicating with Tendermint/CometBFT nodes. Supports HTTP and WebSocket transports, and auto-detects the node version.

npm install @cosmjs/tendermint-rpc

connectComet

Auto-detects the CometBFT/Tendermint version and returns the appropriate client.

function connectComet(endpoint: string | HttpEndpoint): Promise<CometClient>

import { connectComet } from "@cosmjs/tendermint-rpc";

const client = await connectComet("https://rpc.my-chain.network");
const status = await client.status();

CometClient

CometClient is a union type of all version-specific clients: Tendermint37Client | Comet38Client | Comet1Client. They share these methods:

Method	Parameters	Returns
status	—	Promise<StatusResponse>
block	height?: number	Promise<BlockResponse>
blockResults	height?: number	Promise<BlockResultsResponse>
blockchain	minHeight?: number, maxHeight?: number	Promise<BlockchainResponse>
tx	params: TxParams	Promise<TxResponse>
txSearch	params: TxSearchParams	Promise<TxSearchResponse>
validators	params: ValidatorsParams	Promise<ValidatorsResponse>
broadcastTxSync	params: BroadcastTxParams	Promise<BroadcastTxSyncResponse>
broadcastTxAsync	params: BroadcastTxParams	Promise<BroadcastTxAsyncResponse>
broadcastTxCommit	params: BroadcastTxParams	Promise<BroadcastTxCommitResponse>
abciQuery	params: AbciQueryParams	Promise<AbciQueryResponse>
disconnect	—	void

Version-Specific Clients

Tendermint37Client

For Tendermint 0.37 nodes.

Method	Parameters	Returns
connect (static)	endpoint: string | HttpEndpoint	Promise<Tendermint37Client>
create (static)	rpcClient: RpcClient	Tendermint37Client

Comet38Client

For CometBFT 0.38 nodes.

Method	Parameters	Returns
connect (static)	endpoint: string | HttpEndpoint	Promise<Comet38Client>
create (static)	rpcClient: RpcClient	Comet38Client

Comet1Client

For CometBFT 1.x nodes.

Method	Parameters	Returns
connect (static)	endpoint: string | HttpEndpoint	Promise<Comet1Client>
create (static)	rpcClient: RpcClient	Comet1Client

Type Guards

Function	Parameters	Returns
isTendermint37Client	client: CometClient	client is Tendermint37Client
isComet38Client	client: CometClient	client is Comet38Client
isComet1Client	client: CometClient	client is Comet1Client

These are TypeScript type predicates, so the compiler narrows the client type in the branch where the guard returns true.

RPC Clients

Low-level HTTP and WebSocket implementations.

HttpClient

Standard HTTP client for request/response RPC.

Method	Parameters	Returns
constructor	endpoint: string | HttpEndpoint, timeout?: number	HttpClient
execute	request: JsonRpcRequest	Promise<JsonRpcSuccessResponse>
disconnect	—	void

HttpBatchClient

Batches multiple RPC requests into a single HTTP call.

Method	Parameters	Returns
constructor	endpoint: string | HttpEndpoint, options?: Partial<HttpBatchClientOptions>	HttpBatchClient
execute	request: JsonRpcRequest	Promise<JsonRpcSuccessResponse>
disconnect	—	void

interface HttpBatchClientOptions {
  dispatchInterval: number;
  batchSizeLimit: number;
  httpTimeout?: number;
}

WebsocketClient

WebSocket client for streaming subscriptions.

Method	Parameters	Returns
constructor	endpoint: string, onError?: (err: any) => void	WebsocketClient
execute	request: JsonRpcRequest	Promise<JsonRpcSuccessResponse>
listen	request: JsonRpcRequest	Stream<SubscriptionEvent>
connected	—	Promise<void> (resolves when the socket is connected)
disconnect	—	void

Key Types

HttpEndpoint

interface HttpEndpoint {
  readonly url: string;
  readonly headers: Record<string, string>;
}

RpcClient

interface RpcClient {
  readonly execute: (request: JsonRpcRequest) => Promise<JsonRpcSuccessResponse>;
  readonly disconnect: () => void;
}

BlockIdFlag

enum BlockIdFlag {
  Unknown = 0,
  Absent = 1,
  Commit = 2,
  Nil = 3,
  Unrecognized = -1,
}

Date Utilities

Function	Parameters	Returns
fromRfc3339WithNanoseconds	str: string	DateWithNanoseconds
toRfc3339WithNanoseconds	date: ReadonlyDateWithNanoseconds	string
fromSeconds	seconds: number, nanos?: number	DateWithNanoseconds
toSeconds	date: ReadonlyDateWithNanoseconds	{ seconds: number; nanos: number }

Address Utilities

Function	Parameters	Returns
pubkeyToAddress	type: "ed25519" | "secp256k1", data: Uint8Array	string
pubkeyToRawAddress	type: "ed25519" | "secp256k1", data: Uint8Array	Uint8Array
rawSecp256k1PubkeyToRawAddress	pubkeyData: Uint8Array	Uint8Array
rawEd25519PubkeyToRawAddress	pubkeyData: Uint8Array	Uint8Array