@cosmjs/tendermint-rpc

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`

CosmJS

Concepts

Guides

API Reference

@cosmjs/tendermint-rpc

connectComet

CometClient

Version-Specific Clients

Tendermint37Client

Comet38Client

Comet1Client

Type Guards

RPC Clients

HttpClient

HttpBatchClient

WebsocketClient

Key Types

HttpEndpoint

RpcClient

BlockIdFlag

Date Utilities

Address Utilities

​connectComet

​CometClient

​Version-Specific Clients

​Tendermint37Client

​Comet38Client

​Comet1Client

​Type Guards

​RPC Clients

​HttpClient

​HttpBatchClient

​WebsocketClient

​Key Types

​HttpEndpoint

​RpcClient

​BlockIdFlag

​Date Utilities

​Address Utilities

connectComet

CometClient

Version-Specific Clients

Tendermint37Client

Comet38Client

Comet1Client

Type Guards

RPC Clients

HttpClient

HttpBatchClient

WebsocketClient

Key Types

HttpEndpoint

RpcClient

BlockIdFlag

Date Utilities

Address Utilities