A generic JS client for the Websocket, high-level (Cosmos) and low-level (Tendermint) APIs

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This package implements a generic JS client wrapper for the Tendermint RPC, Tendermint WebSocket, and Cosmos SDK APIs.


npm install client-js


import Client from '@starport/client-js'

const client = new Client({
                  apiAddr: 'http://localhost:1317',        // Replace with Cosmos API node address
                  rpcAddr: 'http://localhost:26657',       // Replace with Tendermint RPC node address
                  wsAddr: 'ws://localhost:26657/websocket' // Replace with Tendermint WS node address

The client implements EventEmitter, runs a periodic connectivity test, and emits the following events based on the connection state:
  • 'api-status' : true/false
  • 'rpc-status' : true/false
  • 'ws-status' : true/false

You can listen for and handle those events in your app in the standard way:
client.on('api-status', (status) => { 
  // Handle API status here
client.on('rpc-status', (status) => { 
  // Handle RPC status here
client.on('ws-status', (status) => { 
  // Handle WS status here

The client also provides methods to switch the nodes used in an existing instance:

The client automatically subscribes to new block events and emits the events for handling:
client.on('newblock',(block) => {
  //handle incoming block here

Additional features

The client provides a useSigner() method to connect a signer or wallet using the CosmJS OfflineDirectSigner interface.
To access the resulting CosmJS signing client, use the .signingClient property. To access the signer, use the .signer property.
Using the client .switchRPC() method reinstantiates the signing client appropriately.
const signer = await DirectSecp256k1HdWallet.fromMnemonic(mymnemonic) // or any other object implementing the OfflineDirectSigner interface

await client.useSigner(signer)

const [account] = await client.signer.getAccounts();

const recipient = "cosmos1xv9tklw7d82sezh9haa573wufgy59vmwe6xxe5";

const amount = {
  denom: "uatom",
  amount: "1",

const result = await client.signingClient.sendTokens(account.address, recipient, [amount], "Memo Message");

Finally, the client provides two querying methods for the Cosmos SDK API:


A basic wrapper around Axios. For example, to query the bank module for an address's balances:
let balances = await client.query('/cosmos/bank/v1beta1/balances/','cosmos1xv9tklw7d82sezh9haa573wufgy59vmwe6xxe5');


    body: body,
    path: path,
    query: query,
    method: method,

This helper method is compatible with the swagger-typescript-api API classes that are generated with --single-http-client by using their Swagger definitions if the generated API classes exist for your chain endpoints.