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Infura Web Socket Intro


Infura’s websocket endpoint provides support for Pub/Sub API as well as JSON-RPC filter support. Additionally, the regular Ethereum JSON-RPC API is also supported over a websocket connection and documented in the ‘EXAMPLE’ portion for each ‘Ethereum JSON-RPC’ call.

All examples in this reference section uses wscat, but will work with any tool that supports websockets.

Some tools you can use for making these requests

Websocket authentication by Project ID

Websocket subscription requests should include your PROJECT_ID in the websocket API url.

wscat -c wss://mainnet.infura.io/ws/v3/YOUR-PROJECT-ID

Websocket authentication by Project ID and Project Secret

Subscriptions initiated from a secure environment can include the Project Secret as shown below:

wscat -c wss://mainnet.infura.io/ws/v3/YOUR-PROJECT-ID --auth ":YOUR-PROJECT-SECRET"


The following is an example showing a connection to the websocket endpoint and using subscriptions through web3.js 1.0.

NOTE: web3.js 1.0.0-beta.34 has an open issue with request headers (https://github.com/ethereum/web3.js/issues/1559); use version 1.0.0-beta.36 or newer or revert to version 1.0.0-beta.33 to avoid this issue.

const Web3 = require("web3");

let web3 = new Web3(
  // Replace YOUR-PROJECT-ID with a Project ID from your Infura Dashboard
  new Web3.providers.WebsocketProvider("wss://mainnet.infura.io/ws/v3/YOUR-PROJECT-ID")

const instance = new web3.eth.Contract(<abi>, <address>);

    { fromBlock: "latest", toBlock: "latest" },
    (errors, events) => {
        if (!errors) {
            // process events
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