Alchemy Set-up for Macs

**Get access to Alchemy for free **here.
Estimated time to complete this guide: ~5 minutes** **
For a quick start, you can interact with Ethereum nodes using JSON RPC shell commands. This can be quite manual, and you can write POST requests, GET requests, or others. See examples here.
Rather than writing out requests manually, you can use Web3 to interact with the Ethereum blockchain. Web3 is a collection of libraries that allow you to connect to a node using HTTP, WebSockets, or IPC. You can use Web3 libraries in whichever language you are most comfortable with, the most common being Javascript, Java, and Python.
1. Install NodeJS and NPM
First, install Homebrew. Homebrew is a great installation software for macs so you can easily download other packages in the future. To install Homebrew, open Terminal and run:
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/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
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Next, install NodeJS and npm using Homebrew (npm will be installed with Node):
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brew install node
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You can now run Javascript in Terminal:
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node
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2. [Optional] Install Alchemy Web3
There are tons of Web3 libraries you can integrate with Alchemy, however, we recommend using Alchemy Web3, a drop-in replacement for web3.js, built and configured to work seamlessly with Alchemy. This provides multiple advantages such as automatic retries and robust WebSocket support.
In Terminal on the command line:
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npm install @alch/alchemy-web3
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3. [Optional] Install WebSockets
WebSockets are a great way to subscribe to events and changes, learn more through our Using WebSockets page. To use WebSockets, first install WebSocket cat.
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npm install -g wscat
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Now connect to Alchemy's blockchain infrastructure using WebSockets:
Using Alchemy's demo:
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wscat -c wss://eth-mainnet.ws.alchemyapi.io/ws/demo
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Using your own key:
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wscat -c wss://eth-mainnet.alchemyapi.io/ws/<api-key>
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Create a Web3 instance and set your provider as Alchemy:
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const web3 = new Web3("wss://eth-mainnet.ws.alchemyapi.io/ws/demo");
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4. Start Building!
Now that you have everything you need installed, start building your first app. Here are a couple great starting points:
1.Write your first web3 script​
2.Check out the Demo App we seeded in your Alchemy dashboard
3.Follow this tutorial to create a smart contract!

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Choosing a Web3 Network

Last modified 5mo ago

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Contents

1. Install NodeJS and NPM

2. [Optional] Install Alchemy Web3

3. [Optional] Install WebSockets

4. Start Building!