For New Devs: How to Build Your Own UniSwap Integration

Uniswap 101

Uniswap is the second-largest cryptocurrency Decentralized Exchange (DEX) in terms of Total Value Locked.

The protocol has step-by-step instructions for developers to build on-chain integrations with the DEX.

In this story, we’ll provide an overview of the instructions from Uniswap. We’ll cover:

1. Setting up a development environment
2. Writing a basic swap contract
3. Testing the contract
4. Finalizing the contract.

Setting Up a Development Environment

Uniswap allows developers to use different environment stacks when building. One of the common ones is Hardhat which runs nodes and provides a test framework. Alchemy is a tool for creating a Remote Procedural Call (RPC) -- that allows off-chain clients to communicate with a blockchain for building Decentralized Applications (dApps).

Start by cloning Uniswap’s sample project. This project can be found on the DEX’s GitHub. The selected test environment lets us Hardhat will then run a fork on Mainnet.

The next step is to fork the Ethereum Mainnet. The Hardhat environment can be advantageous in this step as it allows for running tests on the Ethereum node locally. That means the developer won’t incur gas fees for developmental testing. The benefit of using Hardhat is that it takes a snapshot of the project in a local node before refreshing, which secures the data.

Writing a Basic Swap Contract

The next step is to build the integration. Build your desired project or follow what Uniswap has provided in their post. When you have a completed contract, double-check to confirm that it conforms to these examples before testing it.

Testing the Contract

After building the contract, the developer has to test it. Use a testing framework like Chai to check how the contract is functioning. Check the tests recommended by Uniswap here and how to do them.

Finalizing the Contract

What’s next after developing your first contract? Uniswap recommends learning more by adding onto the contract, or cloning the repo to start again from scratch. Here are some advanced contract functions to try to create:

• Build a simple user interface
• Add an exact output swap function
• Write a general swap contract to swap between any ERC-20 pairs
• Write a program that feeds users with live prices
• Deploy the contract to a testnet
• Be creative!