The Scroll Alpha testnet is the latest and hottest thing amongst the zkEVM rollups that settle on the Ethereum L1 layer. In this beginner’s guide, we will understand how to use the Uniswap DAPP deployed on the Scroll Alpha testnet by their team!
Where?
You can find the DAPP here — https://uniswap-v3.scroll.io/#/swap
How?
First of all, please make sure that you are connected to the Scroll Alpha testnet. To do that, follow the instructions here or read my earlier guide on ‘Getting started with Scroll zkEVM.’
Step 1 — Wrapping ETH to WETH
Assuming that you have followed through with the instructions in my guide earlier, you should have a few ETH on the Scroll Alpha testnet now.
First, to get familiar with the Uniswap UI, let’s try ‘wrapping’ and ‘unwrapping’ WETH. The screens should look like these for the two swaps.
On the Scroll block explorer, these will be shown as ‘Withdraw’ and ‘Deposit’ transactions — https://blockscout.scroll.io/address/0xfA205A82715F144096B75Ccc4C543A8a2D4CcfaF
Step 2 — Get some USDC
Now that you know how to wrap and unwrap ETH, let’s get our hands on some USDC!
Please note that since this is a testnet, there might be a LOT of USDC and other so-called ‘stablecoins’ floating around. That is because on a testnet, anyone can create any random, arbitrary ERC20 token, call it USDC and give it any amount of ‘supply’. For this guide, you can very well choose any other ERC20 token, it doesn’t matter!
For this guide, I have chosen one such USDC token that seems popular and has some liquidity in the Uniswap pool. The address for this token is 0xA0D71B9877f44C744546D649147E3F1e70a93760.
Coming back to the Uniswap UI, for the second token, we need to choose this particular USDC token. For that, click on the second token dropdown and manually paste the above address in the popup and select this ‘USD Coin’. The screens should look like these —
Please note that while choosing USDC in the popup, Uniswap will show you a warning. You can safely ignore that on this testnet.
Also note that the ETH-USDC price in your case might be completely different than the screenshot above.
Step 3 — Add liquidity to the ETH — USDC pool
To add liquidity and get the coveted Uniswap NFT, go to https://uniswap-v3.scroll.io/#/pool and click the ‘New Position’ button.
The Add Liquidity popup has a lot of options, and I will not discuss that in this guide. Roughly, your choices should look like these —
For this beginner’s guide, the most important thing is to manage the Price Range such that you can see the ‘Preview’ button activated. Since this is a testnet and doesn’t reflect the price of USDC in real life, the range will vary wildly here. Also, because this pool doesn’t have a lot of liquidity, it can change quite often and quite drastically. Hence, don’t worry about that range. Just play around until you can add some liquidity.
The most important thing on this screen, for now, is the amount of liquidity you provide to this pool. Please ensure you don’t send all of your ETH since Goerli ETH is not readily available. You can send something like 0.01 or 0.02 ETH to get the hang of things!
Once you fill up all the correct values on the above popup, you must approve and submit a couple of transactions on Metamask. Once you do that, you should see a new position on your ‘Pools’ screen.
If you can click on this position, you will have an NFT associated with this position. The NFT looks beautiful, and you can do a bunch of things here —
Add liquidity
Remove liquidity
Collect your fees
You can even transfer/sell this NFT to someone else so that they obtain the liquidity position on this pool, though that is out of the scope of this guide.
Step 4 (optional) — Add liquidity on other pairs!
Now that you know how to use the Uniswap UI on Scroll, you can play around a bit more, try to find some other stablecoins with enough liquidity and add liquidity there!