ThetaSwap is the first decentralized exchange built on Theta blockchain, using an open-source smart contract system built based on Automated Market Maker logic similar to that of UniSwap. It allows users to exchange their newly-created TNT20 tokens built on Theta blockchain in a trustless, non-custodial way.
You can find ThetaSwap here: https://swap.thetatoken.org/
ThetaSwap uses your Theta Chrome Wallet to interact with the exchange. You can download that here to add to your Chrome browser. To import your existing Theta web wallet or mobile wallet into the Theta Chrome Wallet, just use your 12-word mnemonic phrase you recorded at wallet setup.
To set up a new trading pair on ThetaSwap, you'll need to create a liquidity pool. A liquidity pool is a pool of TFUEL and a given TNT20 token that allows users to trade against it. As a buyer or seller, I can trade TFUEL for that TNT20 token or vice versa. A liquidity provider that creates the pool earns a fee of 0.3% of each transaction that uses the liquidity they provide. For information on creating a liquidity pool for your token, see here.
Version 1 of ThetaSwap allows trading of TFUEL and TNT20 tokens, but future versions will add functionality for THETA trading via a version of the THETA token in a TNT20 wrapper (similar to wETH or wBTC which you may have used in other DeFi protocols, this would be wTHETA). Several stablecoins issuers have also expressed interest in bringing their assets to Theta blockchain in TNT20 form, making it even easier to trade on ThetaSwap. Look for continued upgrades to ThetaSwap along the way to Mainnet 3.0 launch in April.
Updated about a year ago