Uni is a service coin of the Uniswap project, based on the Ethereum blockchain (ERC20). Uniswap has become a popular protocol due to the development of Defi (decentralized finance), it automates the trading of Defi tokens and maintains their liquidity.
The total issue of UNI is limited to 1 billion tokens. They are gradually put into circulation over a period of 4 years. Once all tokens are unlocked Uniswap will launch an inflation containment mechanism - a "constant inflation rate" of 2% to maintain the network.
You have to understand that UNI is an ERC-20 token, which means that to transfer them to other users you need ETH to pay transaction fees, which on the etherium network are high.
UNIs are traded on all major crypto exchanges. Investors can buy UNI tokens on several exchanges including Binance, Bitfinex, Coinbase Pro, Gemini, Huobi, Kucoin and Uniswap itself. The token has been very successful and made the top 50 coin lists just a few weeks after launch.