When you trade crypto without a middleman, you’re using a decentralized exchange, a platform that lets users swap tokens directly from their wallets without relying on a company to hold their funds. Also known as a DEX, it’s the backbone of DeFi—and Uniswap v2 was the version that made it mainstream. Launched in 2020, Uniswap v2 didn’t just improve on its predecessor—it redefined how people thought about trading crypto. Instead of order books like traditional exchanges, it used something called an automated market maker, a system that sets prices based on the ratio of tokens in a pool, not buyer-seller bids. Also known as an AMM, this model removed the need for market makers and opened trading to anyone with a wallet and some tokens.
Uniswap v2’s magic was in its simplicity. You didn’t need to sign up, verify your identity, or deposit funds into a central account. Just connect your wallet, pick two tokens, and swap. Behind the scenes, it relied on liquidity pools, reserves of token pairs locked in smart contracts that enable instant trades. Also known as liquidity provision, this system let everyday users earn fees by adding their tokens to these pools. If you added ETH and DAI to a pool, you’d get a share of every trade made between those two tokens. It was a win-win: traders got cheap, fast swaps, and liquidity providers earned passive income. But it wasn’t perfect. The same mechanism that made trading easy also exposed users to impermanent loss, a risk where the value of your deposited tokens drops compared to just holding them, due to price swings in the pair. Also known as liquidity risk, this became a major lesson for new DeFi users.
Uniswap v2 also introduced support for new tokens—anything with an ERC-20 standard could be traded. No approval needed. No gatekeepers. That freedom led to a flood of new projects, both real and fake. It also made it easier for scams to hide in plain sight. Today, most of the volume has moved to Uniswap v3 and other DEXes with better capital efficiency. But v2 didn’t disappear. It’s still running, still trading millions daily, and still the blueprint for almost every DEX that came after it. If you want to understand how DeFi truly works, you start here.
Below, you’ll find real reviews, risks, and lessons from users who traded on Uniswap v2—some made money, others lost it. You’ll see how it connects to today’s scams, regulatory crackdowns, and even the rise of privacy-focused chains. This isn’t just history. It’s the foundation of everything you trade today.
Uniswap v2 on Optimism offers low fees and fast swaps for beginners, but it's being replaced by v3. Learn who should use it, what the risks are, and how to get started in 2025.