GlossaryConcept
Automated Market Maker (AMM): What Is It? Definition & Explanation
An automated market maker (AMM) is a decentralized exchange (DEX) mechanism that prices assets using a mathematical formula and liquidity pools, instead of the traditional order book that matches buyers and sellers. Users trade directly against the pool.
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An automated market maker (AMM) is one of the cornerstones of decentralized finance (DeFi). It removes the order-book model used by traditional exchanges, instead pricing assets automatically through a mathematical formula and liquidity pools.
What Is It?
On a traditional exchange, buying an asset requires a counterparty who wants to sell it (order-book matching). An AMM changes this model: users trade not against a counterparty but directly against a liquidity pool. Uniswap, Curve, and Balancer are the best-known AMM-based DEXs.
How Does It Work?
Most AMMs use the "constant product" formula x * y = k, where x and y represent the amounts of the two assets in the pool, and k is a constant value. When a user removes asset X from the pool and adds asset Y, the formula automatically calculates the new price. The larger the trade, the greater the price impact (slippage). Liquidity providers (LPs) deposit assets into the pool and earn a share of the trading fees.
Why Does It Matter?
AMMs made DeFi possible by letting anyone provide liquidity and swap tokens without permission. They offer a market infrastructure that runs 24/7 without a central intermediary and is censorship-resistant and transparent.
Risks
The best-known risk of AMMs is impermanent loss: when the price ratio of the assets in a pool changes, a liquidity provider can lose value compared to simply holding the assets. There are also risks of smart-contract vulnerabilities, high slippage in low-liquidity pools, and flash loan-based price manipulation.
| Feature | Detail |
|---|---|
| Model | Formula instead of order book |
| Core Formula | x * y = k (constant product) |
| Liquidity | Liquidity pools (LPs) |
| Examples | Uniswap, Curve, Balancer |
| Primary Risk | Impermanent loss + slippage |
Chart showing how a swap on the x * y = k curve in a liquidity pool determines price
COINOTAG Perspective
For COINOTAG, automated market makers are the key to understanding how decentralized liquidity works. The depth, volume, and fee structure of an AMM pool are important metrics that indicate the health of on-chain liquidity for a given token.
Frequently Asked Questions
What is the difference between an AMM and an order book?
In the order-book model buyers and sellers are matched; in an AMM, users trade not against a counterparty but directly against a liquidity pool, and the price is set by a mathematical formula.
What does the x * y = k formula mean?
It is the constant product formula used by most AMMs; x and y represent the amounts of the two assets in the pool, and k is a constant value. Swaps keep this constant while automatically setting the new price.
What is impermanent loss?
Impermanent loss is when the price ratio of the assets in a liquidity pool changes, causing the liquidity provider to lose value compared to simply holding the assets.
What are some example AMMs?
The best-known AMM-based decentralized exchanges include Uniswap, Curve, and Balancer.