The crypto fear index, often known as the Crypto Fear and Greed Index, is a metric used to measure the overall market sentiment toward cryptocurrencies. It combines various factors—such as price volatility, trading volume, social media activity, surveys, trends, and market dominance—to produce a single score between 0 and 100. Low scores indicate "fear," suggesting that investors are worried or risk-averse, while high scores indicate "greed," suggesting confidence or potential market overexuberance. It is commonly used as a contrarian indicator to gauge whether the crypto market might be undervalued or overvalued.