A hot wallet is a cryptocurrency wallet connected to the internet so it can send funds quickly. That convenience makes it useful for exchanges, payment services, and other systems that need fast withdrawals or frequent transfers. The tradeoff is exposure: because the wallet or its signing environment is online, it is easier for attackers to target through stolen credentials, malware, API abuse, or compromised admin access.
In cyber security, hot wallets matter because they often hold the funds that criminals most want to move and cash out. Defenses focus on reducing what stays online and tightening control over every transfer. Common protections include keeping only a small balance in hot storage, using multi-signature approval, separating duties, enforcing withdrawal limits, and monitoring for unusual transaction patterns. Cold storage is typically used for larger reserves because it is much harder to reach remotely.