A warm wallet is an intermediate crypto custody layer that sits between a hot wallet and cold storage. It is more accessible than offline storage, so funds can be moved faster for operations, but it is kept under tighter control than a fully Internet-connected hot wallet. Exchanges and custodians use warm wallets to balance liquidity, speed, and security.
From a security perspective, warm wallets matter because they can still be reached by attackers if credentials, signing systems, or internal workflows are compromised. In real attacks, this layer is often targeted alongside hot wallets because it contains assets that are available for rapid transfer. Defenses include limiting balances, separating signing authority, using multi-step approvals, monitoring unusual transfers, and isolating key-management systems. If a warm wallet is exposed, the impact can spread quickly even when cold reserves remain untouched.