Glossary · Custody & Security
Hot Wallet
Also: hot wallets, online wallet
Published
Hot Wallet — A hot wallet is a wallet whose private keys are held on internet-connected systems so that it can sign transactions automatically and immediately. It offers the highest availability and the highest exposure to remote compromise, so institutions keep hot wallet balances small and tightly monitored.
Where Hot Wallets Are Necessary
Some flows must sign without a human in the loop: exchange withdrawal processing, automated on-chain settlement, and payment networks that run continuously. A hot wallet serves those flows because it can sign the moment a rule is satisfied. The trade-off is that the key material is reachable by whatever can reach the system that holds it.
Limiting the Exposure
Institutions treat a hot wallet as a float, not a store. It holds only the balance the next hours of activity require, with automated top-ups from warmer tiers and sweeps of excess back to them. Withdrawal allow-lists, velocity limits, anomaly detection, and hardware-backed key protection reduce what a compromise could take. Independent audits and penetration tests verify the controls.
Hot, Warm, Cold
The three tiers form a spectrum of availability against exposure. A custody program states how much sits in each tier, what controls apply, and how funds move between them, and it treats the hot tier as the part of the estate most likely to be attacked.