Crypto glossary
Actively validated service (AVS)
An actively validated service (AVS) is a network or protocol secured by restaked ETH, whose operators can be slashed if they break its rules.
EigenLayer introduced the term for any system that needs its own validation but borrows Ethereum's economic security instead of launching a new token and validator set. Stakers restake ETH or liquid staking tokens, delegate them to operators, and those operators opt in to run the software of one or more AVSs, such as data availability layers, oracles, bridges or coprocessors.
For the service, restaking offers a large pool of collateral from day one. For stakers, each AVS adds rewards on top of normal staking yield. Other restaking platforms such as Symbiotic and Karak use similar ideas under different names, and the AVS model is a central piece of the shared-security narrative on Ethereum.
Every AVS defines its own slashing conditions, so the same ETH can be penalised for faults in several services at once, which stacks risks that are hard to price. A bug in an AVS's slashing logic could hit honest operators, and many services pay rewards in their own volatile tokens.
Example
An operator restaking 10,000 ETH opts in to a data availability AVS and an oracle AVS, earning fees from both but accepting that misbehaviour in either can cut its stake.