EigenLayer is a restaking marketplace on Ethereum that lets ETH validators and LST holders opt‑in to provide crypto‑economic security to external ‘Actively Validated Services’ (AVSs). Participants earn additional yield by subjecting their stake to slashing conditions defined by each module, creating a shared‑security layer similar to Polkadot’s parachains. Mainnet restaking went live in April 2024, and over 4 million ETH had been opt‑in restaked by Q2 2025.