Ethereum Alarm Clock is a decentralized protocol for scheduling Ethereum blockchain transactions to execute at a specified future time or block. Built on Ethereum smart contracts, it lets users define transaction details and provide payment for gas costs in advance. The service is designed to operate without privileged access for any party, and its code is open source under the MIT license.

Scheduled transactions are executed by TimeNodes, off-chain agents that act as counterparties and can earn a profit for carrying out the work. The project provides a TimeNode app for Linux, macOS, and Windows, along with guidance for setting up and funding an agent. Its integration-friendly, base-layer approach is intended to support simple transfers as well as more complex smart contract automation.

Ethereum Alarm Clock has been associated with ChronoLogic and featured in integration efforts involving MyCrypto and RSK. Potential uses highlighted by the project and its contributors include recurring payments, multi-step transactions, trading activity, and other automated blockchain actions.