When it comes to smart contracts, most of people assume that they are already built with automation. Actually, smart contracts are not smart enough.
The reason for this lack of automation lies in the Ethereum Virtual Machine (EVM) itself: programs only run for a few milliseconds at a time; persistent loops or “cron” jobs that constantly repeat themselves, typical in traditional operating systems, limit a miner from ever completing the state transition and thus mining a block.
As a result, these programs, called smart contracts, are limited to only storing state and logic. Without an outside impulse, they are functionally inactive. In order to execute their logic and to change their state, they require an external party to send a transaction to them in the first place.
Learn how to automate your smart contract in a 5-min tutorial video:
And you can find the docs here: https://docs.gelato.network/guides/tutorial