Smart contracts are self-executing contracts containing the terms and conditions of an agreement among peers. The terms and conditions of the agreement are written into code. The smart contract executes on the Ethereum blockchain's decentralized platform. The agreements facilitate the exchange of money, shares, property, or any asset. There are two widely-used programming languages for writing Ethereum smart contracts – Solidity and Serpent. 

• Solidity is a high-level programming language used for implementing smart contracts on the Ethereum blockchain platform. It enables blockchain developers to check the program at runtime rather than compile-time.
• Serpent is a smart contract language based on Python programming language. Serpent is currently being used for complex enterprise projects.

Traditionally, when two parties enter into a contract, they utilize the services of a trusted third party to execute the agreement. It's been done this way for centuries. However, the introduction of smart contracts and its related technologies is automating what has been a laborious manual process.