# Are smart contracts immutable? Smart contracts on the Ethereum blockchain are immutable, which means that once a smart contract is deployed on the Ethereum blockchain network, the code cannot be changed by anyone. Specifically, this immutability characteristic does not allow for any modifications and/or reversal subsequent to the deployment of the smart contract to the blockchain. However Smart Contracts can hold data which, depending on how they are programmed, can be changed. This is true even for immutable contracts. It is this facility which allows for the construction of Upgradeable Proxy Contracts. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.chainargos.com/documentation/concept-glossary/smart-contracts/are-smart-contracts-immutable.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.