# Contract Security Checks Due to the nature of distributed apps it is very hard to fix bugs once the application is deployed. Hence, it is of great importance to ensure the app is running correctly and securely before deployment. Contract security reviews are done by specialised companies. They can be very costly which might be out of reach for single developers and start-ups. However, there are also automated services and programs that are free to use. The most popular are: * ​[Slither](https://github.com/crytic/slither), here's a[ tutorial](https://blog.trailofbits.com/2018/10/19/slither-a-solidity-static-analysis-framework/)​ * ​[MythX](https://mythx.io/)​ * ​[Mythril](https://github.com/ConsenSys/mythril)​ We recommend using at least one of these services if a professional contract security review is unaffordable or not possible. A more comprehensive look into secure development practices can be found[ here](https://github.com/crytic/building-secure-contracts/blob/master/development-guidelines/workflow.md). --- # 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.emoney.network/launching-your-dapp-on-e-money-network/contract-security-checks.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.