# Understanding contracts Contracts in the AppLayer network are custom, developer-made classes that directly interact with the current State of the Blockchain. This chapter will comprehensively cover creating native contracts for AppLayer using the BDK, as well as operating the AppLayer EVM to leverage existing Solidity contracts. AppLayer ensures that contracts deployed in its network, no matter the type, remain compatible with existing frontend Web3 tools (e.g. [MetaMask](https://metamask.io/), [ethers.js](https://github.com/ethers-io/ethers.js/), [web3.js](https://docs.web3js.org/), etc.). Those are originally designed to interact with Solidity contracts and thus require a similar interface. To call your contract's functions from a frontend, you'll also need to generate its ABI - you can either do it directly with our generator tool if coding a pre-compiled contract (explained further), or replicate their definitions in Solidity and use an external tool like Ethereum's [Remix](https://remix.ethereum.org/) or any other of your preference. This ABI can then be used by your preferred Web3 frontend. --- # 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.applayer.com/testnet/understanding-contracts.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.