> For the complete documentation index, see [llms.txt](https://worldkoisan.gitbook.io/koisan-international-coin/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://worldkoisan.gitbook.io/koisan-international-coin/koisan-chain/dapp-development/remix.md).
# Remix
[Remix](https://remix.ethereum.org/) is an online tool for contract development and deployment.
## Firstly, go to `Remix`
In the left file browser, there are 3 folders under the example project default\_workspace:
* contracts：For contract file storage.
* scripts：For script file storage.
* tests：For test file storage.
We can refer to the sample project to create a new project.
## Edit Contract
Click file, such as `1_Storage.sol`, contents are editable on the right side.
## Compile Contract
1. Click the left button to switch to Compile interface;
2. Set related compilation options;
3. Click the compile button to compile.
If you need to compile another contract, you must switch back to the file browser, select a new contract, and then switch to `Compile` interface to compile.
## Deploy Contract
To deploy a compiled contract on chain, a browser wallet plug-in is required. Taking `MetaMask` for instance:
Install `MetaMask` plug-in on browser, set network information, and save the above setting.
* Mainnet
```
rpc: https://rpc.koisan-chain.com
chainID: 312
symbol: KIC
explorer: https://explorer.koisan-chain.com
```
.png?alt=media\&token=52c13253-af44-4fae-bd26-b0359679e541)
Switch back to `Remix` interface.
* Click the left button to switch to Deploy interface;
* Select 'injected Web3' and allow `MetaMask` to provide the execution environment;
* Click the deploy button.
The contract is ready to be deployed on chain once `MetaMask` is confirmed.
## Interaction
With the contract deployed successfully, the deployed contract can be viewed under `Deployed Contracts`. Open contract and click the button to invoke contract method.
The interaction with the contract differentiates between writing data and reading data: Writing data is called a transaction, while reading data is defined as a call.
* Transactions: Fundamentally, it changes the state of the network. It can be a normal transaction, or a contract that is deployed or invoked. It takes gas to execute a transaction, and a certain amount of time for a transaction to be uploaded. Each transaction has a unique transaction hash.
* Calls: It does not cost gas to execute the code on the network and just reads data.
In the figure below, the yellow button initiates a transaction and the blue button initiates a call.
