Remix, previously known as Browser Solidity, is a web browser based IDE that allows you to write Solidity smart contracts, then deploy and run the smart contract.

You can run Remix from your web browser by navigating to, or by installing and running in on your local computer.

Local Installation

Instead of running Remix from, you can download the latest package from . You will have to switch to the branch gh-pages. Download the .zip file with a name similar to into a directory on your computer. Unzip the .zip file. Load index.html in your browser.

The advantage of running Remix from your local computer is that it can communicate with an Ethereum node client running on your local machine via the Ethereum JSON-RPC API. You can then execute your smart contracts in Remix while connected to your local development blockchain, the Testnet blockchain, or the Mainnet blockchain.

The Remix Screen

Whether you are running Remix from it’s website, or from your local installation, you should see a screen resembling the one below.


Taking Remix For A Run

Sample Source Code

Following is the source code for a simple example that you can copy and paste into the left section of your Remix screen.

 1 pragma solidity ^0.4.8;
 3 contract Hello  {
 5     // A string variable
 6     string public greeting;
 8     // Events that gets logged on the blockchain
 9     event GreetingChanged(string _greeting);
11     // The function with the same name as the class is a constructor
12     function Hello(string _greeting) {
13         greeting = _greeting;
14     }
16     // Change the greeting message
17     function setGreeting(string _greeting) {
18         greeting = _greeting;
20         // Log an event that the greeting message has been updated
21         GreetingChanged(_greeting);
22     }
24     // Get the greeting message
25     function greet() constant returns (string _greeting) {
26        greeting = greeting;
27     }
28 }


Deploy Sample Source Code

On the right hand side, enter "Hello, World!" into the input box to the right of the Create button. Click on the Create button and your contract will be deployed to the JavaScript EVM. The constructor in the source code will be executed with the "Hello, World!" string passed as the parameter.

Your screen should resemble:

The first light blue block with the heading greeting shows that after you deployed the contract, the greeting variable has been set to "Hello, World!".

The second light blue block with the heading greet shows the results of executing the greet() function.


Execute Sample Source Code Function

Scroll down the right hand side of the page and enter "Hello from BokkyPooBah!" into the input box to the right of setGreeting. Click on the setGreeting button and the setGreeting(...) function will be executed with the "Hello from BokkyPooBah!" string passed as the parameter. You will also see the GreetingChanged event logged in the results.

If you now click on the greeting and greet button, the new value of the greeting will be displayed as shown below:


Some Remix Options

The Remix Settings Tab

The following screenprint shows the Remix Settings tab. Use this section to change the Solidity version and whether to enable or disable optimisation. You can also switch off the Auto Compile.


The Remix Transactions Tab

The following screenprint shows the Remix Transactions tab. Use this section to select from one of your Accounts, specify the amount of Gas supplied for the transaction and the amount of ethers to send from your specified account with the transaction.


The Remix Environment Tab

The following screenprint shows the Remix Environment tab. The default setting is to deploy and run your smart contract in the local JavaScript EVM. You can also select Web3 and connect to your local node via JSON-RPC.