yew/website/versioned_docs/version-0.21/getting-started/build-a-sample-app.mdx

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---
title: 'Build a sample app'
---
Once you have the environment ready, you can either choose to use a starter template that contains
the boilerplate needed for a basic Yew app or manually set up a small project.
## Using a starter template
Install [`cargo-generate`](https://github.com/cargo-generate/cargo-generate) by following their installation instructions
then run the following command:
```shell
cargo generate --git https://github.com/yewstack/yew-trunk-minimal-template
```
## Setting up the application manually
### Create Project
To get started, create a new cargo project.
```bash
cargo new yew-app
```
Open the newly created directory.
```bash
cd yew-app
```
### Run a hello world example
To verify the Rust environment is set up, run the initial project using `cargo run`. You should see
a "Hello World!" message.
```bash
cargo run
# output: Hello World!
```
### Setting up the project as a Yew web application
To convert this simple command line application to a basic Yew web application, a few changes are needed.
#### Update Cargo.toml
Add `yew` to the list of dependencies.
```toml title=Cargo.toml
[package]
name = "yew-app"
version = "0.1.0"
edition = "2021"
[dependencies]
# this is the development version of Yew
yew = { git = "https://github.com/yewstack/yew/", features = ["csr"] }
```
:::info
You only need the feature `csr` if you are building an application.
It will enable the `Renderer` and all client-side rendering-related code.
If you are making a library, do not enable this feature as it will pull in
client-side rendering logic into the server-side rendering bundle.
If you need the Renderer for testing or examples, you should enable it
in the `dev-dependencies` instead.
:::
#### Update main.rs
We need to generate a template that sets up a root Component called `App` which renders a button
that updates its value when clicked. Replace the contents of `src/main.rs` with the following code.
:::note
The call to `yew::Renderer::<App>::new().render()` inside the `main` function starts your application and mounts
it to the page's `<body>` tag. If you would like to start your application with any dynamic
properties, you can instead use `yew::Renderer::<App>::with_props(..).render()`.
:::
```rust ,no_run, title=main.rs
use yew::prelude::*;
#[function_component]
fn App() -> Html {
let counter = use_state(|| 0);
let onclick = {
let counter = counter.clone();
move |_| {
let value = *counter + 1;
counter.set(value);
}
};
html! {
<div>
<button {onclick}>{ "+1" }</button>
<p>{ *counter }</p>
</div>
}
}
fn main() {
yew::Renderer::<App>::new().render();
}
```
#### Create index.html
Finally, add an `index.html` file in the root directory of your app.
```html , title=index.html
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<title>Yew App</title>
</head>
<body></body>
</html>
```
## View your web application
Run the following command to build and serve the application locally.
```bash
trunk serve
```
:::info
Add option '--open' to open your default browser `trunk serve --open`.
:::
Trunk will rebuild your application if you modify any of its source code files.
By default server will listening at address '127.0.0.1' and port '8080' => [http://localhost:8080](http://127.0.0.1:8080).
To change it, create the following file and edit as needed:
```toml title="Trunk.toml"
[serve]
# The address to serve on LAN.
address = "127.0.0.1"
# The address to serve on WAN.
# address = "0.0.0.0"
# The port to serve on.
port = 8000
```
## Congratulations
You have now successfully set up your Yew development environment, and built your first web application.
Experiment with this application and review the [examples](./examples.mdx) to further your learning.