Leaf as a micro-framework

Use Leaf as a lightweight micro-framework with no structure to build simple applications and APIs.

Micro-frameworks are lightweight, minimal, and focused—giving you just what you need to build fast without the overhead of a full-stack framework. Leaf is built for simplicity, speed, and ease of use, while offering more functionality than most micro-frameworks.

Unlike Leaf MVC, using Leaf as a micro-framework gives you complete flexibility. There's no enforced structure, so you can build your app however you like—perfect for small projects and APIs that don’t need strict separation of concerns.

Getting started

You can create a new Leaf app using the create command on the Leaf CLI.

Leaf CLI

bash

leaf create my-app --basic

Installing without the CLI

If you don't have the Leaf CLI installed, you can install Leaf using Composer.

bash

composer require leafs/leaf

You can then create a new Leaf app by creating a new index.php file and requiring the Leaf autoloader.

index.php

php

<?php

require __DIR__ . '/vendor/autoload.php';

app()->get('/', function() {
    response()->json(['message' => 'Hello, World!']);
});

app()->run();

Once you are in your application root, you can run the app using the serve command.

bash

php leaf serve

Your app is now running! Open http://localhost:5500 in your browser.

Building your first app

Now the fun begins! 🚀 With Leaf as a micro-framework, you have the freedom to build your app your way. Define routes, return JSON for an API, or use Blade to render views—it’s all up to you.

Here’s a quick example of a simple JSON API:

index.php

php

<?php

require __DIR__ . '/vendor/autoload.php';

app()->get('/', function() {
    response()->json(['message' => 'Hello, World!']);
});

app()->run();

It’s a start, but there’s so much more to build! You can now expand your app by adding more routes and features.

As a maker, the fastest way to get started is by building a Coming Soon, Early Access, or Pre-Launch page. This gives you something real to share while you build—helping you attract early users and generate interest.

Let’s create a simple pre-launch page using Leaf as a micro-framework.

1 Setting up our views

We've already seen how routes work by returning JSON in the previous example. Now, let’s render a view using Blade instead. Unlike Leaf MVC, Blade isn’t installed by default when using Leaf as a micro-framework—but don’t worry, setting it up is quick and easy!

Leaf CLIComposer

bash

leaf install blade@v4

bash

composer require leafs/blade:v4

Once Blade is set up, we can create a new view inside the views directory at the root of your app. By default, Leaf looks for views in this directory unless you configure a different path.

views/prelaunch.blade.php

blade

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Coming Soon</title>
    <style>
        body { text-align: center; padding: 50px; }
        h1 { font-size: 2.5rem; }
        p { font-size: 1.2rem; color: #555; }
        input { padding: 10px; width: 250px; }
        button { padding: 10px 15px; background: #333; color: #fff; border: none; cursor: pointer; }
    </style>
</head>
<body>
    <h1>Something amazing is coming soon!</h1>
    <p>Sign up to be the first to know when we launch.</p>
    <form action="/store" method="post">
        <input type="email" name="email" placeholder="Enter your email">
        <button type="submit">Notify Me</button>
    </form>
</body>
</html>

Now that we have a simple pre-launch page with a form to collect email addresses, we just need to create a route that will render this view.

index.php

php

<?php

require __DIR__ . '/vendor/autoload.php';

app()->get('/', function() {
    response()->json(['message' => 'Hello, World!']);
});

app()->view('/prelaunch', 'prelaunch');  

app()->run();

Here's what's happening behind the scenes:

app() is a helper function that gives you access to the Leaf app instance. You can use it anywhere in your app.
view() is a method for defining a route that renders a Blade view. The first argument is the URL path, and the second is the name of the view file to load.

Notice we did not have to configure Blade because Leaf does that for you. You can now navigate to http://localhost:5500/prelaunch to see your pre-launch page.

2 Handling the form submission

Now that we have a pre-launch page, we need to handle form submissions. Let’s create a new route to process the form and save the email to a database.

index.php

php

app()->view('/prelaunch', 'prelaunch');
app()->post('/store', function () { 
  // handle the email //
});

We used the post() method to ensure only POST requests reach this route. The second argument is a function where we'll handle the email. Leaf makes validation simple—we can call validate() on the request and define our validation rules. Let’s validate and store the email.

index.php

php

app()->post('/store', function () {
    if (!$data = request()->validate(['email' => 'email'])) { 
        // validation failed, redirect back with errors //
        return response() 
          ->withFlash('errors', request()->errors()) 
          ->redirect('/prelaunch'); 
    } 

    // save the email
});

That’s it for validation! But before we can save the email, we need to connect our database to the application. Let’s set that up next.

3 Setting up our database

We can set up our database by installing the database module and configuring our credentials. Just like we installed Blade earlier, we’ll install the database module the same way.

Leaf CLIComposer

bash

leaf install db

bash

composer require leafs/db

Now we just need to fill out our database information:

index.php

php

<?php

require __DIR__ . '/vendor/autoload.php';

db()->connect([ 
  'host' => '127.0.0.1', 
  'username' => 'root', 
  'password' => '', 
  'dbname' => 'Leaf', 
]); 

app()->get('/', function() {
    response()->json(['message' => 'Hello, World!']);
});

app()->view('/prelaunch', 'prelaunch');

app()->post('/store', function () {
    if (!$data = request()->validate(['email' => 'email'])) {
        // validation failed, redirect back with errors
        return response()
          ->withFlash('errors', request()->errors())
          ->redirect('/prelaunch');
    }

    // save the email
});

app()->run();

Creating your database

Unlike with Leaf MVC, Leaf as a micro-framework does not come with a database migration system. You will have to create your database manually. You can do this using a tool like phpMyAdmin, TablePlus or the command line.

sql

CREATE DATABASE Leaf;

Once you have filled out your database information, you can now save the email to the database.

4 Saving the email

We can now save the email to the database.

index.php

php

<?php

require __DIR__ . '/vendor/autoload.php';

db()->connect([
  'host' => '127.0.0.1',
  'username' => 'root',
  'password' => '',
  'dbname' => 'Leaf',
]);

app()->get('/', function() {
    response()->json(['message' => 'Hello, World!']);
});

app()->view('/prelaunch', 'prelaunch');

app()->post('/store', function () {
    if (!$data = request()->validate(['email' => 'email'])) {
        // validation failed, redirect back with errors
        return response()
          ->withFlash('errors', request()->errors())
          ->redirect('/prelaunch');
    }

    db()->insert('emails')->params($data)->execute(); 

    return response() 
      ->withFlash('success', 'You have been added to our list!') 
      ->redirect('/prelaunch'); 
});

app()->run();

You can use the withFlash() method to send a message to the next request. This is useful for sending messages to the user after a redirect. We can now test our app by navigating to the /prelaunch page and submitting an email.

5 Deploying your app

We have built a simple pre-launch page using Leaf. You can now deploy your app to a server using a service like Heroku, Fly.io a VPS like DigitalOcean, or even a shared hosting service like Sevalla.

Are you stuck? Leaf as a micro-framework is a great way to build simple applications and APIs quickly, but doesn't provide the structure you get with Leaf MVC. If you are stuck at any point, feel free to ask for help in the Leaf Discord server, or consider building an MVP using Leaf MVC if you prefer a more structured approach.

What to read next

Now that you have built a simple pre-launch page, the next step is to get you familiar with the basics of building a full-stack application with Leaf. So you can build and launch your next big idea fast.

Routing
Learn more about routing in Leaf MVC, dynamic routes, middleware and more.
Handling Requests
Learn how to process incoming requests, handle form submissions, and more.
Using Databases
Learn how to build queries, build relationships, and interact with your database programmatically.
Frontend
Learn about SSR, SPA, and how to use Leaf with your favorite frontend framework.

Leaf as a micro-framework ​

Getting started ​

Building your first app ​

1 Setting up our views ​

2 Handling the form submission ​

3 Setting up our database ​

4 Saving the email ​

5 Deploying your app ​

What to read next ​

Routing

Handling Requests

Using Databases

Frontend

Leaf as a micro-framework

Getting started

Building your first app

1 Setting up our views

2 Handling the form submission

3 Setting up our database

4 Saving the email

5 Deploying your app

What to read next