Solo Application

🧅

PSR-15 Pipeline

Global middleware run outermost first and are resolved from the container only when a request reaches them. Class names, middleware objects and callables can be mixed.

🧭

Built-in Routing

RoutingMiddleware matches the route, runs group and route middleware, and puts the handler, parameters, route name and attributes on the request.

⚡

Route Cache

One config option keeps the built router in a PHP file that OPcache holds in memory, so a request skips registering and compiling routes.

🚦

Routing Errors as Exceptions

404, 405 with Allow and 400 are thrown as RoutingException. Answer them with RoutingErrorMiddleware or render them in your own error middleware.

📦

Service Providers

Plain classes with a register() method fill the container. Use solophp/container or any container that implements WritableContainerInterface.

🎯

Flexible Handlers

Controller methods and invokable classes come from the container; closures and other callables are called as they are.

🔁

Workers and Tests

Application is itself a PSR-15 request handler. handle() returns the response without emitting it, for tests and worker runtimes.

🧩

Built on Standards

PSR-7, PSR-11, PSR-15 and PSR-17 interfaces, solophp/contracts for the container and the emitter, and solophp/router for routes.

Version 4.0.1

Solo Application 4.0.1 requires PHP 8.3 or later. It creates the RouteCollector, calls your routes.php and builds the router with Solo Router 4, keeps it in a route cache if you ask it to, and throws routing errors instead of answering them with empty responses. Upgrading from 3.x? Read the upgrade guide.

4.0.0, published on 17 October 2026, is an earlier state of this release that still takes the router from the container: install 4.0.1 or later.

Quick Example

php

<?php
// public/index.php

use App\Providers\HttpServiceProvider;
use Solo\Application\Application;
use Solo\Application\Config;
use Solo\Application\RoutingErrorMiddleware;
use Solo\Application\RoutingMiddleware;

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

$app = new Application(new Config(
    basePath: dirname(__DIR__),
    routesPath: dirname(__DIR__) . '/app/routes.php',
    providers: [HttpServiceProvider::class],
    middleware: [RoutingErrorMiddleware::class, RoutingMiddleware::class],
));

$app->run();

php

<?php
// app/routes.php

use App\Controller\UserController;
use Solo\Router\RouteCollector;

return function (RouteCollector $r): void {
    $r->get('/users/{id}', [UserController::class, 'show'])->name('users.show');
};

The controller comes from the container and gets the request, a new response and the route parameters:

php

<?php

namespace App\Controller;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

final class UserController
{
    public function show(ServerRequestInterface $request, ResponseInterface $response, array $params): ResponseInterface
    {
        $response->getBody()->write("User {$params['id']}");

        return $response;
    }
}

HttpServiceProvider registers the PSR-17 factory, the incoming request and the emitter: see the quick start.

bash

composer require "solophp/application:^4.0.1"

Requirements: PHP 8.3 or later, a PSR-7/PSR-17 implementation, a container and an HTTP emitter. See installation.

Solo ApplicationPSR-15 Application Kernel