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Run your application

Write swerve.php and run your application with vendor/bin/swerve.

Swerve serves a PHP file that returns a Swerve\RequestHandler wrapping a closure. By default it is swerve.php in the current directory, and the closure runs once for each HTTP exchange, with a Swerve\ClientRequest to read and respond to:

<?php // swerve.php

return new Swerve\RequestHandler(function (Swerve\ClientRequest $request) {
    parse_str((string) parse_url($request->getTarget(), PHP_URL_QUERY), $query);

    $request->sendResponseHeaders(200, ['content-type' => 'text/plain']);
    $request->write('Hello, ' . ($query['name'] ?? 'World') . "\n");
});

> vendor/bin/swerve
2026-10-19 15:48:53.19   swerve 0.1.0 serving ./swerve.php on http://127.0.0.1:8080 with 8 workers
2026-10-19 15:48:54.04 4 GET /?name=Frode 200 0.3ms

Every log line has the time, the worker's slot number (blank for the master process), and the message. A request line has its status and how long the handler took; anything else worth knowing — a worker that crashed, a reload — is logged the same way. Ctrl+C stops swerve, letting requests already in flight finish.

The file is loaded once in each worker process, when the worker starts: code outside the closure (building the application, reading configuration, connecting to a database) runs once per worker, not once per request, and stays in memory for every request the worker goes on to serve.

Swerve\Swerve::log() is swerve's own log as a PSR-3 LoggerInterface: give it to your application, or call it directly, and your lines land in the same place as the request lines above, with the time and the worker's slot:

Swerve\Swerve::log()->warning('Payment {id} declined', ['id' => 42]);

2026-10-19 15:55:35.79 0 warning   Payment 42 declined

Options you will want first#

vendor/bin/swerve --http=:8080            # listen on every interface, not only 127.0.0.1
vendor/bin/swerve --public=public         # serve public/ (CSS, JavaScript, images) in front of swerve.php
vendor/bin/swerve -w 4                    # 4 workers, instead of one per CPU core

• --http=<address> takes a bare port (8080, this machine only), :8080 (every interface), a host and port, or unix:/path for a Unix domain socket. Repeat it to listen on several addresses.
• --public=<dir> serves the files in that directory and passes every other request to swerve.php: /css/site.css is public/css/site.css, / is public/index.html. This is deliberately small (no directory listing, PHP files are never served from it); for a lot of static content, put nginx or a CDN in front of swerve instead.
• -w, --workers=<n> sets the number of worker processes; auto (the default) is one per CPU core. Each worker holds its own copy of the application in memory.

vendor/bin/swerve --help lists every option; the dev server covers --watch, for development.

Next: Deploy.