diff --git a/app/CatchAllRouteServiceProvider.php b/app/CatchAllRouteServiceProvider.php
new file mode 100644
index 0000000000..fd9ab4292b
--- /dev/null
+++ b/app/CatchAllRouteServiceProvider.php
@@ -0,0 +1,81 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CultuurNet\UDB3\Silex;
+
+use CultuurNet\UDB3\Http\LegacyPathRewriter;
+use League\Route\Router;
+use Silex\Application;
+use Silex\ServiceProviderInterface;
+use Symfony\Bridge\PsrHttpMessage\Factory\DiactorosFactory;
+use Symfony\Bridge\PsrHttpMessage\Factory\HttpFoundationFactory;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+
+final class CatchAllRouteServiceProvider implements ServiceProviderInterface
+{
+    public function register(Application $app): void
+    {
+    }
+
+    public function boot(Application $app): void
+    {
+        $pathHasBeenRewrittenForSilex = false;
+        $originalRequest = null;
+
+        // NOTE: THIS CATCH-ALL ROUTE HAS TO BE REGISTERED INSIDE boot() SO THAT (DYNAMICALLY GENERATED) OPTIONS ROUTES
+        // FOR CORS GET REGISTERED FIRST BEFORE THIS ONE.
+        // Matches any path that does not match a registered route, and rewrites it using a set of predefined pattern
+        // replacements and sends an internal sub-request to try and match an existing route.
+        // This makes it possible to support old endpoint names without having to register controllers/request handlers
+        // twice.
+        // If the sub-request does not return a response either, it will be converted to a PSR request and dispatched on
+        // a new PSR router.
+        $app->match(
+            '/{path}',
+            function (Request $request, string $path) use ($app, &$pathHasBeenRewrittenForSilex, &$originalRequest) {
+                if (!$pathHasBeenRewrittenForSilex) {
+                    // If the path has not been rewritten before, rewrite it and dispatch the request again to the Silex
+                    // router.
+                    $rewrittenPath = (new LegacyPathRewriter())->rewritePath($path);
+                    $pathHasBeenRewrittenForSilex = true;
+                    $originalRequest = $request;
+
+                    // Create a new Request object with the rewritten path, because it's basically impossible to overwrite
+                    // the path of an existing Request object even with initialize() or duplicate(). Approach copied from
+                    // https://github.com/graze/silex-trailing-slash-handler/blob/1.x/src/TrailingSlashControllerProvider.php
+                    $rewrittenRequest = Request::create(
+                        $rewrittenPath,
+                        $request->getMethod(),
+                        [],
+                        $request->cookies->all(),
+                        $request->files->all(),
+                        $request->server->all(),
+                        $request->getContent()
+                    );
+                    $rewrittenRequest = $rewrittenRequest->duplicate(
+                        $request->query->all(),
+                        $request->request->all()
+                    );
+                    $rewrittenRequest->headers->replace($app['request']->headers->all());
+
+                    // Handle the request with the rewritten path.
+                    // If the Silex app still cannot match the new path to a route, this catch-all route will be matched
+                    // again and that time we will dispatch it to the new PSR router because
+                    // $pathHasBeenRewrittenForSilex will be set to true.
+                    return $app->handle($rewrittenRequest, HttpKernelInterface::SUB_REQUEST);
+                }
+
+                // If the request is still not matched with a route after it has been rewritten and dispatched on the
+                // Silex router a second time, convert it to a PSR request and dispatch it on the PSR router instead.
+                /** @var Router $psrRouter */
+                $psrRouter = $app[Router::class];
+                $psrRequest = (new DiactorosFactory())->createRequest($originalRequest);
+                $psrRequest = (new LegacyPathRewriter())->rewriteRequest($psrRequest);
+                $psrResponse = $psrRouter->handle($psrRequest);
+                return (new HttpFoundationFactory())->createResponse($psrResponse);
+            }
+        )->assert('path', '^.+$');
+    }
+}
diff --git a/app/Error/WebErrorHandlerProvider.php b/app/Error/WebErrorHandlerProvider.php
index 35b92084b2..72c7887561 100644
--- a/app/Error/WebErrorHandlerProvider.php
+++ b/app/Error/WebErrorHandlerProvider.php
@@ -16,6 +16,8 @@
 use CultuurNet\UDB3\Security\CommandAuthorizationException;
 use Error;
 use Exception;
+use League\Route\Http\Exception\MethodNotAllowedException;
+use League\Route\Http\Exception\NotFoundException;
 use Respect\Validation\Exceptions\GroupedValidationException;
 use Silex\Application;
 use Silex\ServiceProviderInterface;
@@ -89,6 +91,18 @@ private static function convertThrowableToApiProblem(Request $request, Throwable
                     )
                 );
 
+            case $e instanceof NotFoundException:
+                return ApiProblem::urlNotFound();
+
+            case $e instanceof MethodNotAllowedException:
+                $details = null;
+                $headers = $e->getHeaders();
+                $allowed = $headers['Allow'] ?? null;
+                if ($allowed !== null) {
+                    $details = 'Allowed: ' . $allowed;
+                }
+                return ApiProblem::methodNotAllowed($details);
+
             // Do a best effort to convert "not found" exceptions into an ApiProblem with preferably a detail mentioning
             // what kind of resource and with what id could not be found. Since the exceptions themselves do not contain
             // enough info to detect this, we need to get this info from the current request. However this is not
diff --git a/app/Http/PsrRouterServiceProvider.php b/app/Http/PsrRouterServiceProvider.php
new file mode 100644
index 0000000000..f1d61ac0c7
--- /dev/null
+++ b/app/Http/PsrRouterServiceProvider.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CultuurNet\UDB3\Silex\Http;
+
+use CultuurNet\UDB3\Http\CustomLeagueRouterStrategy;
+use CultuurNet\UDB3\Http\Offer\GetDetailRequestHandler;
+use League\Route\Router;
+use Silex\Application;
+use Silex\ServiceProviderInterface;
+
+final class PsrRouterServiceProvider implements ServiceProviderInterface
+{
+    public function register(Application $app): void
+    {
+        $app[Router::class] = $app::share(
+            function (Application $app) {
+                $router = new Router();
+                $router->setStrategy(new CustomLeagueRouterStrategy());
+
+                $router->get('/{offerType:events|places}/{offerId}/', [$app[GetDetailRequestHandler::class], 'handle']);
+
+                return $router;
+            }
+        );
+    }
+
+    public function boot(Application $app): void
+    {
+    }
+}
diff --git a/app/LegacyRoutesServiceProvider.php b/app/LegacyRoutesServiceProvider.php
deleted file mode 100644
index f645f6ca9d..0000000000
--- a/app/LegacyRoutesServiceProvider.php
+++ /dev/null
@@ -1,90 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace CultuurNet\UDB3\Silex;
-
-use CultuurNet\UDB3\Http\ApiProblem\ApiProblem;
-use CultuurNet\UDB3\Http\Response\ApiProblemJsonResponse;
-use Silex\Application;
-use Silex\ServiceProviderInterface;
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpKernel\HttpKernelInterface;
-
-final class LegacyRoutesServiceProvider implements ServiceProviderInterface
-{
-    public function register(Application $app): void
-    {
-    }
-
-    public function boot(Application $app): void
-    {
-        $pathHasBeenRewritten = false;
-
-        // NOTE: THIS CATCH-ALL ROUTE HAS TO BE REGISTERED INSIDE boot() SO THAT (DYNAMICALLY GENERATED) OPTIONS ROUTES
-        // FOR CORS GET REGISTERED FIRST BEFORE THIS ONE.
-        // Matches any path that does not match a registered route, and rewrites it using a set of predefined pattern
-        // replacements and sends an internal sub-request to try and match an existing route. If the sub-request does
-        // not return a response either an error response will be returned.
-        // This makes it possible to support old endpoint names without having to register controllers/request handlers
-        // twice. When we have a router with support for PSR-15 middlewares, we should refactor this URL rewriting to a
-        // PSR-15 middleware instead.
-        $app->match(
-            '/{path}',
-            function (Request $originalRequest, string $path) use ($app, &$pathHasBeenRewritten) {
-                if ($pathHasBeenRewritten) {
-                    return new ApiProblemJsonResponse(ApiProblem::urlNotFound());
-                }
-
-                $rewrites = [
-                    // Pluralize /event and /place
-                    '/^(event|place)($|\/.*)/' => '${1}s${2}',
-
-                    // Convert known legacy camelCase resource/collection names to kebab-case
-                    '/bookingAvailability/' => 'booking-availability',
-                    '/bookingInfo/' => 'booking-info',
-                    '/cardSystems/' => 'card-systems',
-                    '/contactPoint/' => 'contact-point',
-                    '/distributionKey/' => 'distribution-key',
-                    '/majorInfo/' => 'major-info',
-                    '/priceInfo/' => 'price-info',
-                    '/subEvents/' => 'sub-events',
-                    '/typicalAgeRange/' => 'typical-age-range',
-
-                    // Convert old "calsum" path to "calendar-summary"
-                    '/\/calsum/' => '/calendar-summary',
-
-                    // Convert old "news_articles" path to "news-articles"
-                    '/news_articles/' => 'news-articles',
-
-                    // Add trailing slash if missing
-                    '/^(.*)(?<!\/)$/' => '${1}/',
-                ];
-                $rewrittenPath = preg_replace(array_keys($rewrites), array_values($rewrites), $path);
-
-                $pathHasBeenRewritten = true;
-
-                // Create a new Request object with the rewritten path, because it's basically impossible to overwrite
-                // the path of an existing Request object even with initialize() or duplicate(). Approach copied from
-                // https://github.com/graze/silex-trailing-slash-handler/blob/1.x/src/TrailingSlashControllerProvider.php
-                $request = Request::create(
-                    $rewrittenPath,
-                    $originalRequest->getMethod(),
-                    [],
-                    $originalRequest->cookies->all(),
-                    $originalRequest->files->all(),
-                    $originalRequest->server->all(),
-                    $originalRequest->getContent()
-                );
-                $request = $request->duplicate(
-                    $originalRequest->query->all(),
-                    $originalRequest->request->all()
-                );
-                $request->headers->replace($app['request']->headers->all());
-
-                // Handle the request with the rewritten path.
-                return $app->handle($request, HttpKernelInterface::SUB_REQUEST);
-            }
-        )->assert('path', '^.+$');
-    }
-}
diff --git a/app/Offer/OfferControllerProvider.php b/app/Offer/OfferControllerProvider.php
index a04dda0ed1..bb4d9c1078 100644
--- a/app/Offer/OfferControllerProvider.php
+++ b/app/Offer/OfferControllerProvider.php
@@ -34,7 +34,6 @@ public function connect(Application $app): ControllerCollection
         /** @var ControllerCollection $controllers */
         $controllers = $app['controllers_factory'];
 
-        $controllers->get('/{offerType}/{offerId}/', GetDetailRequestHandler::class);
         $controllers->delete('/{offerType}/{offerId}/', DeleteRequestHandler::class);
 
         $controllers->put('/{offerType}/{offerId}/name/{language}/', UpdateTitleRequestHandler::class);
diff --git a/composer.json b/composer.json
index b95c9d27f1..17118fc622 100644
--- a/composer.json
+++ b/composer.json
@@ -46,6 +46,7 @@
     "league/flysystem": "^2.2.3",
     "league/flysystem-aws-s3-v3": "^2.1",
     "league/period": "^3.3",
+    "league/route": "^5.1",
     "league/uri": "^6.3",
     "league/uri-components": "^2.4",
     "marvin_b8/psr-7-service-provider": "^1.0",
diff --git a/composer.lock b/composer.lock
index 8287bc6b92..94a2da85e0 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "3f99b2736ddcaab57c3a49c7cb561d73",
+    "content-hash": "10e1021e42625df8920dc2562009b76b",
     "packages": [
         {
             "name": "auth0/auth0-php",
@@ -2681,6 +2681,95 @@
             ],
             "time": "2017-11-17T11:28:33+00:00"
         },
+        {
+            "name": "league/route",
+            "version": "5.1.2",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/thephpleague/route.git",
+                "reference": "adf9b961dc5ffdbcffb2b8d7963c7978f2794c92"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/thephpleague/route/zipball/adf9b961dc5ffdbcffb2b8d7963c7978f2794c92",
+                "reference": "adf9b961dc5ffdbcffb2b8d7963c7978f2794c92",
+                "shasum": ""
+            },
+            "require": {
+                "nikic/fast-route": "^1.3",
+                "opis/closure": "^3.5.5",
+                "php": "^7.2 || ^8.0",
+                "psr/container": "^1.0|^2.0",
+                "psr/http-factory": "^1.0",
+                "psr/http-message": "^1.0.1",
+                "psr/http-server-handler": "^1.0.1",
+                "psr/http-server-middleware": "^1.0.1",
+                "psr/simple-cache": "^1.0"
+            },
+            "replace": {
+                "orno/http": "~1.0",
+                "orno/route": "~1.0"
+            },
+            "require-dev": {
+                "laminas/laminas-diactoros": "^2.3",
+                "phpstan/phpstan": "^0.12",
+                "phpstan/phpstan-phpunit": "^0.12",
+                "phpunit/phpunit": "^8.5",
+                "roave/security-advisories": "dev-master",
+                "scrutinizer/ocular": "^1.8",
+                "squizlabs/php_codesniffer": "^3.5"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "5.x-dev",
+                    "dev-5.x": "5.x-dev",
+                    "dev-4.x": "4.x-dev",
+                    "dev-3.x": "3.x-dev",
+                    "dev-2.x": "2.x-dev",
+                    "dev-1.x": "1.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "League\\Route\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Phil Bennett",
+                    "email": "philipobenito@gmail.com",
+                    "role": "Developer"
+                }
+            ],
+            "description": "Fast routing and dispatch component including PSR-15 middleware, built on top of FastRoute.",
+            "homepage": "https://github.com/thephpleague/route",
+            "keywords": [
+                "dispatcher",
+                "league",
+                "psr-15",
+                "psr-7",
+                "psr15",
+                "psr7",
+                "route",
+                "router"
+            ],
+            "support": {
+                "issues": "https://github.com/thephpleague/route/issues",
+                "source": "https://github.com/thephpleague/route/tree/5.1.2"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/philipobenito",
+                    "type": "github"
+                }
+            ],
+            "time": "2021-07-30T08:33:09+00:00"
+        },
         {
             "name": "league/uri",
             "version": "6.5.0",
@@ -3549,6 +3638,56 @@
             ],
             "time": "2019-10-14T05:51:36+00:00"
         },
+        {
+            "name": "nikic/fast-route",
+            "version": "v1.3.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/nikic/FastRoute.git",
+                "reference": "181d480e08d9476e61381e04a71b34dc0432e812"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/nikic/FastRoute/zipball/181d480e08d9476e61381e04a71b34dc0432e812",
+                "reference": "181d480e08d9476e61381e04a71b34dc0432e812",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^4.8.35|~5.7"
+            },
+            "type": "library",
+            "autoload": {
+                "files": [
+                    "src/functions.php"
+                ],
+                "psr-4": {
+                    "FastRoute\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Nikita Popov",
+                    "email": "nikic@php.net"
+                }
+            ],
+            "description": "Fast request router for PHP",
+            "keywords": [
+                "router",
+                "routing"
+            ],
+            "support": {
+                "issues": "https://github.com/nikic/FastRoute/issues",
+                "source": "https://github.com/nikic/FastRoute/tree/master"
+            },
+            "time": "2018-02-13T20:26:39+00:00"
+        },
         {
             "name": "ocramius/proxy-manager",
             "version": "2.1.1",
@@ -3618,6 +3757,71 @@
             ],
             "time": "2017-05-04T11:12:50+00:00"
         },
+        {
+            "name": "opis/closure",
+            "version": "3.6.3",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/opis/closure.git",
+                "reference": "3d81e4309d2a927abbe66df935f4bb60082805ad"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/opis/closure/zipball/3d81e4309d2a927abbe66df935f4bb60082805ad",
+                "reference": "3d81e4309d2a927abbe66df935f4bb60082805ad",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.4 || ^7.0 || ^8.0"
+            },
+            "require-dev": {
+                "jeremeamia/superclosure": "^2.0",
+                "phpunit/phpunit": "^4.0 || ^5.0 || ^6.0 || ^7.0 || ^8.0 || ^9.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "3.6.x-dev"
+                }
+            },
+            "autoload": {
+                "files": [
+                    "functions.php"
+                ],
+                "psr-4": {
+                    "Opis\\Closure\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Marius Sarca",
+                    "email": "marius.sarca@gmail.com"
+                },
+                {
+                    "name": "Sorin Sarca",
+                    "email": "sarca_sorin@hotmail.com"
+                }
+            ],
+            "description": "A library that can be used to serialize closures (anonymous functions) and arbitrary objects.",
+            "homepage": "https://opis.io/closure",
+            "keywords": [
+                "anonymous functions",
+                "closure",
+                "function",
+                "serializable",
+                "serialization",
+                "serialize"
+            ],
+            "support": {
+                "issues": "https://github.com/opis/closure/issues",
+                "source": "https://github.com/opis/closure/tree/3.6.3"
+            },
+            "time": "2022-01-27T09:35:39+00:00"
+        },
         {
             "name": "opis/json-schema",
             "version": "2.1.0",
diff --git a/src/Http/ApiProblem/ApiProblem.php b/src/Http/ApiProblem/ApiProblem.php
index beff2eb75b..d62ad842ca 100644
--- a/src/Http/ApiProblem/ApiProblem.php
+++ b/src/Http/ApiProblem/ApiProblem.php
@@ -222,6 +222,16 @@ public static function notAcceptable(string $detail = null): self
         );
     }
 
+    public static function methodNotAllowed(string $detail = null): self
+    {
+        return self::create(
+            'https://api.publiq.be/probs/method/not-allowed',
+            'Method not allowed',
+            405,
+            $detail
+        );
+    }
+
     public static function urlNotFound(string $detail = null): self
     {
         return self::create(
diff --git a/src/Http/CustomLeagueRouterStrategy.php b/src/Http/CustomLeagueRouterStrategy.php
new file mode 100644
index 0000000000..ebaf1c3f3c
--- /dev/null
+++ b/src/Http/CustomLeagueRouterStrategy.php
@@ -0,0 +1,96 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CultuurNet\UDB3\Http;
+
+use CultuurNet\UDB3\Http\Response\NoContentResponse;
+use League\Route\ContainerAwareInterface;
+use League\Route\ContainerAwareTrait;
+use League\Route\Http\Exception\MethodNotAllowedException;
+use League\Route\Http\Exception\NotFoundException;
+use League\Route\Route;
+use League\Route\Strategy\AbstractStrategy;
+use League\Route\Strategy\OptionsHandlerInterface;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Throwable;
+
+/**
+ * Copied from League\Route\Strategy\ApplicationStrategy as a base to customize, as suggested by the League Router docs.
+ * Note that we did not use League\Route\Strategy\JsonStrategy because it was a bit too opinionated about for example
+ * error responses.
+ *
+ * Expanded to implement OptionsHandlerInterface, to support OPTIONS requests for every registered route without having
+ * to register a catch-all route which resulted in "Method Not Allowed" errors instead of "Not Found" errors if an
+ * unknown URL was requested.
+ */
+final class CustomLeagueRouterStrategy extends AbstractStrategy implements
+    ContainerAwareInterface,
+    OptionsHandlerInterface
+{
+    use ContainerAwareTrait;
+
+    public function getOptionsCallable(array $methods): callable
+    {
+        return static function (): ResponseInterface {
+            // Just return a 204 No Content for every OPTIONS request.
+            // Actual CORS headers are added via a middleware, so they are also added to other requests.
+            return new NoContentResponse();
+        };
+    }
+
+    public function getMethodNotAllowedDecorator(MethodNotAllowedException $exception): MiddlewareInterface
+    {
+        return $this->throwThrowableMiddleware($exception);
+    }
+
+    public function getNotFoundDecorator(NotFoundException $exception): MiddlewareInterface
+    {
+        return $this->throwThrowableMiddleware($exception);
+    }
+
+    public function getThrowableHandler(): MiddlewareInterface
+    {
+        return new class() implements MiddlewareInterface {
+            public function process(
+                ServerRequestInterface $request,
+                RequestHandlerInterface $handler
+            ): ResponseInterface {
+                try {
+                    return $handler->handle($request);
+                } catch (Throwable $e) {
+                    throw $e;
+                }
+            }
+        };
+    }
+
+    public function invokeRouteCallable(Route $route, ServerRequestInterface $request): ResponseInterface
+    {
+        $controller = $route->getCallable($this->getContainer());
+        $response = $controller($request, $route->getVars());
+        return $this->decorateResponse($response);
+    }
+
+    protected function throwThrowableMiddleware(Throwable $error): MiddlewareInterface
+    {
+        return new class($error) implements MiddlewareInterface {
+            protected $error;
+
+            public function __construct(Throwable $error)
+            {
+                $this->error = $error;
+            }
+
+            public function process(
+                ServerRequestInterface $request,
+                RequestHandlerInterface $handler
+            ): ResponseInterface {
+                throw $this->error;
+            }
+        };
+    }
+}
diff --git a/src/Http/LegacyPathRewriter.php b/src/Http/LegacyPathRewriter.php
new file mode 100644
index 0000000000..dbe1c3941f
--- /dev/null
+++ b/src/Http/LegacyPathRewriter.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CultuurNet\UDB3\Http;
+
+use Psr\Http\Message\ServerRequestInterface;
+
+final class LegacyPathRewriter
+{
+    private const REWRITES = [
+        // Pluralize /event and /place
+        '/^(\/)?(event|place)($|\/.*)/' => '${1}${2}s${3}',
+
+        // Convert known legacy camelCase resource/collection names to kebab-case
+        '/bookingAvailability/' => 'booking-availability',
+        '/bookingInfo/' => 'booking-info',
+        '/cardSystems/' => 'card-systems',
+        '/contactPoint/' => 'contact-point',
+        '/distributionKey/' => 'distribution-key',
+        '/majorInfo/' => 'major-info',
+        '/priceInfo/' => 'price-info',
+        '/subEvents/' => 'sub-events',
+        '/typicalAgeRange/' => 'typical-age-range',
+
+        // Convert old "calsum" path to "calendar-summary"
+        '/\/calsum/' => '/calendar-summary',
+
+        // Convert old "news_articles" path to "news-articles"
+        '/news_articles/' => 'news-articles',
+
+        // Add trailing slash if missing
+        '/^(.*)(?<!\/)$/' => '${1}/',
+    ];
+
+    public function rewritePath(string $path): string
+    {
+        return preg_replace(array_keys(self::REWRITES), array_values(self::REWRITES), $path);
+    }
+
+    public function rewriteRequest(ServerRequestInterface $request): ServerRequestInterface
+    {
+        $uri = $request->getUri();
+        $path = $uri->getPath();
+        $rewrittenPath = $this->rewritePath($path);
+        $rewrittenUri = $uri->withPath($rewrittenPath);
+        return $request->withUri($rewrittenUri);
+    }
+}
diff --git a/src/Http/Request/RouteParameters.php b/src/Http/Request/RouteParameters.php
index b10725bae9..e160bcf1c0 100644
--- a/src/Http/Request/RouteParameters.php
+++ b/src/Http/Request/RouteParameters.php
@@ -14,25 +14,31 @@
 
 final class RouteParameters
 {
-    private array $routeParameters;
+    private array $attributes;
 
     public function __construct(ServerRequestInterface $request)
     {
-        $attributes = $request->getAttributes();
-        $this->routeParameters = $attributes['_route_params'] ?? [];
+        $this->attributes = $request->getAttributes();
     }
 
     public function get(string $parameterName): string
     {
-        if (!isset($this->routeParameters[$parameterName])) {
-            throw new RuntimeException('Route parameter ' . $parameterName . ' not found in given ServerRequestInterface!');
+        // The League router puts the parameters directly in the request attributes.
+        if (isset($this->attributes[$parameterName])) {
+            return (string) $this->attributes[$parameterName];
         }
-        return (string) $this->routeParameters[$parameterName];
+        // The Silex router puts the parameters in a "_route_params" nested array.
+        if (isset($this->attributes['_route_params'][$parameterName])) {
+            return (string) $this->attributes['_route_params'][$parameterName];
+        }
+        throw new RuntimeException('Route parameter ' . $parameterName . ' not found in given ServerRequestInterface!');
     }
 
     public function has(string $parameterName): bool
     {
-        return isset($this->routeParameters[$parameterName]);
+        // The League router puts the parameters directly in the request attributes.
+        // The Silex router puts the parameters in a "_route_params" nested array.
+        return isset($this->attributes[$parameterName]) || isset($this->attributes['_route_params'][$parameterName]);
     }
 
     public function getEventId(): string
diff --git a/tests/Http/LegacyPathRewriterTest.php b/tests/Http/LegacyPathRewriterTest.php
new file mode 100644
index 0000000000..f9a50ddea5
--- /dev/null
+++ b/tests/Http/LegacyPathRewriterTest.php
@@ -0,0 +1,136 @@
+<?php
+
+declare(strict_types=1);
+
+namespace CultuurNet\UDB3\Http;
+
+use PHPUnit\Framework\TestCase;
+
+class LegacyPathRewriterTest extends TestCase
+{
+    /**
+     * @test
+     * @dataProvider rewritesDataProvider
+     */
+    public function it_rewrites_legacy_paths_and_leaves_others_as_is(
+        string $originalPath,
+        string $expectedRewrite
+    ): void {
+        $actualRewrite = (new LegacyPathRewriter())->rewritePath($originalPath);
+        $this->assertEquals($expectedRewrite, $actualRewrite);
+    }
+
+    public function rewritesDataProvider(): array
+    {
+        return [
+            'event_detail_singular_to_pluralized_and_trailing_slash' => [
+                'original' => '/event/ccb8f44b-d316-41f0-aeec-2b4149be6cd3',
+                'rewrite' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'place_detail_singular_to_pluralized_and_trailing_slash' => [
+                'original' => '/place/ccb8f44b-d316-41f0-aeec-2b4149be6cd3',
+                'rewrite' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'event_detail_untouched' => [
+                'original' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+                'rewrite' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'place_detail_untouched' => [
+                'original' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+                'rewrite' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'event_detail_without_prefixed_slash_singular_to_pluralized_and_trailing_slash' => [
+                'original' => 'event/ccb8f44b-d316-41f0-aeec-2b4149be6cd3',
+                'rewrite' => 'events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'place_detail_without_prefixed_slash_singular_to_pluralized_and_trailing_slash' => [
+                'original' => 'place/ccb8f44b-d316-41f0-aeec-2b4149be6cd3',
+                'rewrite' => 'places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'event_detail_without_prefixed_slash_untouched' => [
+                'original' => 'events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+                'rewrite' => 'events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'place_detail_without_prefixed_slash_untouched' => [
+                'original' => 'places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+                'rewrite' => 'places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/',
+            ],
+            'event_update_name_singular_to_pluralized_and_trailing_slash' => [
+                'original' => '/event/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl',
+                'rewrite' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl/',
+            ],
+            'place_update_name_singular_to_pluralized_and_trailing_slash' => [
+                'original' => '/place/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl',
+                'rewrite' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl/',
+            ],
+            'event_update_name_untouched' => [
+                'original' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl/',
+                'rewrite' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl/',
+            ],
+            'place_update_name_untouched' => [
+                'original' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl/',
+                'rewrite' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/name/nl/',
+            ],
+            'event_singular_calsum_to_pluralized_calendar_summary_and_trailing_slash' => [
+                'original' => '/event/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calsum',
+                'rewrite' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calendar-summary/',
+            ],
+            'place_singular_calsum_to_pluralized_calendar_summary_and_trailing_slash' => [
+                'original' => '/place/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calsum',
+                'rewrite' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calendar-summary/',
+            ],
+            'event_calsum_to_calendar_summary_and_trailing_slash' => [
+                'original' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calsum',
+                'rewrite' => '/events/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calendar-summary/',
+            ],
+            'place_calsum_to_calendar_summary_and_trailing_slash' => [
+                'original' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calsum',
+                'rewrite' => '/places/ccb8f44b-d316-41f0-aeec-2b4149be6cd3/calendar-summary/',
+            ],
+            'news_articles_with_underscore_to_hyphen_and_trailing_slash' => [
+                'original' => '/news_articles',
+                'rewrite' => '/news-articles/',
+            ],
+            'news_articles_detail_with_underscore_to_kebab_case_and_trailing_slash' => [
+                'original' => '/news_articles/8a5fcfae-e698-437a-87a5-32cd4ac61076',
+                'rewrite' => '/news-articles/8a5fcfae-e698-437a-87a5-32cd4ac61076/',
+            ],
+            'event_update_booking_availability_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/bookingAvailability',
+                'rewrite' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/booking-availability/',
+            ],
+            'event_update_booking_info_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/bookingInfo',
+                'rewrite' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/booking-info/',
+            ],
+            'event_update_contact_point_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/contactPoint',
+                'rewrite' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/contact-point/',
+            ],
+            'event_update_major_info_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/majorInfo',
+                'rewrite' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/major-info/',
+            ],
+            'event_update_price_info_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/priceInfo',
+                'rewrite' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/price-info/',
+            ],
+            'event_update_sub_events_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/subEvents',
+                'rewrite' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/sub-events/',
+            ],
+            'event_update_typical_age_range_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/typicalAgeRange',
+                'rewrite' => '/events/8a5fcfae-e698-437a-87a5-32cd4ac61076/typical-age-range/',
+            ],
+            'event_uitpas_card_systems_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/uitpas/events/08a70475-4ffe-44b9-b0b9-256c82e7d747/cardSystems',
+                'rewrite' => '/uitpas/events/08a70475-4ffe-44b9-b0b9-256c82e7d747/card-systems/',
+            ],
+            'event_uitpas_distribution_keys_camel_case_to_kebab_case_and_trailing_slash' => [
+                'original' => '/uitpas/events/08a70475-4ffe-44b9-b0b9-256c82e7d747/cardSystems/1/distributionKey',
+                'rewrite' => '/uitpas/events/08a70475-4ffe-44b9-b0b9-256c82e7d747/card-systems/1/distribution-key/',
+            ],
+        ];
+    }
+}
diff --git a/tests/Http/Request/Psr7RequestBuilder.php b/tests/Http/Request/Psr7RequestBuilder.php
index 3abccdf474..5cb0d976c9 100644
--- a/tests/Http/Request/Psr7RequestBuilder.php
+++ b/tests/Http/Request/Psr7RequestBuilder.php
@@ -99,19 +99,22 @@ public function withRouteParameter(string $parameterName, string $parameterValue
 
     public function build(string $method): ServerRequestInterface
     {
-        return (
-            new Request(
-                $method,
-                $this->uri ?? self::getUriFactory()->createUri(),
-                $this->headers ?? new Headers(),
-                [],
-                [],
-                $this->body ?? self::getStreamFactory()->createStream(),
-                $this->files,
-            )
-        )
-            ->withAttribute('_route_params', $this->routeParameters)
-            ->withParsedBody($this->parsedBody);
+        $request = new Request(
+            $method,
+            $this->uri ?? self::getUriFactory()->createUri(),
+            $this->headers ?? new Headers(),
+            [],
+            [],
+            $this->body ?? self::getStreamFactory()->createStream(),
+            $this->files,
+        );
+
+        foreach ($this->routeParameters as $routeParameter => $value) {
+            $request = $request->withAttribute($routeParameter, $value);
+        }
+
+        $request = $request->withParsedBody($this->parsedBody);
+        return $request;
     }
 
     private static function getUriFactory(): UriFactory
diff --git a/tests/Http/Request/RouteParametersTest.php b/tests/Http/Request/RouteParametersTest.php
index cc4635a24c..b83a6c5f36 100644
--- a/tests/Http/Request/RouteParametersTest.php
+++ b/tests/Http/Request/RouteParametersTest.php
@@ -18,10 +18,10 @@ class RouteParametersTest extends TestCase
     /**
      * @test
      */
-    public function it_should_return_an_existing_route_parameter_from_the_request_as_string(): void
+    public function it_should_return_an_existing_route_parameter_from_the_psr_request_as_string(): void
     {
         $request = (new Psr7RequestBuilder())->build('PUT');
-        $request = $request->withAttribute('_route_params', ['foo' => 'bar']);
+        $request = $request->withAttribute('foo', 'bar');
         $routeParameters = new RouteParameters($request);
 
         $this->assertEquals('bar', $routeParameters->get('foo'));
@@ -30,14 +30,13 @@ public function it_should_return_an_existing_route_parameter_from_the_request_as
     /**
      * @test
      */
-    public function it_should_throw_a_runtime_exception_if_a_parameter_is_requested_that_is_not_set(): void
+    public function it_should_return_an_existing_route_parameter_from_the_silex_request_as_string(): void
     {
         $request = (new Psr7RequestBuilder())->build('PUT');
-        $request = $request->withAttribute('_route_params', []);
+        $request = $request->withAttribute('_route_params', ['foo' => 'bar']);
         $routeParameters = new RouteParameters($request);
 
-        $this->expectException(RuntimeException::class);
-        $routeParameters->get('foo');
+        $this->assertEquals('bar', $routeParameters->get('foo'));
     }
 
     /**
diff --git a/web/index.php b/web/index.php
index e176777dcc..039a25c4d7 100644
--- a/web/index.php
+++ b/web/index.php
@@ -12,13 +12,14 @@
 use CultuurNet\UDB3\Role\ValueObjects\Permission;
 use CultuurNet\UDB3\Silex\ApiName;
 use CultuurNet\UDB3\Silex\Curators\CuratorsControllerProvider;
+use CultuurNet\UDB3\Silex\Http\PsrRouterServiceProvider;
 use CultuurNet\UDB3\Silex\Udb3ControllerCollection;
 use CultuurNet\UDB3\Silex\Error\WebErrorHandlerProvider;
 use CultuurNet\UDB3\Silex\Error\ErrorLogger;
 use CultuurNet\UDB3\Silex\Event\EventControllerProvider;
 use CultuurNet\UDB3\Silex\Http\RequestHandlerControllerServiceProvider;
 use CultuurNet\UDB3\Silex\Import\ImportControllerProvider;
-use CultuurNet\UDB3\Silex\LegacyRoutesServiceProvider;
+use CultuurNet\UDB3\Silex\CatchAllRouteServiceProvider;
 use CultuurNet\UDB3\Silex\Offer\DeprecatedOfferControllerProvider;
 use CultuurNet\UDB3\Silex\Offer\OfferControllerProvider;
 use CultuurNet\UDB3\Silex\Place\PlaceControllerProvider;
@@ -57,6 +58,13 @@
  */
 $app->register(new RequestHandlerControllerServiceProvider());
 
+/**
+ * Register a PSR-7 / PSR-15 compatible router.
+ * Will be used in CatchAllRouteServiceProvider to route unmatched requests from Silex to the PSR router, until we can
+ * completely by-pass the Silex router.
+ */
+$app->register(new PsrRouterServiceProvider());
+
 /**
  * Firewall configuration.
  *
@@ -247,11 +255,15 @@ function () {
 // Match with any OPTIONS request with any URL and return a 204 No Content. Actual CORS headers will be added by an
 // ->after() middleware, which adds CORS headers to every request (so non-preflighted requests like simple GETs also get
 // the needed CORS headers).
+// Note that the new PSR router in PsrRouterServiceProvider already supports OPTIONS requests for all routes registered
+// in the new router, so this can be removed completely once all route definitions and handlers are moved to the new
+// router.
 $app->options('/{path}', fn () => new NoContentResponse())->assert('path', '^.+$');
 
 // Add CORS headers to every request. We explicitly allow everything, because we don't use cookies and our API is not on
 // an internal network, so CORS requests are never a security issue in our case. This greatly reduces the risk of CORS
 // bugs in our frontend and other integrations.
+// @todo III-4235 Move to Middleware in new PSR router when all routes are registered on the new router.
 $app->after(
     function (Request $request, Response $response) {
         // Allow any known method regardless of the URL.
@@ -272,7 +284,7 @@ function (Request $request, Response $response) {
     }
 );
 
-$app->register(new LegacyRoutesServiceProvider());
+$app->register(new CatchAllRouteServiceProvider());
 
 JsonSchemaLocator::setSchemaDirectory(__DIR__ . '/../vendor/publiq/udb3-json-schemas');