diff --git a/app/Services/Packages/PackageSearchService.php b/app/Services/Packages/PackageSearchService.php
index b8a7aee..27b06b8 100644
--- a/app/Services/Packages/PackageSearchService.php
+++ b/app/Services/Packages/PackageSearchService.php
@@ -4,8 +4,10 @@
 namespace App\Services\Packages;
 
 use App\Models\Package;
+use App\Models\PackageRelease;
 use App\Values\Packages\PackageSearchRequest;
-use Illuminate\Contracts\Pagination\LengthAwarePaginator;
+use Composer\Semver\Semver;
+use Illuminate\Pagination\LengthAwarePaginator;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Support\Facades\DB;
 
@@ -35,7 +37,10 @@ public function search(PackageSearchRequest $request): LengthAwarePaginator
 
             $this->applyRequiresFilter($query, $request);
 
-            return $query->paginate(perPage: $request->per_page, page: $request->page);
+            return $this->filterPaginatedReleases(
+                $query->paginate(perPage: $request->per_page, page: $request->page),
+                $request,
+            );
         }
 
         // Try full-text search first
@@ -76,7 +81,10 @@ private function fullTextSearch(PackageSearchRequest $request): LengthAwarePagin
 
         $this->applyRequiresFilter($query, $request);
 
-        return $query->paginate(perPage: $request->per_page, page: $request->page);
+        return $this->filterPaginatedReleases(
+            $query->paginate(perPage: $request->per_page, page: $request->page),
+            $request,
+        );
     }
 
     /**
@@ -95,14 +103,21 @@ private function trigramSearch(PackageSearchRequest $request): LengthAwarePagina
 
         $this->applyRequiresFilter($query, $request);
 
-        return $query->paginate(perPage: $request->per_page, page: $request->page);
+        return $this->filterPaginatedReleases(
+            $query->paginate(perPage: $request->per_page, page: $request->page),
+            $request,
+        );
     }
 
     /**
      * Filter packages to those having at least one release compatible with the given requirements.
      *
-     * Compares dotted version strings as integer arrays, e.g. ?requires[typo3]=12.4 finds
-     * packages with a release requiring typo3 <= 12.4. Multiple requirements are ANDed together.
+     * Uses Composer\Semver to evaluate version constraints stored in the requires JSONB field,
+     * supporting ranges like ">=11.5.19 <=12.9.99", caret (^12.4), tilde (~12.4), etc.
+     *
+     * Optimization: instead of loading all releases into PHP, we first collect the distinct
+     * constraint strings per key (typically only 20-50 unique values), run Semver::satisfies()
+     * on those, then use SQL to find package IDs whose releases match the valid constraints.
      *
      * @param Builder<Package> $query
      */
@@ -112,17 +127,89 @@ private function applyRequiresFilter(Builder $query, PackageSearchRequest $reque
             return;
         }
 
-        $query->whereExists(function ($sub) use ($request) {
-            $sub->select(DB::raw(1))
-                ->from('package_releases')
-                ->whereColumn('package_releases.package_id', 'packages.id');
-
-            foreach ($request->requires as $key => $version) {
-                $sub->whereRaw(
-                    "package_releases.requires->>? IS NOT NULL AND string_to_array(package_releases.requires->>?, '.')::int[] <= string_to_array(?, '.')::int[]",
-                    [$key, $key, $version],
-                );
+        // Build a subquery that finds package IDs with at least one release matching all constraints.
+        // For each required key, we find the distinct constraint values, filter with Semver in PHP,
+        // then add a SQL condition for only the valid constraints.
+        $releaseQuery = DB::table('package_releases')
+            ->select('package_releases.package_id')
+            ->join('packages', 'packages.id', '=', 'package_releases.package_id')
+            ->where('packages.type', $request->type);
+
+        foreach ($request->requires as $key => $version) {
+            // Get distinct constraint strings for this key (e.g. ">=11.5.0 <=12.99.99", "^12.4")
+            $distinctConstraints = DB::table('package_releases')
+                ->join('packages', 'packages.id', '=', 'package_releases.package_id')
+                ->where('packages.type', $request->type)
+                ->whereRaw('jsonb_exists(package_releases.requires, ?)', [$key])
+                ->selectRaw('DISTINCT package_releases.requires->>? as constraint_value', [$key])
+                ->pluck('constraint_value');
+
+            // Filter to constraints that the provided version satisfies
+            $validConstraints = $distinctConstraints
+                ->filter(fn (string $constraint) => Semver::satisfies($version, $constraint))
+                ->values()
+                ->all();
+
+            if (empty($validConstraints)) {
+                // No valid constraints found — no packages can match
+                $query->whereRaw('1 = 0');
+
+                return;
             }
+
+            $releaseQuery->whereRaw(
+                'package_releases.requires->>? IN (' . implode(',', array_fill(0, count($validConstraints), '?')) . ')',
+                [$key, ...$validConstraints],
+            );
+        }
+
+        $matchingIds = $releaseQuery->distinct()->pluck('package_id')->all();
+
+        $query->whereIn('packages.id', $matchingIds);
+    }
+
+    /**
+     * Post-filter eager-loaded releases on paginated results using Composer\Semver.
+     *
+     * @param LengthAwarePaginator<int, Package> $results
+     * @return LengthAwarePaginator<int, Package>
+     */
+    private function filterPaginatedReleases(LengthAwarePaginator $results, PackageSearchRequest $request): LengthAwarePaginator
+    {
+        if (empty($request->requires)) {
+            return $results;
+        }
+
+        $results->getCollection()->each(function (Package $package) use ($request) {
+            $package->setRelation(
+                'releases',
+                $package->releases
+                    ->filter(fn (PackageRelease $release) => $this->releaseSatisfies($release, $request->requires))
+                    ->values(),
+            );
         });
+
+        return $results;
+    }
+
+    /**
+     * Check if a release satisfies all version requirements using Composer\Semver.
+     *
+     * @param array<string, string> $requires Key-value pairs of dependency name to user-provided version
+     */
+    private function releaseSatisfies(PackageRelease $release, array $requires): bool
+    {
+        foreach ($requires as $key => $version) {
+            $constraint = $release->requires[$key] ?? null;
+            if ($constraint === null) {
+                return false;
+            }
+
+            if (! Semver::satisfies($version, $constraint)) {
+                return false;
+            }
+        }
+
+        return true;
     }
 }
diff --git a/composer.json b/composer.json
index a7f3dd8..ef6e061 100644
--- a/composer.json
+++ b/composer.json
@@ -9,6 +9,7 @@
         "ext-intl": "*",
         "ext-mbstring": "*",
         "beacon-hq/bag": "^2.6.2",
+        "composer/semver": "^3.4",
         "crell/fp": "^1.0",
         "crell/serde": "^1.5",
         "cweagans/composer-patches": "^1.7.3",
diff --git a/composer.lock b/composer.lock
index 70aff03..987b558 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": "0f5b2ffee5049c1475a52b405be5330c",
+    "content-hash": "c74820aac3d28a03792ac245c52047ed",
     "packages": [
         {
             "name": "aws/aws-crt-php",
@@ -472,6 +472,83 @@
             ],
             "time": "2024-02-09T16:56:22+00:00"
         },
+        {
+            "name": "composer/semver",
+            "version": "3.4.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/composer/semver.git",
+                "reference": "198166618906cb2de69b95d7d47e5fa8aa1b2b95"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/composer/semver/zipball/198166618906cb2de69b95d7d47e5fa8aa1b2b95",
+                "reference": "198166618906cb2de69b95d7d47e5fa8aa1b2b95",
+                "shasum": ""
+            },
+            "require": {
+                "php": "^5.3.2 || ^7.0 || ^8.0"
+            },
+            "require-dev": {
+                "phpstan/phpstan": "^1.11",
+                "symfony/phpunit-bridge": "^3 || ^7"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-main": "3.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Composer\\Semver\\": "src"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nils Adermann",
+                    "email": "naderman@naderman.de",
+                    "homepage": "http://www.naderman.de"
+                },
+                {
+                    "name": "Jordi Boggiano",
+                    "email": "j.boggiano@seld.be",
+                    "homepage": "http://seld.be"
+                },
+                {
+                    "name": "Rob Bast",
+                    "email": "rob.bast@gmail.com",
+                    "homepage": "http://robbast.nl"
+                }
+            ],
+            "description": "Semver library that offers utilities, version constraint parsing and validation.",
+            "keywords": [
+                "semantic",
+                "semver",
+                "validation",
+                "versioning"
+            ],
+            "support": {
+                "irc": "ircs://irc.libera.chat:6697/composer",
+                "issues": "https://github.com/composer/semver/issues",
+                "source": "https://github.com/composer/semver/tree/3.4.4"
+            },
+            "funding": [
+                {
+                    "url": "https://packagist.com",
+                    "type": "custom"
+                },
+                {
+                    "url": "https://github.com/composer",
+                    "type": "github"
+                }
+            ],
+            "time": "2025-08-20T19:15:30+00:00"
+        },
         {
             "name": "crell/attributeutils",
             "version": "1.3.0",
@@ -9897,83 +9974,6 @@
             ],
             "time": "2024-11-12T16:29:46+00:00"
         },
-        {
-            "name": "composer/semver",
-            "version": "3.4.4",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/composer/semver.git",
-                "reference": "198166618906cb2de69b95d7d47e5fa8aa1b2b95"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/composer/semver/zipball/198166618906cb2de69b95d7d47e5fa8aa1b2b95",
-                "reference": "198166618906cb2de69b95d7d47e5fa8aa1b2b95",
-                "shasum": ""
-            },
-            "require": {
-                "php": "^5.3.2 || ^7.0 || ^8.0"
-            },
-            "require-dev": {
-                "phpstan/phpstan": "^1.11",
-                "symfony/phpunit-bridge": "^3 || ^7"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-main": "3.x-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "Composer\\Semver\\": "src"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Nils Adermann",
-                    "email": "naderman@naderman.de",
-                    "homepage": "http://www.naderman.de"
-                },
-                {
-                    "name": "Jordi Boggiano",
-                    "email": "j.boggiano@seld.be",
-                    "homepage": "http://seld.be"
-                },
-                {
-                    "name": "Rob Bast",
-                    "email": "rob.bast@gmail.com",
-                    "homepage": "http://robbast.nl"
-                }
-            ],
-            "description": "Semver library that offers utilities, version constraint parsing and validation.",
-            "keywords": [
-                "semantic",
-                "semver",
-                "validation",
-                "versioning"
-            ],
-            "support": {
-                "irc": "ircs://irc.libera.chat:6697/composer",
-                "issues": "https://github.com/composer/semver/issues",
-                "source": "https://github.com/composer/semver/tree/3.4.4"
-            },
-            "funding": [
-                {
-                    "url": "https://packagist.com",
-                    "type": "custom"
-                },
-                {
-                    "url": "https://github.com/composer",
-                    "type": "github"
-                }
-            ],
-            "time": "2025-08-20T19:15:30+00:00"
-        },
         {
             "name": "composer/xdebug-handler",
             "version": "3.0.5",
diff --git a/database/factories/PackageReleaseFactory.php b/database/factories/PackageReleaseFactory.php
index 322022c..0c4286c 100644
--- a/database/factories/PackageReleaseFactory.php
+++ b/database/factories/PackageReleaseFactory.php
@@ -19,7 +19,7 @@ public function definition(): array
             'version' => $this->faker->semver(),
             'download_url' => $this->faker->url(),
             'requires' => [
-                'php' => $this->faker->randomElement(['8.0', '8.1', '8.2', '8.3']),
+                'env:php' => $this->faker->randomElement(['^8.0', '^8.1', '^8.2', '^8.3']),
             ],
             'suggests' => [
                 'another-plugin' => $this->faker->semver(),
@@ -42,8 +42,13 @@ public function typo3(): static
     {
         return $this->state(fn () => [
             'requires' => [
-                'typo3' => $this->faker->randomElement(['11.5', '12.4', '13.4']),
-                'php' => $this->faker->randomElement(['8.1', '8.2', '8.3', '8.4']),
+                'env:typo3' => $this->faker->randomElement([
+                    '>=11.5.0 <=11.99.99',
+                    '>=12.4.0 <=12.99.99',
+                    '>=13.4.0 <=13.99.99',
+                    '>=11.5.0 <=12.99.99',
+                ]),
+                'env:php' => $this->faker->randomElement(['^8.1', '^8.2', '>=8.1']),
             ],
         ]);
     }
diff --git a/database/migrations/2026_03_22_000000_add_requires_gin_index_to_package_releases.php b/database/migrations/2026_03_22_000000_add_requires_gin_index_to_package_releases.php
new file mode 100644
index 0000000..bf03010
--- /dev/null
+++ b/database/migrations/2026_03_22_000000_add_requires_gin_index_to_package_releases.php
@@ -0,0 +1,18 @@
+<?php
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration {
+    public function up(): void
+    {
+        // GIN index on requires JSONB for fast key-existence checks (e.g. requires ? 'env:typo3')
+        DB::statement('CREATE INDEX package_releases_requires_gin ON package_releases USING GIN (requires)');
+    }
+
+    public function down(): void
+    {
+        DB::statement('DROP INDEX IF EXISTS package_releases_requires_gin');
+    }
+};
diff --git a/tests/Feature/API/FAIR/PackageSearchControllerTest.php b/tests/Feature/API/FAIR/PackageSearchControllerTest.php
index cbed670..e67f10a 100644
--- a/tests/Feature/API/FAIR/PackageSearchControllerTest.php
+++ b/tests/Feature/API/FAIR/PackageSearchControllerTest.php
@@ -183,37 +183,61 @@
         ]);
 });
 
-it('filters by requires version', function () {
-    // Package requiring TYPO3 11.5
+it('filters by requires version using Composer constraints', function () {
+    // Package supporting TYPO3 11.5–11.x
     $old = Package::factory()->withAuthors()->withMetas()->typo3Extension()
         ->create(['name' => 'Old Extension', 'slug' => 'old-ext']);
     $old->releases()->createMany(
         PackageReleaseFactory::new()->count(1)->make([
             'package_id' => $old->id,
-            'requires' => ['typo3' => '11.5', 'php' => '8.1'],
+            'requires' => ['env:typo3' => '>=11.5.0 <=11.99.99', 'env:php' => '^8.1'],
         ])->toArray(),
     );
 
-    // Package requiring TYPO3 13.4
+    // Package supporting TYPO3 13.4+
     $new = Package::factory()->withAuthors()->withMetas()->typo3Extension()
         ->create(['name' => 'New Extension', 'slug' => 'new-ext']);
     $new->releases()->createMany(
         PackageReleaseFactory::new()->count(1)->make([
             'package_id' => $new->id,
-            'requires' => ['typo3' => '13.4', 'php' => '8.2'],
+            'requires' => ['env:typo3' => '>=13.4.0 <=13.99.99', 'env:php' => '^8.2'],
         ])->toArray(),
     );
 
-    // Filter for TYPO3 12.4 — only the 11.5 package qualifies
-    $this->getJson('/packages/typo3-extension?requires[typo3]=12.4')
+    // Filter for TYPO3 11.5.19 — only the 11.x package qualifies
+    $this->getJson('/packages/typo3-extension?requires[env:typo3]=11.5.19')
         ->assertOk()
         ->assertJsonCount(1, 'packages')
         ->assertJsonPath('packages.0.name', 'Old Extension');
 
-    // Filter for TYPO3 13.4 — both qualify
-    $this->getJson('/packages/typo3-extension?requires[typo3]=13.4')
+    // Filter for TYPO3 13.4 — only the 13.x package qualifies
+    $this->getJson('/packages/typo3-extension?requires[env:typo3]=13.4')
         ->assertOk()
-        ->assertJsonCount(2, 'packages');
+        ->assertJsonCount(1, 'packages')
+        ->assertJsonPath('packages.0.name', 'New Extension');
+});
+
+it('excludes packages when version is outside constraint range', function () {
+    // Package supporting TYPO3 11.5–12.x
+    $pkg = Package::factory()->withAuthors()->withMetas()->typo3Extension()
+        ->create(['name' => 'Range Extension', 'slug' => 'range-ext']);
+    $pkg->releases()->createMany(
+        PackageReleaseFactory::new()->count(1)->make([
+            'package_id' => $pkg->id,
+            'requires' => ['env:typo3' => '>=11.5.19 <=12.9.99', 'env:php' => '^8.1'],
+        ])->toArray(),
+    );
+
+    // TYPO3 14.2 is above the upper bound — should return no packages
+    $this->getJson('/packages/typo3-extension?requires[env:typo3]=14.2')
+        ->assertOk()
+        ->assertJsonCount(0, 'packages');
+
+    // TYPO3 12.4 is within the range — should match
+    $this->getJson('/packages/typo3-extension?requires[env:typo3]=12.4')
+        ->assertOk()
+        ->assertJsonCount(1, 'packages')
+        ->assertJsonPath('packages.0.name', 'Range Extension');
 });
 
 it('filters by requires version combined with search', function () {
@@ -222,7 +246,7 @@
     $match->releases()->createMany(
         PackageReleaseFactory::new()->count(1)->make([
             'package_id' => $match->id,
-            'requires' => ['typo3' => '12.4', 'php' => '8.1'],
+            'requires' => ['env:typo3' => '>=12.4.0 <=12.99.99', 'env:php' => '^8.1'],
         ])->toArray(),
     );
 
@@ -231,16 +255,52 @@
     $tooNew->releases()->createMany(
         PackageReleaseFactory::new()->count(1)->make([
             'package_id' => $tooNew->id,
-            'requires' => ['typo3' => '13.4', 'php' => '8.3'],
+            'requires' => ['env:typo3' => '>=13.4.0 <=13.99.99', 'env:php' => '^8.3'],
         ])->toArray(),
     );
 
-    $this->getJson('/packages/typo3-extension?q=gallery&requires[typo3]=12.4')
+    $this->getJson('/packages/typo3-extension?q=gallery&requires[env:typo3]=12.4')
         ->assertOk()
         ->assertJsonCount(1, 'packages')
         ->assertJsonPath('packages.0.name', 'Gallery Pro');
 });
 
+it('only includes matching releases when filtering by requires', function () {
+    // Package with two releases: one for TYPO3 11.x and one for TYPO3 13.x
+    $package = Package::factory()->withAuthors()->withMetas()->typo3Extension()
+        ->create(['name' => 'Multi Release Ext', 'slug' => 'multi-release-ext']);
+
+    $package->releases()->createMany([
+        PackageReleaseFactory::new()->make([
+            'package_id' => $package->id,
+            'version' => '1.0.0',
+            'requires' => ['env:typo3' => '>=11.5.0 <=11.99.99', 'env:php' => '^8.1'],
+        ])->toArray(),
+        PackageReleaseFactory::new()->make([
+            'package_id' => $package->id,
+            'version' => '2.0.0',
+            'requires' => ['env:typo3' => '>=13.4.0 <=13.99.99', 'env:php' => '^8.2'],
+        ])->toArray(),
+    ]);
+
+    // Filter for TYPO3 11.5.19 — only the 11.x release qualifies
+    $response = $this->getJson('/packages/typo3-extension?requires[env:typo3]=11.5.19')
+        ->assertOk()
+        ->assertJsonCount(1, 'packages');
+
+    $releases = $response->json('packages.0.releases');
+    expect($releases)->toHaveCount(1);
+    expect($releases[0]['version'])->toBe('1.0.0');
+
+    // Without requires filter — both releases should be returned
+    $response = $this->getJson('/packages/typo3-extension')
+        ->assertOk()
+        ->assertJsonCount(1, 'packages');
+
+    $releases = $response->json('packages.0.releases');
+    expect($releases)->toHaveCount(2);
+});
+
 it('returns empty packages array with zero total when no results', function () {
     $this->getJson('/packages/typo3-extension?q=nonexistent')
         ->assertOk()