diff --git a/docker/development/Dockerfile b/docker/development/Dockerfile
index 6297da2cfe..9268309552 100644
--- a/docker/development/Dockerfile
+++ b/docker/development/Dockerfile
@@ -8,6 +8,8 @@ ARG CLOUDFLARED_VERSION=2025.7.0
 ARG POSTGRES_VERSION=18
 # https://nginx.org/en/linux_packages.html
 ARG NGINX_VERSION=1.31.2-r1
+# https://pecl.php.net/package/uv
+ARG PHP_UV_VERSION=0.3.0
 
 # =================================================================
 # Get MinIO client
@@ -26,6 +28,7 @@ ARG TARGETARCH
 ARG POSTGRES_VERSION
 ARG CLOUDFLARED_VERSION
 ARG NGINX_VERSION
+ARG PHP_UV_VERSION
 
 WORKDIR /var/www/html
 
@@ -70,7 +73,8 @@ RUN apk add --no-cache \
     vim
 
 # Install PHP extensions
-RUN install-php-extensions sockets
+# uv: Reverb uses an ext-uv event loop instead of stream_select(), which fails at 1024 open files (FD_SETSIZE)
+RUN install-php-extensions sockets uv-${PHP_UV_VERSION}
 
 # Configure shell aliases
 RUN echo "alias ll='ls -al'" >> /etc/profile && \
diff --git a/docker/development/etc/s6-overlay/s6-rc.d/reverb/run b/docker/development/etc/s6-overlay/s6-rc.d/reverb/run
index e35e88a6cb..270d248a97 100755
--- a/docker/development/etc/s6-overlay/s6-rc.d/reverb/run
+++ b/docker/development/etc/s6-overlay/s6-rc.d/reverb/run
@@ -2,5 +2,21 @@
 
 cd /var/www/html
 
+# Every WebSocket connection uses a file descriptor. Raise the soft open-file limit (often 1024)
+# up to the hard limit, at most 65536. Never lower it, and start Reverb even when this fails.
+# Only with an event loop extension (uv, ev, event): the default stream_select() loop fails for
+# every connection once one descriptor is 1024 or higher (FD_SETSIZE), so it keeps the limit.
+if php -r 'exit(function_exists("uv_loop_new") || class_exists("EvLoop", false) || class_exists("EventBase", false) ? 0 : 1);'; then
+    target=65536
+    hard=$(ulimit -Hn)
+    if [ "$hard" != "unlimited" ] && [ "$hard" -lt "$target" ] 2>/dev/null; then
+        target=$hard
+    fi
+    soft=$(ulimit -Sn)
+    if [ "$soft" != "unlimited" ] && [ "$soft" -lt "$target" ] 2>/dev/null; then
+        ulimit -Sn "$target" 2>/dev/null || echo "   WARN  Could not raise the open-file limit of Reverb from $soft to $target."
+    fi
+fi
+
 echo "   INFO  Reverb is starting..."
 exec php artisan reverb:start --host=0.0.0.0 --port=${PUSHER_BACKEND_PORT:-6001}
diff --git a/docker/production/Dockerfile b/docker/production/Dockerfile
index 03d1145df7..a751000bff 100644
--- a/docker/production/Dockerfile
+++ b/docker/production/Dockerfile
@@ -8,6 +8,8 @@ ARG CLOUDFLARED_VERSION=2026.7.3
 ARG POSTGRES_VERSION=18
 # https://nginx.org/en/linux_packages.html
 ARG NGINX_VERSION=1.31.2-r1
+# https://pecl.php.net/package/uv
+ARG PHP_UV_VERSION=0.3.0
 
 # Add user/group
 ARG USER_ID=9999
@@ -74,6 +76,7 @@ ARG TARGETPLATFORM
 ARG POSTGRES_VERSION
 ARG CLOUDFLARED_VERSION
 ARG NGINX_VERSION
+ARG PHP_UV_VERSION
 ARG COOLIFY_VERSION
 ARG CI=true
 
@@ -120,6 +123,10 @@ RUN --mount=type=cache,target=/var/cache/apk \
     lsof \
     vim
 
+# Install PHP extensions
+# uv: Reverb uses an ext-uv event loop instead of stream_select(), which fails at 1024 open files (FD_SETSIZE)
+RUN install-php-extensions uv-${PHP_UV_VERSION}
+
 # Configure shell aliases
 RUN echo "alias ll='ls -al'" >> /etc/profile && \
     echo "alias a='php artisan'" >> /etc/profile && \
diff --git a/docker/production/etc/s6-overlay/s6-rc.d/reverb/run b/docker/production/etc/s6-overlay/s6-rc.d/reverb/run
index e35e88a6cb..270d248a97 100755
--- a/docker/production/etc/s6-overlay/s6-rc.d/reverb/run
+++ b/docker/production/etc/s6-overlay/s6-rc.d/reverb/run
@@ -2,5 +2,21 @@
 
 cd /var/www/html
 
+# Every WebSocket connection uses a file descriptor. Raise the soft open-file limit (often 1024)
+# up to the hard limit, at most 65536. Never lower it, and start Reverb even when this fails.
+# Only with an event loop extension (uv, ev, event): the default stream_select() loop fails for
+# every connection once one descriptor is 1024 or higher (FD_SETSIZE), so it keeps the limit.
+if php -r 'exit(function_exists("uv_loop_new") || class_exists("EvLoop", false) || class_exists("EventBase", false) ? 0 : 1);'; then
+    target=65536
+    hard=$(ulimit -Hn)
+    if [ "$hard" != "unlimited" ] && [ "$hard" -lt "$target" ] 2>/dev/null; then
+        target=$hard
+    fi
+    soft=$(ulimit -Sn)
+    if [ "$soft" != "unlimited" ] && [ "$soft" -lt "$target" ] 2>/dev/null; then
+        ulimit -Sn "$target" 2>/dev/null || echo "   WARN  Could not raise the open-file limit of Reverb from $soft to $target."
+    fi
+fi
+
 echo "   INFO  Reverb is starting..."
 exec php artisan reverb:start --host=0.0.0.0 --port=${PUSHER_BACKEND_PORT:-6001}
diff --git a/tests/Feature/ReverbOpenFileLimitTest.php b/tests/Feature/ReverbOpenFileLimitTest.php
new file mode 100644
index 0000000000..f8231b5b24
--- /dev/null
+++ b/tests/Feature/ReverbOpenFileLimitTest.php
@@ -0,0 +1,57 @@
+<?php
+
+use Illuminate\Support\Facades\File;
+use Illuminate\Support\Facades\Process;
+
+/**
+ * Reverb keeps one file descriptor per WebSocket connection. With an event loop extension its s6 run
+ * script raises the soft open-file limit up to the hard limit (at most 65536) and still starts when it
+ * cannot. Without one, ReactPHP uses stream_select(), which fails for every connection once a
+ * descriptor reaches FD_SETSIZE (1024), so the limit must stay.
+ */
+beforeEach(function () {
+    $this->bin = sys_get_temp_dir().'/reverb-open-files-'.bin2hex(random_bytes(4));
+    File::makeDirectory($this->bin);
+    // Answers the event loop extension probe (`php -r`) from FAKE_LOOP_EXTENSION, and stands in for
+    // `php artisan reverb:start` by reporting the limit Reverb would get.
+    File::put("{$this->bin}/php", "#!/bin/sh\nif [ \"\$1\" = \"-r\" ]; then [ \"\$FAKE_LOOP_EXTENSION\" = yes ]; exit \$?; fi\necho \"soft=\$(ulimit -Sn)\"\n");
+    chmod("{$this->bin}/php", 0755);
+});
+
+afterEach(function () {
+    File::deleteDirectory($this->bin);
+});
+
+function reverbSoftOpenFileLimit(string $runScript, string $hardLimit, string $softLimit, string $bin, bool $loopExtension = true): string
+{
+    $result = Process::env(['PATH' => "{$bin}:/usr/bin:/bin", 'FAKE_LOOP_EXTENSION' => $loopExtension ? 'yes' : 'no'])->run(sprintf(
+        // The soft limit is lowered first: a hard limit below the current soft limit is invalid.
+        'ulimit -Sn %s && ulimit -Hn %s && exec sh %s',
+        $softLimit,
+        $hardLimit,
+        escapeshellarg(base_path($runScript)),
+    ));
+
+    expect($result->successful())->toBeTrue();
+
+    return trim(str($result->output())->afterLast('soft='));
+}
+
+it('raises the reverb soft open-file limit up to the hard limit, at most 65536', function (string $runScript, string $hardLimit, string $softLimit, string $expected) {
+    expect(reverbSoftOpenFileLimit($runScript, $hardLimit, $softLimit, $this->bin))->toBe($expected);
+})->with([
+    'production' => 'docker/production/etc/s6-overlay/s6-rc.d/reverb/run',
+    'development' => 'docker/development/etc/s6-overlay/s6-rc.d/reverb/run',
+])->with([
+    'hard limit below the cap' => ['4096', '1024', '4096'],
+    'hard limit above the cap' => ['200000', '1024', '65536'],
+    'hard limit equal to the soft limit' => ['1024', '1024', '1024'],
+    'soft limit already above the cap' => ['200000', '100000', '100000'],
+]);
+
+it('keeps the reverb soft open-file limit without an event loop extension', function (string $runScript) {
+    expect(reverbSoftOpenFileLimit($runScript, '4096', '1024', $this->bin, loopExtension: false))->toBe('1024');
+})->with([
+    'production' => 'docker/production/etc/s6-overlay/s6-rc.d/reverb/run',
+    'development' => 'docker/development/etc/s6-overlay/s6-rc.d/reverb/run',
+]);