diff --git a/UPGRADE-2.0.md b/UPGRADE-2.0.md
index ff6e6c597..fa2b176f4 100644
--- a/UPGRADE-2.0.md
+++ b/UPGRADE-2.0.md
@@ -74,3 +74,9 @@ If your repository only has a small number of packages, and you want to avoid th
 `"providers-api": "https://packagist.org/providers/%package%.json",`
 
 The providers-api is optional, but if you implement it it should return packages which provide a given package name, but not the package which has that name. For example https://packagist.org/providers/monolog/monolog.json lists some package which have a "provide" rule for monolog/monolog, but it does not list monolog/monolog itself.
+
+### list
+
+This is also optional, it should accept an optional `?filter=xx` query param, which can contain `*` as wildcards matching any substring.
+
+It must return an array of package names as `{"packageNames": ["a/b", "c/d"]}`. See https://packagist.org/packages/list.json?filter=composer/* for example.
diff --git a/src/Composer/Command/ShowCommand.php b/src/Composer/Command/ShowCommand.php
index b928765f9..c39aba760 100644
--- a/src/Composer/Command/ShowCommand.php
+++ b/src/Composer/Command/ShowCommand.php
@@ -299,8 +299,9 @@ EOT
 
         // list packages
         $packages = array();
+        $packageFilterRegex = null;
         if (null !== $packageFilter) {
-            $packageFilter = '{^'.str_replace('\\*', '.*?', preg_quote($packageFilter)).'$}i';
+            $packageFilterRegex = '{^'.str_replace('\\*', '.*?', preg_quote($packageFilter)).'$}i';
         }
 
         $packageListFilter = array();
@@ -342,10 +343,8 @@ EOT
                 $type = 'available';
             }
             if ($repo instanceof ComposerRepository) {
-                foreach ($repo->getPackageNames() as $name) {
-                    if (!$packageFilter || preg_match($packageFilter, $name)) {
-                        $packages[$type][$name] = $name;
-                    }
+                foreach ($repo->getPackageNames($packageFilter) as $name) {
+                    $packages[$type][$name] = $name;
                 }
             } else {
                 foreach ($repo->getPackages() as $package) {
@@ -353,7 +352,7 @@ EOT
                         || !is_object($packages[$type][$package->getName()])
                         || version_compare($packages[$type][$package->getName()]->getVersion(), $package->getVersion(), '<')
                     ) {
-                        if (!$packageFilter || preg_match($packageFilter, $package->getName())) {
+                        if (!$packageFilterRegex || preg_match($packageFilterRegex, $package->getName())) {
                             if (!$packageListFilter || in_array($package->getName(), $packageListFilter, true)) {
                                 $packages[$type][$package->getName()] = $package;
                             }
diff --git a/src/Composer/Repository/ComposerRepository.php b/src/Composer/Repository/ComposerRepository.php
index f7711390f..941cf08dd 100644
--- a/src/Composer/Repository/ComposerRepository.php
+++ b/src/Composer/Repository/ComposerRepository.php
@@ -58,6 +58,7 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
     protected $providersApiUrl;
     protected $hasProviders = false;
     protected $providersUrl;
+    protected $listUrl;
     protected $availablePackages;
     protected $lazyProvidersUrl;
     protected $providerListing;
@@ -288,32 +289,52 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
         return parent::getPackages();
     }
 
-    public function getPackageNames()
+    public function getPackageNames($packageFilter = null)
     {
-        // TODO add getPackageNames to the RepositoryInterface perhaps? With filtering capability embedded?
         $hasProviders = $this->hasProviders();
 
+        $packageFilterCb = function ($name) {
+            return true;
+        };
+        if (null !== $packageFilter) {
+            $packageFilterRegex = '{^'.str_replace('\\*', '.*?', preg_quote($packageFilter)).'$}i';
+            $packageFilterCb = function ($name) use ($packageFilterRegex) {
+                return (bool) preg_match($packageFilterRegex, $name);
+            };
+        }
+
         if ($this->lazyProvidersUrl) {
             if (is_array($this->availablePackages)) {
-                return array_keys($this->availablePackages);
+                return array_filter(array_keys($this->availablePackages), $packageFilterCb);
             }
 
-            // TODO implement new list API endpoint for those repos somehow?
+            if ($this->listUrl) {
+                $url = $this->listUrl;
+                if ($packageFilter) {
+                    $url .= '?filter='.urlencode($packageFilter);
+                }
+
+                $result = $this->httpDownloader->get($url, $this->options)->decodeJson();
+
+                return $result['packageNames'];
+            }
 
             if ($this->hasPartialPackages()) {
-                return array_keys($this->partialPackagesByName);
+                return array_filter(array_keys($this->partialPackagesByName), $packageFilterCb);
             }
 
             return array();
         }
 
         if ($hasProviders) {
-            return $this->getProviderNames();
+            return array_filter($this->getProviderNames(), $packageFilterCb);
         }
 
         $names = array();
         foreach ($this->getPackages() as $package) {
-            $names[] = $package->getPrettyName();
+            if ($packageFilterCb($package->getName())) {
+                $names[] = $package->getPrettyName();
+            }
         }
 
         return $names;
@@ -866,6 +887,10 @@ class ComposerRepository extends ArrayRepository implements ConfigurableReposito
             $this->hasProviders = true;
         }
 
+        if (!empty($data['list'])) {
+            $this->listUrl = $this->canonicalizeUrl($data['list']);
+        }
+
         if (!empty($data['providers']) || !empty($data['providers-includes'])) {
             $this->hasProviders = true;
         }