diff --git a/app/flatpages/help/api.md b/app/flatpages/help/api.md
index 6d2aadf0..6f30be25 100644
--- a/app/flatpages/help/api.md
+++ b/app/flatpages/help/api.md
@@ -186,6 +186,7 @@ Supported query parameters:
 * `q`:  Query string.
 * `author`:  Filter by author.
 * `tag`:  Filter by tags.
+* `flag`: Filter to show packages with [Content Flags](/help/content_flags/).
 * `game`: Filter by [Game Support](/help/game_support/), ex: `Wuzzy/mineclone2`. (experimental, doesn't show items that support every game currently).
 * `random`:  When present, enable random ordering and ignore `sort`.
 * `limit`:  Return at most `limit` packages.
diff --git a/app/querybuilder.py b/app/querybuilder.py
index ad5e4667..143a7418 100644
--- a/app/querybuilder.py
+++ b/app/querybuilder.py
@@ -70,6 +70,9 @@ class QueryBuilder:
 		# Hide
 		self.hide_flags = set(args.getlist("hide"))
 
+		# Show flags
+		self.flags = set(args.getlist("flag"))
+
 		self.types  = types
 		self.tags   = tags
 
@@ -188,6 +191,27 @@ class QueryBuilder:
 				if warning:
 					query = query.filter(~ Package.content_warnings.any(ContentWarning.id == warning.id))
 
+		flags = set(self.flags)
+		if "nonfree" in flags:
+			query = query.filter(or_(Package.license.has(is_foss=False), Package.media_license.has(is_foss=False)))
+			flags.discard("nonfree")
+		if "wip" in flags:
+			query = query.filter(Package.dev_state == PackageDevState.WIP)
+			flags.discard("wip")
+		if "deprecated" in flags:
+			query = query.filter(Package.dev_state == PackageDevState.DEPRECATED)
+			flags.discard("deprecated")
+
+		if "*" in flags:
+			query = query.filter(Package.content_warnings.any())
+			flags.discard("*")
+		else:
+			for flag in flags:
+				warning = ContentWarning.query.filter_by(name=flag).first()
+				flags.discard(flag)
+				if warning:
+					query = query.filter(Package.content_warnings.any(ContentWarning.id == warning.id))
+
 		if self.hide_nonfree:
 			query = query.filter(Package.license.has(License.is_foss == True))
 			query = query.filter(Package.media_license.has(License.is_foss == True))