diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index d67bd2645ac0c..7ff479ab28ba6 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,8 +1,11 @@
+*   Allow Content Security Policy DSL to generate for API responses.
+
+    *Tim Wade*
+
 ## Rails 5.2.7 (March 10, 2022) ##
 
 *   No changes.
 
-
 ## Rails 5.2.6.3 (March 08, 2022) ##
 
 *   No changes.
diff --git a/actionpack/lib/action_dispatch/http/content_security_policy.rb b/actionpack/lib/action_dispatch/http/content_security_policy.rb
index 6f9fb11a2950b..69ac64c5a3142 100644
--- a/actionpack/lib/action_dispatch/http/content_security_policy.rb
+++ b/actionpack/lib/action_dispatch/http/content_security_policy.rb
@@ -17,7 +17,6 @@ def call(env)
         request = ActionDispatch::Request.new env
         _, headers, _ = response = @app.call(env)
 
-        return response unless html_response?(headers)
         return response if policy_present?(headers)
 
         if policy = request.content_security_policy
@@ -30,13 +29,6 @@ def call(env)
       end
 
       private
-
-        def html_response?(headers)
-          if content_type = headers[CONTENT_TYPE]
-            content_type =~ /html/
-          end
-        end
-
         def header_name(request)
           if request.content_security_policy_report_only
             POLICY_REPORT_ONLY
diff --git a/actionpack/test/dispatch/content_security_policy_test.rb b/actionpack/test/dispatch/content_security_policy_test.rb
index 71ac63def2184..25feb4c258826 100644
--- a/actionpack/test/dispatch/content_security_policy_test.rb
+++ b/actionpack/test/dispatch/content_security_policy_test.rb
@@ -343,6 +343,11 @@ class PolicyController < ActionController::Base
 
     content_security_policy_report_only only: :report_only
 
+    content_security_policy only: :api do |p|
+      p.default_src :none
+      p.frame_ancestors :none
+    end
+
     def index
       head :ok
     end
@@ -367,6 +372,10 @@ def no_policy
       head :ok
     end
 
+    def api
+      render json: {}
+    end
+
     private
       def condition?
         params[:condition] == "true"
@@ -382,6 +391,7 @@ def condition?
       get "/report-only", to: "policy#report_only"
       get "/script-src", to: "policy#script_src"
       get "/no-policy", to: "policy#no_policy"
+      get "/api", to: "policy#api"
     end
   end
 
@@ -448,6 +458,11 @@ def test_generates_no_content_security_policy
     assert_nil response.headers["Content-Security-Policy-Report-Only"]
   end
 
+  def test_generates_api_security_policy
+    get "/api"
+    assert_policy "default-src 'none'; frame-ancestors 'none'"
+  end
+
   private
 
     def assert_policy(expected, report_only: false)