diff --git a/lib/puma/app/status.rb b/lib/puma/app/status.rb
index f4ef9f2eeb..19f6d877de 100644
--- a/lib/puma/app/status.rb
+++ b/lib/puma/app/status.rb
@@ -57,9 +57,12 @@ def call(env)
           rack_response(200, @cli.stats)
 
         when /\/thread-backtraces$/
-          strings = Puma::Events.strings
-          @cli.log_thread_status(strings)
-          rack_response(200, strings.stdout.string)
+          backtraces = []
+          @cli.thread_status do |name, backtrace|
+            backtraces << { name: name, backtrace: backtrace }
+          end
+
+          rack_response(200, backtraces.to_json)
         else
           rack_response 404, "Unsupported action", 'text/plain'
         end
diff --git a/lib/puma/launcher.rb b/lib/puma/launcher.rb
index 0c93fb7663..81ba457051 100644
--- a/lib/puma/launcher.rb
+++ b/lib/puma/launcher.rb
@@ -205,18 +205,14 @@ def close_binder_listeners
       @binder.close_listeners
     end
 
-    def log_thread_status(events)
+    def thread_status
       Thread.list.each do |thread|
-        events.log "Thread TID-#{thread.object_id.to_s(36)} #{thread['label']}"
-        logstr = "Thread: TID-#{thread.object_id.to_s(36)}"
-        logstr += " #{thread.name}" if thread.respond_to?(:name)
-        events.log logstr
+        name = "Thread: TID-#{thread.object_id.to_s(36)}"
+        name += " #{thread['label']}" if thread['label']
+        name += " #{thread.name}" if thread.respond_to?(:name) && thread.name
+        backtrace = thread.backtrace || ["<no backtrace available>"]
 
-        if thread.backtrace
-          events.log thread.backtrace.join("\n")
-        else
-          events.log "<no backtrace available>"
-        end
+        yield name, backtrace
       end
     end
 
@@ -457,7 +453,10 @@ def setup_signals
 
       begin
         Signal.trap "SIGINFO" do
-          log_thread_status(@events)
+          thread_status do |name, backtrace|
+            @events.log name
+            @events.log backtrace
+          end
         end
       rescue Exception
         # Not going to log this one, as SIGINFO is *BSD only and would be pretty annoying
diff --git a/test/test_integration_cluster.rb b/test/test_integration_cluster.rb
index 9679f274fb..a7f58f84ec 100644
--- a/test/test_integration_cluster.rb
+++ b/test/test_integration_cluster.rb
@@ -44,7 +44,7 @@ def test_siginfo_thread_print
     Process.kill :INT , @pid
     t.join
 
-    assert_match "Thread TID", output.join
+    assert_match "Thread: TID", output.join
   end
 
   def test_usr2_restart
diff --git a/test/test_integration_single.rb b/test/test_integration_single.rb
index 8325231f50..7f44fde5fb 100644
--- a/test/test_integration_single.rb
+++ b/test/test_integration_single.rb
@@ -99,6 +99,6 @@ def test_siginfo_thread_print
     Process.kill :INT , @pid
     t.join
 
-    assert_match "Thread TID", output.join
+    assert_match "Thread: TID", output.join
   end
 end
diff --git a/test/test_launcher.rb b/test/test_launcher.rb
index 46b1f721ba..421703e2f7 100644
--- a/test/test_launcher.rb
+++ b/test/test_launcher.rb
@@ -57,10 +57,10 @@ def test_puma_wild_location_is_an_absolute_path
   end
 
   def test_prints_thread_traces
-    launcher.log_thread_status(events)
-    events.stdout.rewind
-
-    assert_match "Thread TID", events.stdout.read
+    launcher.thread_status do |name, backtrace|
+      assert_match "Thread: TID", name
+      refute_predicate backtrace, :empty?
+    end
   end
 
   def test_pid_file