diff --git a/quiche/quic/core/http/http_decoder.cc b/quiche/quic/core/http/http_decoder.cc
index 2bdce8e..c6be41e 100644
--- a/quiche/quic/core/http/http_decoder.cc
+++ b/quiche/quic/core/http/http_decoder.cc
@@ -670,4 +670,16 @@
   }
 }
 
+std::string HttpDecoder::DebugString() const {
+  return absl::StrCat(
+      "HttpDecoder:", "\n  state: ", state_, "\n  error: ", error_,
+      "\n  current_frame_type: ", current_frame_type_,
+      "\n  current_length_field_length: ", current_length_field_length_,
+      "\n  remaining_length_field_length: ", remaining_length_field_length_,
+      "\n  current_frame_length: ", current_frame_length_,
+      "\n  remaining_frame_length: ", remaining_frame_length_,
+      "\n  current_type_field_length: ", current_type_field_length_,
+      "\n  remaining_type_field_length: ", remaining_type_field_length_);
+}
+
 }  // namespace quic
diff --git a/quiche/quic/core/http/http_decoder.h b/quiche/quic/core/http/http_decoder.h
index ac68276..0e49c3f 100644
--- a/quiche/quic/core/http/http_decoder.h
+++ b/quiche/quic/core/http/http_decoder.h
@@ -146,6 +146,8 @@
   // Returns true if input data processed so far ends on a frame boundary.
   bool AtFrameBoundary() const { return state_ == STATE_READING_FRAME_TYPE; }
 
+  std::string DebugString() const;
+
  private:
   friend test::HttpDecoderPeer;