diff --git a/src/command_line.cc b/src/command_line.cc
index 6ca7236f..5c4850da 100644
--- a/src/command_line.cc
+++ b/src/command_line.cc
@@ -18,6 +18,7 @@
 #include "query.h"
 #include "query_utils.h"
 #include "queue_manager.h"
+#include "recorder.h"
 #include "semantic_highlight_symbol_cache.h"
 #include "serializer.h"
 #include "serializers/json.h"
@@ -56,9 +57,6 @@ namespace {
 
 std::vector<std::string> kEmptyArgs;
 
-// If true stdout will be printed to stderr.
-bool g_log_stdin_stdout_to_stderr = false;
-
 // This function returns true if e2e timing should be displayed for the given
 // IpcId.
 bool ShouldDisplayIpcTiming(IpcId id) {
@@ -96,8 +94,8 @@ Other command line options:
   --init <initializationOptions>
                 Override client provided initialization options
          https://github.com/cquery-project/cquery/wiki/Initialization-options
-  --log-stdin-stdout-to-stderr
-                Print stdin (requests) and stdout (responses) to stderr
+  --record <path>
+                Writes stdin to <path>.in and stdout to <path>.out
   --log-file <path>    Logging file for diagnostics
   --log-all-to-stderr  Write all log messages to STDERR.
   --wait-for-input     Wait for an '[Enter]' before exiting
@@ -273,8 +271,7 @@ void LaunchStdinLoop(Config* config,
     while (true) {
       std::unique_ptr<BaseIpcMessage> message;
       optional<std::string> err =
-          MessageRegistry::instance()->ReadMessageFromStdin(
-              g_log_stdin_stdout_to_stderr, &message);
+          MessageRegistry::instance()->ReadMessageFromStdin(&message);
 
       // Message parsing can fail if we don't recognize the method.
       if (err) {
@@ -381,10 +378,7 @@ void LaunchStdoutThread(std::unordered_map<IpcId, Timer>* request_times,
                              std::string(IpcIdToString(message.id)));
         }
 
-        if (g_log_stdin_stdout_to_stderr) {
-          std::cerr << "[COUT] |" << message.content << "|\n";
-          std::cerr.flush();
-        }
+        RecordOutput(message.content);
 
         std::cout << message.content;
         std::cout.flush();
@@ -460,8 +454,8 @@ int main(int argc, char** argv) {
                      loguru::Verbosity_MAX);
   }
 
-  if (HasOption(options, "--log-stdin-stdout-to-stderr"))
-    g_log_stdin_stdout_to_stderr = true;
+  if (HasOption(options, "--record"))
+    EnableRecording(options["--record"]);
 
   if (HasOption(options, "--clang-sanity-check")) {
     language_server = false;
diff --git a/src/language_server_api.cc b/src/language_server_api.cc
index d8889f24..88215d6f 100644
--- a/src/language_server_api.cc
+++ b/src/language_server_api.cc
@@ -1,5 +1,6 @@
 #include "language_server_api.h"
 
+#include "recorder.h"
 #include "serializers/json.h"
 
 #include <doctest/doctest.h>
@@ -65,6 +66,8 @@ optional<std::string> ReadJsonRpcContentFrom(
     content += *c;
   }
 
+  RecordInput(content);
+
   return content;
 }
 
@@ -119,7 +122,6 @@ optional<char> ReadCharFromStdinBlocking() {
 }
 
 optional<std::string> MessageRegistry::ReadMessageFromStdin(
-    bool log_stdin_to_stderr,
     std::unique_ptr<BaseIpcMessage>* message) {
   optional<std::string> content =
       ReadJsonRpcContentFrom(&ReadCharFromStdinBlocking);
@@ -128,14 +130,6 @@ optional<std::string> MessageRegistry::ReadMessageFromStdin(
     exit(1);
   }
 
-  if (log_stdin_to_stderr) {
-    // TODO: This should go inside of ReadJsonRpcContentFrom since it does not
-    // print the header.
-    std::string printed = "[CIN] |" + *content + "|\n";
-    std::cerr << printed;
-    std::cerr.flush();
-  }
-
   rapidjson::Document document;
   document.Parse(content->c_str(), content->length());
   assert(!document.HasParseError());
diff --git a/src/language_server_api.h b/src/language_server_api.h
index ba52bec8..95aca47d 100644
--- a/src/language_server_api.h
+++ b/src/language_server_api.h
@@ -43,7 +43,6 @@ struct MessageRegistry {
   std::unordered_map<std::string, Allocator> allocators;
 
   optional<std::string> ReadMessageFromStdin(
-      bool log_stdin_to_stderr,
       std::unique_ptr<BaseIpcMessage>* message);
   optional<std::string> Parse(Reader& visitor,
                               std::unique_ptr<BaseIpcMessage>* message);
diff --git a/src/recorder.cc b/src/recorder.cc
new file mode 100644
index 00000000..6da3081e
--- /dev/null
+++ b/src/recorder.cc
@@ -0,0 +1,56 @@
+#include "recorder.h"
+
+#include <loguru.hpp>
+
+#include <cassert>
+#include <fstream>
+
+namespace {
+std::ofstream* g_file_in = nullptr;
+std::ofstream* g_file_out = nullptr;
+}  // namespace
+
+void EnableRecording(std::string path) {
+  if (path.empty())
+    path = "cquery";
+
+  // We can only call |EnableRecording| once.
+  assert(!g_file_in && !g_file_out);
+
+  // Open the files.
+  g_file_in = new std::ofstream(path + ".in",
+      std::ios::out | std::ios::trunc | std::ios::binary);
+  g_file_out = new std::ofstream(path + ".out",
+    std::ios::out | std::ios::trunc | std::ios::binary);
+
+  // Make sure we can write to the files.
+  bool bad = false;
+  if (!g_file_in->good()) {
+    LOG_S(ERROR) << "record: cannot write to " << path << ".in";
+    bad = true;
+  }
+  if (!g_file_out->good()) {
+    LOG_S(ERROR) << "record: cannot write to " << path << ".out";
+    bad = true;
+  }
+  if (bad) {
+    delete g_file_in;
+    delete g_file_out;
+    g_file_in = nullptr;
+    g_file_out = nullptr;
+  }
+}
+
+void RecordInput(std::string_view content) {
+  if (!g_file_in)
+    return;
+  (*g_file_in) << "Content-Length: " << content.size() << "\r\n\r\n" << content;
+  (*g_file_in).flush();
+}
+
+void RecordOutput(std::string_view content) {
+  if (!g_file_out)
+    return;
+  (*g_file_out) << content;
+  (*g_file_out).flush();
+}
\ No newline at end of file
diff --git a/src/recorder.h b/src/recorder.h
new file mode 100644
index 00000000..772841d3
--- /dev/null
+++ b/src/recorder.h
@@ -0,0 +1,9 @@
+#pragma once
+
+#include <string_view.h>
+
+#include <string>
+
+void EnableRecording(std::string path);
+void RecordInput(std::string_view content);
+void RecordOutput(std::string_view content);
\ No newline at end of file