diff --git a/rcl/CMakeLists.txt b/rcl/CMakeLists.txt
index b61cd06f5..43657cdef 100644
--- a/rcl/CMakeLists.txt
+++ b/rcl/CMakeLists.txt
@@ -2,13 +2,13 @@ cmake_minimum_required(VERSION 3.20)
 
 project(rcl)
 
+option(RCL_MICROROS "micro-ROS build mode" OFF)
+
 find_package(ament_cmake_ros REQUIRED)
 find_package(ament_cmake_gen_version_h REQUIRED)
 
-find_package(libyaml_vendor REQUIRED)
 find_package(rcl_interfaces REQUIRED)
 find_package(rcl_logging_interface REQUIRED)
-find_package(rcl_yaml_param_parser REQUIRED)
 find_package(rcutils REQUIRED)
 find_package(rmw REQUIRED)
 find_package(rmw_implementation REQUIRED)
@@ -16,14 +16,20 @@ find_package(rosidl_runtime_c REQUIRED)
 find_package(service_msgs REQUIRED)
 find_package(tracetools REQUIRED)
 find_package(type_description_interfaces REQUIRED)
-find_package(yaml REQUIRED)
+if(NOT RCL_MICROROS)
+  find_package(libyaml_vendor REQUIRED)
+  find_package(rcl_yaml_param_parser REQUIRED)
+  find_package(yaml REQUIRED)
+endif()
 
 include(cmake/rcl_set_symbol_visibility_hidden.cmake)
 
-# Determine the logging implementation to use
-include(cmake/get_default_rcl_logging_implementation.cmake)
-get_default_rcl_logging_implementation(RCL_LOGGING_IMPL)
-message(STATUS "RCL_LOGGING_IMPLEMENTATION: ${RCL_LOGGING_IMPL}")
+if(NOT RCL_MICROROS)
+  # Determine the logging implementation to use
+  include(cmake/get_default_rcl_logging_implementation.cmake)
+  get_default_rcl_logging_implementation(RCL_LOGGING_IMPL)
+  message(STATUS "RCL_LOGGING_IMPLEMENTATION: ${RCL_LOGGING_IMPL}")
+endif()
 
 # Default to C11
 if(NOT CMAKE_C_STANDARD)
@@ -41,7 +47,7 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
 endif()
 
 set(${PROJECT_NAME}_sources
-  src/rcl/arguments.c
+  $<$<NOT:$<BOOL:${RCL_MICROROS}>>:src/rcl/arguments.c>
   src/rcl/client.c
   src/rcl/common.c
   src/rcl/context.c
@@ -57,13 +63,13 @@ set(${PROJECT_NAME}_sources
   src/rcl/init_options.c
   src/rcl/lexer.c
   src/rcl/lexer_lookahead.c
-  src/rcl/logging_rosout.c
-  src/rcl/logging.c
-  src/rcl/log_level.c
+  $<$<NOT:$<BOOL:${RCL_MICROROS}>>:src/rcl/logging_rosout.c>
+  $<$<NOT:$<BOOL:${RCL_MICROROS}>>:src/rcl/logging.c>
+  $<$<NOT:$<BOOL:${RCL_MICROROS}>>:src/rcl/log_level.c>
   src/rcl/network_flow_endpoints.c
   src/rcl/node.c
   src/rcl/node_options.c
-  src/rcl/node_type_cache.c
+  $<$<NOT:$<BOOL:${RCL_MICROROS}>>:src/rcl/node_type_cache.c>
   src/rcl/publisher.c
   src/rcl/remap.c
   src/rcl/node_resolve_name.c
@@ -75,13 +81,16 @@ set(${PROJECT_NAME}_sources
   src/rcl/time.c
   src/rcl/timer.c
   src/rcl/type_hash.c
-  src/rcl/type_description_conversions.c
+  $<$<NOT:$<BOOL:${RCL_MICROROS}>>:src/rcl/type_description_conversions.c>
   src/rcl/validate_enclave_name.c
   src/rcl/validate_topic_name.c
   src/rcl/wait.c
 )
 
 add_library(${PROJECT_NAME} ${${PROJECT_NAME}_sources})
+if(RCL_MICROROS)
+  target_compile_definitions(${PROJECT_NAME} PUBLIC RCL_MICROROS)
+endif()
 target_include_directories(${PROJECT_NAME} PUBLIC
   "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>"
   "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/src>"
@@ -91,7 +100,6 @@ target_link_libraries(${PROJECT_NAME} PUBLIC
   rcl_interfaces::rcl_interfaces
   # TODO(clalancette): rcl_logging_interface should be PRIVATE, but downstream depends on it for now
   rcl_logging_interface::rcl_logging_interface
-  rcl_yaml_param_parser::rcl_yaml_param_parser
   rcutils::rcutils
   rmw::rmw
   # TODO(clalancette): rmw_implementation should be PRIVATE, but downstream depends on it for now
@@ -99,25 +107,37 @@ target_link_libraries(${PROJECT_NAME} PUBLIC
   rosidl_runtime_c::rosidl_runtime_c
   type_description_interfaces::type_description_interfaces
 )
+if(NOT RCL_MICROROS)
+  target_link_libraries(${PROJECT_NAME} PUBLIC
+    rcl_yaml_param_parser::rcl_yaml_param_parser
+  )
+endif()
+
 target_link_libraries(${PROJECT_NAME} PRIVATE
-  service_msgs::service_msgs
   tracetools::tracetools
-  yaml
 )
-
-# Link logging implementation based on configuration
-if(RCL_LOGGING_IMPL STREQUAL "rcl_logging_implementation")
-  # Dynamic loading: use rcl_logging_implementation abstraction
-  target_link_libraries(${PROJECT_NAME} PRIVATE
-    rcl_logging_implementation::rcl_logging_implementation
-  )
-else()
-  # Static linking: use specific logging implementation
+if(NOT RCL_MICROROS)
   target_link_libraries(${PROJECT_NAME} PRIVATE
-    ${RCL_LOGGING_IMPL}::${RCL_LOGGING_IMPL}
+    service_msgs::service_msgs
+    yaml
   )
 endif()
 
+if(NOT RCL_MICROROS)
+  # Link logging implementation based on configuration
+  if(RCL_LOGGING_IMPL STREQUAL "rcl_logging_implementation")
+    # Dynamic loading: use rcl_logging_implementation abstraction
+    target_link_libraries(${PROJECT_NAME} PRIVATE
+      rcl_logging_implementation::rcl_logging_implementation
+    )
+  else()
+    # Static linking: use specific logging implementation
+    target_link_libraries(${PROJECT_NAME} PRIVATE
+      ${RCL_LOGGING_IMPL}::${RCL_LOGGING_IMPL}
+    )
+  endif()
+endif()
+
 # Allow configuring the default discovery range
 if(DEFINED RCL_DEFAULT_DISCOVERY_RANGE)
 target_compile_definitions(${PROJECT_NAME} PRIVATE
@@ -156,13 +176,16 @@ ament_export_dependencies(ament_cmake)
 ament_export_dependencies(rcl_interfaces)
 # TODO(clalancette): rcl_logging_interface shouldn't be exported, but downstream depends on it for now
 ament_export_dependencies(rcl_logging_interface)
-ament_export_dependencies(rcl_yaml_param_parser)
 ament_export_dependencies(rcutils)
 ament_export_dependencies(rmw)
 # TODO(clalancette): rmw_implementation shouldn't be exported, but downstream depends on it for now
 ament_export_dependencies(rmw_implementation)
 ament_export_dependencies(rosidl_runtime_c)
+ament_export_dependencies(tracetools)
 ament_export_dependencies(type_description_interfaces)
+if(NOT RCL_MICROROS)
+  ament_export_dependencies(rcl_yaml_param_parser)
+endif()
 ament_generate_version_header(${PROJECT_NAME})
 
 if(BUILD_TESTING)
diff --git a/rcl/include/rcl/arguments.h b/rcl/include/rcl/arguments.h
index d37363999..d1371cb5d 100644
--- a/rcl/include/rcl/arguments.h
+++ b/rcl/include/rcl/arguments.h
@@ -22,7 +22,11 @@
 #include "rcl/macros.h"
 #include "rcl/types.h"
 #include "rcl/visibility_control.h"
+#ifndef RCL_MICROROS
 #include "rcl_yaml_param_parser/types.h"
+#else
+typedef bool rcl_params_t;
+#endif  // RCL_MICROROS
 
 #ifdef __cplusplus
 extern "C"
diff --git a/rcl/include/rcl/context.h b/rcl/include/rcl/context.h
index 68500da81..23fbbfe5c 100644
--- a/rcl/include/rcl/context.h
+++ b/rcl/include/rcl/context.h
@@ -25,7 +25,9 @@ extern "C"
 #include "rmw/init.h"
 
 #include "rcl/allocator.h"
+#ifndef RCL_MICROROS
 #include "rcl/arguments.h"
+#endif  // RCL_MICROROS
 #include "rcl/init_options.h"
 #include "rcl/macros.h"
 #include "rcl/types.h"
@@ -112,9 +114,11 @@ typedef struct rcl_context_impl_s rcl_context_impl_t;
  */
 typedef struct rcl_context_s
 {
+#ifndef RCL_MICROROS
   /// Global arguments for all nodes which share this context.
   /** Typically generated by the parsing of argc/argv in rcl_init(). */
   rcl_arguments_t global_arguments;
+#endif  // RCL_MICROROS
 
   /// Implementation specific pointer.
   rcl_context_impl_t * impl;
@@ -123,7 +127,7 @@ typedef struct rcl_context_s
   // ensured with a static_assert in the context.c file.
   // In most cases it should just be a plain uint64_t.
 /// @cond Doxygen_Suppress
-#if !defined(RCL_CONTEXT_ATOMIC_INSTANCE_ID_STORAGE_SIZE)
+#if !defined(RCL_CONTEXT_ATOMIC_INSTANCE_ID_STORAGE_SIZE) && !defined(RCL_MICROROS)
 #define RCL_CONTEXT_ATOMIC_INSTANCE_ID_STORAGE_SIZE sizeof(uint_least64_t)
 #endif
 /// @endcond
@@ -146,7 +150,11 @@ typedef struct rcl_context_s
    * See this paper for an effort to make this possible in the future:
    *   http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0943r1.html
    */
+#ifdef RCL_MICROROS
+  uint32_t instance_id_storage;
+#else
   RCL_ALIGNAS(8) uint8_t instance_id_storage[RCL_CONTEXT_ATOMIC_INSTANCE_ID_STORAGE_SIZE];
+#endif  // RCL_MICROROS
 } rcl_context_t;
 
 /// Return a zero initialization context object.
diff --git a/rcl/include/rcl/node.h b/rcl/include/rcl/node.h
index 58a2163ec..cf3193090 100644
--- a/rcl/include/rcl/node.h
+++ b/rcl/include/rcl/node.h
@@ -25,7 +25,9 @@ extern "C"
 #include <stdint.h>
 
 #include "rcl/allocator.h"
+#ifndef RCL_MICROROS
 #include "rcl/arguments.h"
+#endif  // RCL_MICROROS
 #include "rcl/context.h"
 #include "rcl/guard_condition.h"
 #include "rcl/macros.h"
diff --git a/rcl/include/rcl/node_options.h b/rcl/include/rcl/node_options.h
index 140749f49..8380776be 100644
--- a/rcl/include/rcl/node_options.h
+++ b/rcl/include/rcl/node_options.h
@@ -23,9 +23,11 @@ extern "C"
 #endif
 
 #include "rcl/allocator.h"
+#ifndef RCL_MICROROS
 #include "rcl/arguments.h"
-
+#endif  // RCL_MICROROS
 #include "rcl/domain_id.h"
+#include "rcl/macros.h"
 
 /// Constant which indicates that the default domain id should be used.
 #define RCL_NODE_OPTIONS_DEFAULT_DOMAIN_ID RCL_DEFAULT_DOMAIN_ID
@@ -46,8 +48,10 @@ typedef struct rcl_node_options_s
   /// If false then only use arguments in this struct, otherwise use global arguments also.
   bool use_global_arguments;
 
+#ifndef RCL_MICROROS
   /// Command line arguments that apply only to this node.
   rcl_arguments_t arguments;
+#endif  // RCL_MICROROS
 
   /// Flag to enable rosout for this node
   bool enable_rosout;
diff --git a/rcl/src/rcl/arguments_impl.h b/rcl/src/rcl/arguments_impl.h
index e8d73b585..0cc965a06 100644
--- a/rcl/src/rcl/arguments_impl.h
+++ b/rcl/src/rcl/arguments_impl.h
@@ -17,7 +17,11 @@
 
 #include "rcl/arguments.h"
 #include "rcl/log_level.h"
+#ifndef RCL_MICROROS
 #include "rcl_yaml_param_parser/types.h"
+#else
+typedef bool rcl_params_t;
+#endif  // RCL_MICROROS
 #include "./remap_impl.h"
 
 #ifdef __cplusplus
diff --git a/rcl/src/rcl/client.c b/rcl/src/rcl/client.c
index 7529c783d..7b632ccf0 100644
--- a/rcl/src/rcl/client.c
+++ b/rcl/src/rcl/client.c
@@ -24,7 +24,9 @@ extern "C"
 
 #include "rcl/error_handling.h"
 #include "rcl/node.h"
+#ifndef RCL_MICROROS
 #include "rcl/node_type_cache.h"
+#endif  // RCL_MICROROS
 #include "rcl/publisher.h"
 #include "rcl/time.h"
 #include "rcutils/logging_macros.h"
@@ -169,6 +171,7 @@ rcl_client_init(
   atomic_init(&client->impl->sequence_number, 0);
   client->impl->in_use_by_waitset = false;
 
+#ifndef RCL_MICROROS
   const rosidl_type_hash_t * hash = type_support->get_type_hash_func(type_support);
   if (hash == NULL) {
     RCL_SET_ERROR_MSG("Failed to get the type hash");
@@ -186,6 +189,7 @@ rcl_client_init(
     goto destroy_client;
   }
   client->impl->type_hash = *hash;
+#endif  // RCL_MICROROS
 
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Client initialized");
   TRACETOOLS_TRACEPOINT(
@@ -248,6 +252,7 @@ rcl_client_fini(rcl_client_t * client, rcl_node_t * node)
       result = RCL_RET_ERROR;
     }
 
+#ifndef RCL_MICROROS
     if (
       ROSIDL_TYPE_HASH_VERSION_UNSET != client->impl->type_hash.version &&
       RCL_RET_OK != rcl_node_type_cache_unregister_type(node, &client->impl->type_hash))
@@ -255,6 +260,7 @@ rcl_client_fini(rcl_client_t * client, rcl_node_t * node)
       RCUTILS_SAFE_FWRITE_TO_STDERR(rcl_get_error_string().str);
       result = RCL_RET_ERROR;
     }
+#endif  // RCL_MICROROS
 
     allocator.deallocate(client->impl->remapped_service_name, allocator.state);
     client->impl->remapped_service_name = NULL;
diff --git a/rcl/src/rcl/context.c b/rcl/src/rcl/context.c
index 7f7d37144..f372bcbca 100644
--- a/rcl/src/rcl/context.c
+++ b/rcl/src/rcl/context.c
@@ -32,6 +32,7 @@ rcl_get_zero_initialized_context(void)
     .impl = NULL,
     .instance_id_storage = {0},
   };
+#ifndef RCL_MICROROS
   // this is not constexpr so it cannot be in the struct initialization
   context.global_arguments = rcl_get_zero_initialized_arguments();
   // ensure assumption about static storage
@@ -40,6 +41,7 @@ rcl_get_zero_initialized_context(void)
     "expected rcl_context_t's instance id storage to be >= size of atomic_uint_least64_t");
   // initialize atomic
   atomic_init((atomic_uint_least64_t *)(&context.instance_id_storage), 0);
+#endif  // RCL_MICROROS
   return context;
 }
 
@@ -76,7 +78,11 @@ rcl_context_instance_id_t
 rcl_context_get_instance_id(const rcl_context_t * context)
 {
   RCL_CHECK_ARGUMENT_FOR_NULL(context, 0);
+#ifdef RCL_MICROROS
+  return context->instance_id_storage;
+#else
   return rcutils_atomic_load_uint64_t((atomic_uint_least64_t *)(&context->instance_id_storage));
+#endif  // RCL_MICROROS
 }
 
 rcl_ret_t
@@ -110,8 +116,13 @@ __cleanup_context(rcl_context_t * context)
 {
   rcl_ret_t ret = RCL_RET_OK;
   // reset the instance id to 0 to indicate "invalid" (should already be 0, but this is defensive)
+#ifdef RCL_MICROROS
+  context->instance_id_storage = 0;
+#else
   rcutils_atomic_store((atomic_uint_least64_t *)(&context->instance_id_storage), 0);
+#endif  // RCL_MICROROS
 
+#ifndef RCL_MICROROS
   // clean up global_arguments if initialized
   if (NULL != context->global_arguments.impl) {
     ret = rcl_arguments_fini(&(context->global_arguments));
@@ -124,6 +135,7 @@ __cleanup_context(rcl_context_t * context)
       rcl_reset_error();
     }
   }
+#endif  // RCL_MICROROS
 
   // if impl is null, nothing else can be cleaned up
   if (NULL != context->impl) {
diff --git a/rcl/src/rcl/init.c b/rcl/src/rcl/init.c
index ef54321a4..cd92fcef6 100644
--- a/rcl/src/rcl/init.c
+++ b/rcl/src/rcl/init.c
@@ -27,20 +27,28 @@ extern "C"
 
 #include "tracetools/tracetools.h"
 
+#ifndef RCL_MICROROS
 #include "rcl/arguments.h"
+#endif  // RCL_MICROROS
 #include "rcl/discovery_options.h"
 #include "rcl/domain_id.h"
 #include "rcl/error_handling.h"
+#ifndef RCL_MICROROS
 #include "rcl/logging.h"
+#endif  // RCL_MICROROS
 #include "rcl/security.h"
 #include "rcl/validate_enclave_name.h"
 
+#ifndef RCL_MICROROS
 #include "./arguments_impl.h"
+#endif  // RCL_MICROROS
 #include "./common.h"
 #include "./context_impl.h"
 #include "./init_options_impl.h"
 
+#ifndef RCL_MICROROS
 static atomic_uint_least64_t __rcl_next_unique_id = ATOMIC_VAR_INIT(1);
+#endif  // RCL_MICROROS
 
 rcl_ret_t
 rcl_init(
@@ -81,8 +89,10 @@ rcl_init(
     return RCL_RET_ALREADY_INIT;
   }
 
+#ifndef RCL_MICROROS
   // Zero initialize global arguments.
   context->global_arguments = rcl_get_zero_initialized_arguments();
+#endif  // RCL_MICROROS
 
   // Setup impl for context.
   // use zero_allocate so the cleanup function will not try to clean up uninitialized parts later
@@ -124,6 +134,7 @@ rcl_init(
     }
   }
 
+#ifndef RCL_MICROROS
   // Parse the ROS specific arguments.
   ret = rcl_parse_arguments(argc, argv, allocator, &context->global_arguments);
   if (RCL_RET_OK != ret) {
@@ -131,7 +142,9 @@ rcl_init(
     RCUTILS_LOG_ERROR_NAMED(ROS_PACKAGE_NAME, "Failed to parse global arguments");
     goto fail;
   }
+#endif  // RCL_MICROROS
 
+#ifndef RCL_MICROROS
   // Set the instance id.
   uint64_t next_instance_id = rcutils_atomic_fetch_add_uint64_t(&__rcl_next_unique_id, 1);
   if (0 == next_instance_id) {
@@ -141,7 +154,13 @@ rcl_init(
     rcutils_atomic_store(&__rcl_next_unique_id, -1);
     goto fail;
   }
+#endif  // RCL_MICROROS
+#ifdef RCL_MICROROS
+  static uint32_t next_instance_id = 1;
+  context->instance_id_storage = next_instance_id;
+#else
   rcutils_atomic_store((atomic_uint_least64_t *)(&context->instance_id_storage), next_instance_id);
+#endif  // RCL_MICROROS
   context->impl->init_options.impl->rmw_init_options.instance_id = next_instance_id;
 
   size_t * domain_id = &context->impl->init_options.impl->rmw_init_options.domain_id;
@@ -214,6 +233,7 @@ rcl_init(
       "\t%s", discovery_options->static_peers[ii].peer_address);
   }
 
+#ifndef RCL_MICROROS
   if (context->global_arguments.impl->enclave) {
     context->impl->init_options.impl->rmw_init_options.enclave = rcutils_strdup(
       context->global_arguments.impl->enclave,
@@ -259,6 +279,7 @@ rcl_init(
     fail_ret = ret;
     goto fail;
   }
+#endif  // RCL_MICROROS
 
   // Initialize rmw_init.
   rmw_ret_t rmw_ret = rmw_init(
@@ -299,7 +320,11 @@ rcl_shutdown(rcl_context_t * context)
   }
 
   // reset the instance id to 0 to indicate "invalid"
+#ifdef RCL_MICROROS
+  context->instance_id_storage = 0;
+#else
   rcutils_atomic_store((atomic_uint_least64_t *)(&context->instance_id_storage), 0);
+#endif  // RCL_MICROROS
 
   return RCL_RET_OK;
 }
diff --git a/rcl/src/rcl/node.c b/rcl/src/rcl/node.c
index c1d286a26..f22d22338 100644
--- a/rcl/src/rcl/node.c
+++ b/rcl/src/rcl/node.c
@@ -19,12 +19,16 @@
 #include <stdlib.h>
 #include <string.h>
 
+#ifndef RCL_MICROROS
 #include "rcl/arguments.h"
+#endif  // RCL_MICROROS
 #include "rcl/error_handling.h"
 #include "rcl/init_options.h"
+#ifndef RCL_MICROROS
 #include "rcl/logging.h"
 #include "rcl/logging_rosout.h"
 #include "rcl/node_type_cache.h"
+#endif  // RCL_MICROROS
 #include "rcl/rcl.h"
 #include "rcl/remap.h"
 #include "rcl/security.h"
@@ -190,7 +194,9 @@ rcl_node_init(
   RCL_CHECK_FOR_NULL_WITH_MSG(
     node->impl, "allocating memory failed", ret = RCL_RET_BAD_ALLOC; goto fail);
   node->impl->options = rcl_node_get_default_options();
+#ifndef RCL_MICROROS
   node->impl->registered_types_by_type_hash = rcutils_get_zero_initialized_hash_map();
+#endif  // RCL_MICROROS
   node->context = context;
   // Initialize node impl.
   ret = rcl_node_options_copy(options, &(node->impl->options));
@@ -198,6 +204,7 @@ rcl_node_init(
     goto fail;
   }
 
+#ifndef RCL_MICROROS
   // Remap the node name and namespace if remap rules are given
   rcl_arguments_t * global_args = NULL;
   if (node->impl->options.use_global_arguments) {
@@ -224,6 +231,7 @@ rcl_node_init(
     allocator->deallocate((char *)local_namespace_, allocator->state);
     local_namespace_ = remapped_namespace;
   }
+#endif  // RCL_MICROROS
 
   // compute fully qualfied name of the node.
   if ('/' == local_namespace_[strlen(local_namespace_) - 1]) {
@@ -236,9 +244,11 @@ rcl_node_init(
     ret = RCL_RET_BAD_ALLOC; goto fail);
 
   // node logger name
+#ifndef RCL_MICROROS
   node->impl->logger_name = rcl_create_node_logger_name(name, local_namespace_, allocator);
   RCL_CHECK_FOR_NULL_WITH_MSG(
     node->impl->logger_name, "creating logger name failed", ret = RCL_RET_ERROR; goto fail);
+#endif  // RCL_MICROROS
 
   RCUTILS_LOG_DEBUG_NAMED(
     ROS_PACKAGE_NAME, "Using domain ID of '%zu'", context->impl->rmw_context.actual_domain_id);
@@ -279,12 +289,14 @@ rcl_node_init(
     goto fail;
   }
 
+#ifndef RCL_MICROROS
   // To capture all types from builtin topics and services, the type cache needs to be initialized
   // before any publishers/subscriptions/services/etc can be created
   ret = rcl_node_type_cache_init(node);
   if (ret != RCL_RET_OK) {
     goto fail;
   }
+#endif  // RCL_MICROROS
 
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Node initialized");
   TRACETOOLS_TRACEPOINT(
@@ -301,12 +313,14 @@ rcl_node_init(
 
 fail:
   if (node->impl) {
+#ifndef RCL_MICROROS
     if (NULL != node->impl->registered_types_by_type_hash.impl) {
       fail_ret = rcl_node_type_cache_fini(node);
       RCUTILS_LOG_ERROR_EXPRESSION_NAMED(
         (fail_ret != RCL_RET_OK),
         ROS_PACKAGE_NAME, "Failed to fini type cache for node: %s", rcl_get_error_string().str);
     }
+#endif  // RCL_MICROROS
 
     if (node->impl->graph_guard_condition) {
       fail_ret = rcl_guard_condition_fini(node->impl->graph_guard_condition);
@@ -357,11 +371,13 @@ rcl_node_fini(rcl_node_t * node)
   rcl_allocator_t allocator = node->impl->options.allocator;
   rcl_ret_t result = RCL_RET_OK;
   rcl_ret_t rcl_ret = RCL_RET_OK;
+#ifndef RCL_MICROROS
   rcl_ret = rcl_node_type_cache_fini(node);
   if (rcl_ret != RCL_RET_OK) {
     RCL_SET_ERROR_MSG("Unable to fini type cache for node.");
     result = RCL_RET_ERROR;
   }
+#endif  // RCL_MICROROS
   rmw_ret_t rmw_ret = rmw_destroy_node(node->impl->rmw_node_handle);
   if (rmw_ret != RMW_RET_OK) {
     RCL_SET_ERROR_MSG(rmw_get_error_string().str);
@@ -376,12 +392,14 @@ rcl_node_fini(rcl_node_t * node)
   // assuming that allocate and deallocate are ok since they are checked in init
   allocator.deallocate((char *)node->impl->logger_name, allocator.state);
   allocator.deallocate((char *)node->impl->fq_name, allocator.state);
+#ifndef RCL_MICROROS
   if (NULL != node->impl->options.arguments.impl) {
     rcl_ret_t ret = rcl_arguments_fini(&(node->impl->options.arguments));
     if (ret != RCL_RET_OK) {
       return ret;
     }
   }
+#endif  // RCL_MICROROS
   allocator.deallocate(node->impl, allocator.state);
   node->impl = NULL;
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Node finalized");
@@ -524,6 +542,7 @@ void rcl_node_type_description_service_handle_request(
   const type_description_interfaces__srv__GetTypeDescription_Request * request,
   type_description_interfaces__srv__GetTypeDescription_Response * response)
 {
+#ifndef RCL_MICROROS
   rcl_type_info_t type_info;
   RCL_CHECK_FOR_NULL_WITH_MSG(node, "invalid node handle", return;);
   RCL_CHECK_FOR_NULL_WITH_MSG(node->impl, "invalid node", return;);
@@ -582,12 +601,14 @@ void rcl_node_type_description_service_handle_request(
   }
 
   response->successful = true;
+#endif  // RCL_MICROROS
 }
 
 rcl_ret_t rcl_node_type_description_service_init(
   rcl_service_t * service,
   const rcl_node_t * node)
 {
+#ifndef RCL_MICROROS
   RCL_CHECK_ARGUMENT_FOR_NULL(service, RCL_RET_INVALID_ARGUMENT);
   RCL_CHECK_ARGUMENT_FOR_NULL(node, RCL_RET_INVALID_ARGUMENT);
   RCL_CHECK_ARGUMENT_FOR_NULL(node->impl, RCL_RET_NODE_INVALID);
@@ -622,4 +643,8 @@ rcl_ret_t rcl_node_type_description_service_init(
   allocator.deallocate(service_name, allocator.state);
 
   return ret;
+#else
+  (void)node;
+  return RCL_RET_UNSUPPORTED;
+#endif  // RCL_MICROROS
 }
diff --git a/rcl/src/rcl/node_impl.h b/rcl/src/rcl/node_impl.h
index 5445c5aab..3641e618b 100644
--- a/rcl/src/rcl/node_impl.h
+++ b/rcl/src/rcl/node_impl.h
@@ -30,7 +30,9 @@ struct rcl_node_impl_s
   rcl_guard_condition_t * graph_guard_condition;
   const char * logger_name;
   const char * fq_name;
+#ifndef RCL_MICROROS
   rcutils_hash_map_t registered_types_by_type_hash;
+#endif  // RCL_MICROROS
 };
 
 #endif  // RCL__NODE_IMPL_H_
diff --git a/rcl/src/rcl/node_options.c b/rcl/src/rcl/node_options.c
index 311824bbf..fca69b283 100644
--- a/rcl/src/rcl/node_options.c
+++ b/rcl/src/rcl/node_options.c
@@ -21,10 +21,14 @@ extern "C"
 
 #include "rcl/node_options.h"
 
+#ifndef RCL_MICROROS
 #include "rcl/arguments.h"
+#endif  // RCL_MICROROS
 #include "rcl/domain_id.h"
 #include "rcl/error_handling.h"
+#ifndef RCL_MICROROS
 #include "rcl/logging_rosout.h"
+#endif  // RCL_MICROROS
 
 #include "rmw/qos_profiles.h"
 
@@ -35,9 +39,13 @@ rcl_node_get_default_options(void)
   rcl_node_options_t default_options = {
     .allocator = rcl_get_default_allocator(),
     .use_global_arguments = true,
+  #ifndef RCL_MICROROS
     .arguments = rcl_get_zero_initialized_arguments(),
     .enable_rosout = true,
     .rosout_qos = rmw_qos_profile_rosout_default,
+  #else
+    .enable_rosout = false,
+  #endif  // RCL_MICROROS
   };
   return default_options;
 }
@@ -55,17 +63,21 @@ rcl_node_options_copy(
     RCL_SET_ERROR_MSG("Attempted to copy options into itself");
     return RCL_RET_INVALID_ARGUMENT;
   }
+#ifndef RCL_MICROROS
   if (NULL != options_out->arguments.impl) {
     RCL_SET_ERROR_MSG("Options out must be zero initialized");
     return RCL_RET_INVALID_ARGUMENT;
   }
+#endif  // RCL_MICROROS
   options_out->allocator = options->allocator;
   options_out->use_global_arguments = options->use_global_arguments;
   options_out->enable_rosout = options->enable_rosout;
   options_out->rosout_qos = options->rosout_qos;
+#ifndef RCL_MICROROS
   if (NULL != options->arguments.impl) {
     return rcl_arguments_copy(&(options->arguments), &(options_out->arguments));
   }
+#endif  // RCL_MICROROS
   return RCL_RET_OK;
 }
 
@@ -77,6 +89,7 @@ rcl_node_options_fini(
   rcl_allocator_t allocator = options->allocator;
   RCL_CHECK_ALLOCATOR(&allocator, return RCL_RET_INVALID_ARGUMENT);
 
+#ifndef RCL_MICROROS
   if (options->arguments.impl) {
     rcl_ret_t ret = rcl_arguments_fini(&options->arguments);
     if (RCL_RET_OK != ret) {
@@ -84,6 +97,7 @@ rcl_node_options_fini(
       return ret;
     }
   }
+#endif  // RCL_MICROROS
 
   return RCL_RET_OK;
 }
diff --git a/rcl/src/rcl/node_resolve_name.c b/rcl/src/rcl/node_resolve_name.c
index c3b60317f..cd04c7e90 100644
--- a/rcl/src/rcl/node_resolve_name.c
+++ b/rcl/src/rcl/node_resolve_name.c
@@ -75,6 +75,7 @@ rcl_resolve_name(
     goto cleanup;
   }
   // remap topic name
+#ifndef RCL_MICROROS
   if (!only_expand) {
     ret = rcl_remap_name(
       local_args, global_args, is_service ? RCL_SERVICE_REMAP : RCL_TOPIC_REMAP,
@@ -84,6 +85,7 @@ rcl_resolve_name(
       goto cleanup;
     }
   }
+#endif  // RCL_MICROROS
   if (NULL == remapped_topic_name) {
     remapped_topic_name = expanded_topic_name;
     expanded_topic_name = NULL;
@@ -145,12 +147,18 @@ rcl_node_resolve_name(
     return RCL_RET_ERROR;
   }
   rcl_arguments_t * global_args = NULL;
+#ifndef RCL_MICROROS
   if (node_options->use_global_arguments) {
     global_args = &(node->context->global_arguments);
   }
+#endif  // RCL_MICROROS
 
   return rcl_resolve_name(
+#ifndef RCL_MICROROS
     &(node_options->arguments),
+#else
+    NULL,
+#endif  // RCL_MICROROS
     global_args,
     input_topic_name,
     rcl_node_get_name(node),
diff --git a/rcl/src/rcl/publisher.c b/rcl/src/rcl/publisher.c
index 99067ccd3..98b2555f5 100644
--- a/rcl/src/rcl/publisher.c
+++ b/rcl/src/rcl/publisher.c
@@ -22,7 +22,9 @@ extern "C"
 #include "rcl/allocator.h"
 #include "rcl/error_handling.h"
 #include "rcl/node.h"
+#ifndef RCL_MICROROS
 #include "rcl/node_type_cache.h"
+#endif  // RCL_MICROROS
 #include "rcutils/logging_macros.h"
 #include "rcutils/macros.h"
 #include "rcl/time.h"
@@ -127,6 +129,7 @@ rcl_publisher_init(
   // options
   publisher->impl->options = *options;
 
+#ifndef RCL_MICROROS
   if (RCL_RET_OK != rcl_node_type_cache_register_type(
       node, type_support->get_type_hash_func(type_support),
       type_support->get_type_description_func(type_support),
@@ -137,6 +140,7 @@ rcl_publisher_init(
     goto fail;
   }
   publisher->impl->type_hash = *type_support->get_type_hash_func(type_support);
+#endif  // RCL_MICROROS
 
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Publisher initialized");
   // context
@@ -199,6 +203,7 @@ rcl_publisher_fini(rcl_publisher_t * publisher, rcl_node_t * node)
       RCL_SET_ERROR_MSG(rmw_get_error_string().str);
       result = RCL_RET_ERROR;
     }
+#ifndef RCL_MICROROS
     if (
       ROSIDL_TYPE_HASH_VERSION_UNSET != publisher->impl->type_hash.version &&
       RCL_RET_OK != rcl_node_type_cache_unregister_type(node, &publisher->impl->type_hash))
@@ -206,6 +211,7 @@ rcl_publisher_fini(rcl_publisher_t * publisher, rcl_node_t * node)
       RCUTILS_SAFE_FWRITE_TO_STDERR(rcl_get_error_string().str);
       result = RCL_RET_ERROR;
     }
+#endif  // RCL_MICROROS
     allocator.deallocate(publisher->impl, allocator.state);
     publisher->impl = NULL;
   }
diff --git a/rcl/src/rcl/publisher_impl.h b/rcl/src/rcl/publisher_impl.h
index f7e87c046..f44c31581 100644
--- a/rcl/src/rcl/publisher_impl.h
+++ b/rcl/src/rcl/publisher_impl.h
@@ -24,7 +24,9 @@ struct rcl_publisher_impl_s
   rmw_qos_profile_t actual_qos;
   rcl_context_t * context;
   rmw_publisher_t * rmw_handle;
+#ifndef RCL_MICROROS
   rosidl_type_hash_t type_hash;
+#endif  // RCL_MICROROS
 };
 
 #endif  // RCL__PUBLISHER_IMPL_H_
diff --git a/rcl/src/rcl/service.c b/rcl/src/rcl/service.c
index 97816a54d..b50b1663f 100644
--- a/rcl/src/rcl/service.c
+++ b/rcl/src/rcl/service.c
@@ -24,7 +24,9 @@ extern "C"
 
 #include "rcl/error_handling.h"
 #include "rcl/node.h"
+#ifndef RCL_MICROROS
 #include "rcl/node_type_cache.h"
+#endif  // RCL_MICROROS
 #include "rcl/publisher.h"
 #include "rcl/time.h"
 #include "rcl/types.h"
@@ -181,6 +183,7 @@ rcl_service_init(
   service->impl->options = *options;
   service->impl->in_use_by_waitset = false;
 
+#ifndef RCL_MICROROS
   if (RCL_RET_OK != rcl_node_type_cache_register_type(
       node, type_support->get_type_hash_func(type_support),
       type_support->get_type_description_func(type_support),
@@ -192,6 +195,7 @@ rcl_service_init(
     goto destroy_service;
   }
   service->impl->type_hash = *type_support->get_type_hash_func(type_support);
+#endif  // RCL_MICROROS
 
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Service initialized");
   TRACETOOLS_TRACEPOINT(
@@ -255,6 +259,7 @@ rcl_service_fini(rcl_service_t * service, rcl_node_t * node)
       result = RCL_RET_ERROR;
     }
 
+#ifndef RCL_MICROROS
     if (
       ROSIDL_TYPE_HASH_VERSION_UNSET != service->impl->type_hash.version &&
       RCL_RET_OK != rcl_node_type_cache_unregister_type(node, &service->impl->type_hash))
@@ -262,6 +267,7 @@ rcl_service_fini(rcl_service_t * service, rcl_node_t * node)
       RCUTILS_SAFE_FWRITE_TO_STDERR(rcl_get_error_string().str);
       result = RCL_RET_ERROR;
     }
+#endif  // RCL_MICROROS
 
     allocator.deallocate(service->impl->remapped_service_name, allocator.state);
     service->impl->remapped_service_name = NULL;
diff --git a/rcl/src/rcl/subscription.c b/rcl/src/rcl/subscription.c
index 2e36cbb6e..5da2933e4 100644
--- a/rcl/src/rcl/subscription.c
+++ b/rcl/src/rcl/subscription.c
@@ -23,8 +23,10 @@ extern "C"
 
 #include "rcl/error_handling.h"
 #include "rcl/node.h"
+#ifndef RCL_MICROROS
 #include "rcl/node_type_cache.h"
 #include "rcutils/env.h"
+#endif  // RCL_MICROROS
 #include "rcutils/logging_macros.h"
 #include "rcutils/strdup.h"
 #include "rcutils/types/string_array.h"
@@ -128,6 +130,7 @@ rcl_subscription_init(
   subscription->impl->actual_qos.avoid_ros_namespace_conventions =
     options->qos.avoid_ros_namespace_conventions;
 
+#ifndef RCL_MICROROS
   if (RCL_RET_OK != rcl_node_type_cache_register_type(
       node, type_support->get_type_hash_func(type_support),
       type_support->get_type_description_func(type_support),
@@ -138,6 +141,7 @@ rcl_subscription_init(
     goto fail;
   }
   subscription->impl->type_hash = *type_support->get_type_hash_func(type_support);
+#endif  // RCL_MICROROS
 
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Subscription initialized");
   ret = RCL_RET_OK;
@@ -210,6 +214,7 @@ rcl_subscription_fini(rcl_subscription_t * subscription, rcl_node_t * node)
       result = RCL_RET_ERROR;
     }
 
+#ifndef RCL_MICROROS
     if (
       ROSIDL_TYPE_HASH_VERSION_UNSET != subscription->impl->type_hash.version &&
       RCL_RET_OK != rcl_node_type_cache_unregister_type(node, &subscription->impl->type_hash))
@@ -218,6 +223,7 @@ rcl_subscription_fini(rcl_subscription_t * subscription, rcl_node_t * node)
       RCUTILS_SAFE_FWRITE_TO_STDERR("\n");
       result = RCL_RET_ERROR;
     }
+#endif  // RCL_MICROROS
 
     allocator.deallocate(subscription->impl, allocator.state);
     subscription->impl = NULL;
@@ -236,6 +242,7 @@ rcl_subscription_get_default_options(void)
   default_options.allocator = rcl_get_default_allocator();
   default_options.rmw_subscription_options = rmw_get_default_subscription_options();
 
+#ifndef RCL_MICROROS
   // Load disable flag to LoanedMessage via environmental variable.
   // TODO(clalancette): This is kind of a copy of rcl_get_disable_loaned_message(), but we need
   // more information than that function provides.
@@ -251,6 +258,7 @@ rcl_subscription_get_default_options(void)
   } else {
     default_options.disable_loaned_message = !(strcmp(env_val, "0") == 0);
   }
+#endif  // RCL_MICROROS
 
   return default_options;
 }
diff --git a/rcl/src/rcl/subscription_impl.h b/rcl/src/rcl/subscription_impl.h
index 7af04ed9b..ffe30e7eb 100644
--- a/rcl/src/rcl/subscription_impl.h
+++ b/rcl/src/rcl/subscription_impl.h
@@ -24,7 +24,9 @@ struct rcl_subscription_impl_s
   rcl_subscription_options_t options;
   rmw_qos_profile_t actual_qos;
   rmw_subscription_t * rmw_handle;
+#ifndef RCL_MICROROS
   rosidl_type_hash_t type_hash;
+#endif  // RCL_MICROROS
   bool in_use_by_waitset;
 };
 
diff --git a/rcl/src/rcl/type_hash.c b/rcl/src/rcl/type_hash.c
index 8c6b217d8..d52164a0e 100644
--- a/rcl/src/rcl/type_hash.c
+++ b/rcl/src/rcl/type_hash.c
@@ -14,7 +14,9 @@
 
 #include <stdio.h>
 
+#ifndef RCL_MICROROS
 #include <yaml.h>
+#endif  // RCL_MICROROS
 
 #include "rcl/allocator.h"
 #include "rcl/error_handling.h"
@@ -25,6 +27,7 @@
 
 #include "./common.h"
 
+#ifndef RCL_MICROROS
 static int yaml_write_handler(void * ext, uint8_t * buffer, size_t size)
 {
   rcutils_char_array_t * repr = (rcutils_char_array_t *)ext;
@@ -193,12 +196,14 @@ static int emit_type_description(
   }
   return end_sequence(emitter) && end_mapping(emitter);
 }
+#endif  // RCL_MICROROS
 
 rcl_ret_t
 rcl_type_description_to_hashable_json(
   const type_description_interfaces__msg__TypeDescription * type_description,
   rcutils_char_array_t * output_repr)
 {
+#ifndef RCL_MICROROS
   RCL_CHECK_ARGUMENT_FOR_NULL(type_description, RCL_RET_INVALID_ARGUMENT);
   RCL_CHECK_ARGUMENT_FOR_NULL(output_repr, RCL_RET_INVALID_ARGUMENT);
 
@@ -240,6 +245,11 @@ rcl_type_description_to_hashable_json(
   rcl_set_error_state(emitter.problem, __FILE__, __LINE__);
   yaml_emitter_delete(&emitter);
   return RCL_RET_ERROR;
+#else
+  (void)type_description;
+  (void)output_repr;
+  return RCL_RET_UNSUPPORTED;
+#endif  // RCL_MICROROS
 }
 
 rcl_ret_t
@@ -247,6 +257,7 @@ rcl_calculate_type_hash(
   const type_description_interfaces__msg__TypeDescription * type_description,
   rosidl_type_hash_t * output_hash)
 {
+#ifndef RCL_MICROROS
   RCL_CHECK_ARGUMENT_FOR_NULL(type_description, RCL_RET_INVALID_ARGUMENT);
   RCL_CHECK_ARGUMENT_FOR_NULL(output_hash, RCL_RET_INVALID_ARGUMENT);
 
@@ -270,4 +281,9 @@ rcl_calculate_type_hash(
   }
   result = rcutils_char_array_fini(&msg_repr);
   return result;
+#else
+  (void)type_description;
+  (void)output_hash;
+  return RCL_RET_UNSUPPORTED;
+#endif  // RCL_MICROROS
 }
diff --git a/rcl_action/src/rcl_action/action_client.c b/rcl_action/src/rcl_action/action_client.c
index df4cbff30..f94978cef 100644
--- a/rcl_action/src/rcl_action/action_client.c
+++ b/rcl_action/src/rcl_action/action_client.c
@@ -28,7 +28,9 @@ extern "C"
 #include "rcl/client.h"
 #include "rcl/error_handling.h"
 #include "rcl/graph.h"
+#ifndef RCL_MICROROS
 #include "rcl/node_type_cache.h"
+#endif  // RCL_MICROROS
 #include "rcl/subscription.h"
 #include "rcl/types.h"
 #include "rcl/wait.h"
@@ -66,7 +68,9 @@ _rcl_action_get_zero_initialized_client_impl(void)
     0,
     0,
     0,
+#ifndef RCL_MICROROS
     rosidl_get_zero_initialized_type_hash(),
+#endif  // RCL_MICROROS
     false
   };
   return null_action_client;
@@ -95,12 +99,14 @@ _rcl_action_client_fini_impl(
   if (RCL_RET_OK != rcl_subscription_fini(&action_client->impl->status_subscription, node)) {
     ret = RCL_RET_ERROR;
   }
+#ifndef RCL_MICROROS
   if (
     ROSIDL_TYPE_HASH_VERSION_UNSET != action_client->impl->type_hash.version &&
     RCL_RET_OK != rcl_node_type_cache_unregister_type(node, &action_client->impl->type_hash))
   {
     ret = RCL_RET_ERROR;
   }
+#endif  // RCL_MICROROS
   allocator.deallocate(action_client->impl->remapped_action_name, allocator.state);
   allocator.deallocate(action_client->impl, allocator.state);
   action_client->impl = NULL;
@@ -234,16 +240,18 @@ rcl_action_client_init(
   SUBSCRIPTION_INIT(feedback);
   SUBSCRIPTION_INIT(status);
 
+#ifndef RCL_MICROROS
   ret = rcl_node_type_cache_register_type(
-      node, type_support->get_type_hash_func(type_support),
-      type_support->get_type_description_func(type_support),
-      type_support->get_type_description_sources_func(type_support));
+    node, type_support->get_type_hash_func(type_support),
+    type_support->get_type_description_func(type_support),
+    type_support->get_type_description_sources_func(type_support));
   if (RCL_RET_OK != ret) {
     rcutils_reset_error();
     RCL_SET_ERROR_MSG("Failed to register type for action");
     goto fail;
   }
   action_client->impl->type_hash = *type_support->get_type_hash_func(type_support);
+#endif  // RCL_MICROROS
 
   RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Action client initialized");
   return ret;
@@ -341,41 +349,41 @@ rcl_action_server_is_available(
 
 // \internal Sends an action client specific service request.
 #define SEND_SERVICE_REQUEST(Type, request, sequence_number) \
-  RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Sending action " #Type " request"); \
-  if (!rcl_action_client_is_valid(action_client)) { \
-    return RCL_RET_ACTION_CLIENT_INVALID;  /* error already set */ \
-  } \
-  RCL_CHECK_ARGUMENT_FOR_NULL(request, RCL_RET_INVALID_ARGUMENT); \
-  RCL_CHECK_ARGUMENT_FOR_NULL(sequence_number, RCL_RET_INVALID_ARGUMENT); \
-  rcl_ret_t ret = rcl_send_request( \
-    &action_client->impl->Type ## _client, request, sequence_number); \
-  if (RCL_RET_OK != ret) { \
-    return RCL_RET_ERROR;  /* error already set */ \
-  } \
-  RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Action " #Type " request sent"); \
-  return RCL_RET_OK;
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Sending action " #Type " request"); \
+        if (!rcl_action_client_is_valid(action_client)) { \
+          return RCL_RET_ACTION_CLIENT_INVALID; /* error already set */ \
+        } \
+        RCL_CHECK_ARGUMENT_FOR_NULL(request, RCL_RET_INVALID_ARGUMENT); \
+        RCL_CHECK_ARGUMENT_FOR_NULL(sequence_number, RCL_RET_INVALID_ARGUMENT); \
+        rcl_ret_t ret = rcl_send_request( \
+          &action_client->impl->Type ## _client, request, sequence_number); \
+        if (RCL_RET_OK != ret) { \
+          return RCL_RET_ERROR; /* error already set */ \
+        } \
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Action " #Type " request sent"); \
+        return RCL_RET_OK;
 
 // \internal Takes an action client specific service response.
 #define TAKE_SERVICE_RESPONSE(Type, response_header, response) \
-  RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Taking action " #Type " response"); \
-  if (!rcl_action_client_is_valid(action_client)) { \
-    return RCL_RET_ACTION_CLIENT_INVALID;  /* error already set */ \
-  } \
-  RCL_CHECK_ARGUMENT_FOR_NULL(response_header, RCL_RET_INVALID_ARGUMENT); \
-  RCL_CHECK_ARGUMENT_FOR_NULL(response, RCL_RET_INVALID_ARGUMENT); \
-  rcl_ret_t ret = rcl_take_response( \
-    &action_client->impl->Type ## _client, response_header, response); \
-  if (RCL_RET_OK != ret) { \
-    if (RCL_RET_BAD_ALLOC == ret) { \
-      return RCL_RET_BAD_ALLOC;  /* error already set */ \
-    } \
-    if (RCL_RET_CLIENT_TAKE_FAILED == ret) { \
-      return RCL_RET_ACTION_CLIENT_TAKE_FAILED; \
-    } \
-    return RCL_RET_ERROR;  /* error already set */ \
-  } \
-  RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Action " #Type " response taken"); \
-  return RCL_RET_OK;
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Taking action " #Type " response"); \
+        if (!rcl_action_client_is_valid(action_client)) { \
+          return RCL_RET_ACTION_CLIENT_INVALID; /* error already set */ \
+        } \
+        RCL_CHECK_ARGUMENT_FOR_NULL(response_header, RCL_RET_INVALID_ARGUMENT); \
+        RCL_CHECK_ARGUMENT_FOR_NULL(response, RCL_RET_INVALID_ARGUMENT); \
+        rcl_ret_t ret = rcl_take_response( \
+          &action_client->impl->Type ## _client, response_header, response); \
+        if (RCL_RET_OK != ret) { \
+          if (RCL_RET_BAD_ALLOC == ret) { \
+            return RCL_RET_BAD_ALLOC; /* error already set */ \
+          } \
+          if (RCL_RET_CLIENT_TAKE_FAILED == ret) { \
+            return RCL_RET_ACTION_CLIENT_TAKE_FAILED; \
+          } \
+          return RCL_RET_ERROR; /* error already set */ \
+        } \
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Action " #Type " response taken"); \
+        return RCL_RET_OK;
 
 
 rcl_ret_t
@@ -434,25 +442,25 @@ rcl_action_take_cancel_response(
 
 // \internal Takes an action client specific topic message.
 #define TAKE_MESSAGE(Type) \
-  RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Taking action " #Type); \
-  if (!rcl_action_client_is_valid(action_client)) { \
-    return RCL_RET_ACTION_CLIENT_INVALID;  /* error already set */ \
-  } \
-  RCL_CHECK_ARGUMENT_FOR_NULL(ros_ ## Type, RCL_RET_INVALID_ARGUMENT); \
-  rmw_message_info_t message_info; /* ignored */ \
-  rcl_ret_t ret = rcl_take( \
-    &action_client->impl->Type ## _subscription, ros_ ## Type, &message_info, NULL); \
-  if (RCL_RET_OK != ret) { \
-    if (RCL_RET_SUBSCRIPTION_TAKE_FAILED == ret) { \
-      return RCL_RET_ACTION_CLIENT_TAKE_FAILED; \
-    } \
-    if (RCL_RET_BAD_ALLOC == ret) { \
-      return RCL_RET_BAD_ALLOC; \
-    } \
-    return RCL_RET_ERROR; \
-  } \
-  RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Action " #Type " taken"); \
-  return RCL_RET_OK;
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Taking action " #Type); \
+        if (!rcl_action_client_is_valid(action_client)) { \
+          return RCL_RET_ACTION_CLIENT_INVALID; /* error already set */ \
+        } \
+        RCL_CHECK_ARGUMENT_FOR_NULL(ros_ ## Type, RCL_RET_INVALID_ARGUMENT); \
+        rmw_message_info_t message_info; /* ignored */ \
+        rcl_ret_t ret = rcl_take( \
+          &action_client->impl->Type ## _subscription, ros_ ## Type, &message_info, NULL); \
+        if (RCL_RET_OK != ret) { \
+          if (RCL_RET_SUBSCRIPTION_TAKE_FAILED == ret) { \
+            return RCL_RET_ACTION_CLIENT_TAKE_FAILED; \
+          } \
+          if (RCL_RET_BAD_ALLOC == ret) { \
+            return RCL_RET_BAD_ALLOC; \
+          } \
+          return RCL_RET_ERROR; \
+        } \
+        RCUTILS_LOG_DEBUG_NAMED(ROS_PACKAGE_NAME, "Action " #Type " taken"); \
+        return RCL_RET_OK;
 
 rcl_ret_t
 rcl_action_take_feedback(
@@ -754,16 +762,16 @@ rcl_action_client_set_status_subscription_callback(
 }
 
 #define CLIENT_CONFIGURE_SERVICE_INTROSPECTION(TYPE, STATE) \
-  if (rcl_client_configure_service_introspection( \
-      &action_client->impl->TYPE ## _client, \
-      node, \
-      clock, \
-      type_support->TYPE ## _service_type_support, \
-      publisher_options, \
-      STATE) != RCL_RET_OK) \
-  { \
-    return RCL_RET_ERROR; \
-  }
+        if (rcl_client_configure_service_introspection( \
+            &action_client->impl->TYPE ## _client, \
+            node, \
+            clock, \
+            type_support->TYPE ## _service_type_support, \
+            publisher_options, \
+            STATE) != RCL_RET_OK) \
+        { \
+          return RCL_RET_ERROR; \
+        }
 
 
 rcl_ret_t
@@ -862,16 +870,16 @@ _generate_goal_id_filter_expression(
 
   // Helper macro to append formatted string and check for errors
   #define APPEND_TO_EXPRESSION(...) \
-    do { \
-      int written = snprintf( \
-        expression_goal_id_arrays + pos, expression_capacity - pos, __VA_ARGS__); \
-      if (written < 0 || \
-        written >= expression_capacity - pos || pos + written >= expression_capacity) { \
-        allocator->deallocate(expression_goal_id_arrays, allocator->state); \
-        return RCL_RET_ERROR; \
-      } \
-      pos += written; \
-    } while (0)
+          do { \
+            int written = snprintf( \
+              expression_goal_id_arrays + pos, expression_capacity - pos, __VA_ARGS__); \
+            if (written < 0 || \
+              written >= expression_capacity - pos || pos + written >= expression_capacity) { \
+              allocator->deallocate(expression_goal_id_arrays, allocator->state); \
+              return RCL_RET_ERROR; \
+            } \
+            pos += written; \
+          } while (0)
 
   // Traverse each goal ID array
   for (size_t i = 0; i < num_arrays; i++) {
@@ -996,7 +1004,7 @@ rcl_action_client_configure_feedback_subscription_filter_add_goal_id(
   if (is_cft_enabled) {
     // Existing content filter and append new goal ID to it.
     ret = rcl_subscription_get_content_filter(
-        &action_client->impl->feedback_subscription, &content_filter_options);
+      &action_client->impl->feedback_subscription, &content_filter_options);
     if (RCL_RET_OK != ret) {
       RCL_SET_ERROR_MSG("Failed to get cft expression parameters");
       goto err;
@@ -1151,7 +1159,7 @@ rcl_action_client_configure_feedback_subscription_filter_remove_goal_id(
   rcl_subscription_content_filter_options_t content_filter_options =
     rcl_get_zero_initialized_subscription_content_filter_options();
   ret = rcl_subscription_get_content_filter(
-      &action_client->impl->feedback_subscription, &content_filter_options);
+    &action_client->impl->feedback_subscription, &content_filter_options);
   if (RCL_RET_OK != ret) {
     RCL_SET_ERROR_MSG("Failed to get cft expression parameters");
     return ret;
@@ -1213,8 +1221,8 @@ rcl_action_client_configure_feedback_subscription_filter_remove_goal_id(
       // new_expression_params_size is guaranteed to be less than 100.
       new_expression_params =
         (char **)action_client->impl->options.allocator.allocate(
-          sizeof(char *) * new_expression_params_size,
-          action_client->impl->options.allocator.state);
+        sizeof(char *) * new_expression_params_size,
+        action_client->impl->options.allocator.state);
       if (new_expression_params == NULL) {
         RCL_SET_ERROR_MSG("Failed to allocate memory for expression parameters");
         ret = RCL_RET_BAD_ALLOC;
diff --git a/rcl_action/src/rcl_action/action_client_impl.h b/rcl_action/src/rcl_action/action_client_impl.h
index 4eeb7e91b..e284fcaeb 100644
--- a/rcl_action/src/rcl_action/action_client_impl.h
+++ b/rcl_action/src/rcl_action/action_client_impl.h
@@ -33,7 +33,9 @@ typedef struct rcl_action_client_impl_s
   size_t wait_set_result_client_index;
   size_t wait_set_feedback_subscription_index;
   size_t wait_set_status_subscription_index;
+#ifndef RCL_MICROROS
   rosidl_type_hash_t type_hash;
+#endif  // RCL_MICROROS
 
   /// Disable the content filter feature for feedback subscription.
   /**
diff --git a/rcl_action/src/rcl_action/action_server.c b/rcl_action/src/rcl_action/action_server.c
index 9123e70c4..6ae4e3376 100644
--- a/rcl_action/src/rcl_action/action_server.c
+++ b/rcl_action/src/rcl_action/action_server.c
@@ -27,7 +27,9 @@ extern "C"
 #include "rcl_action/wait.h"
 
 #include "rcl/error_handling.h"
+#ifndef RCL_MICROROS
 #include "rcl/node_type_cache.h"
+#endif  // RCL_MICROROS
 #include "rcl/rcl.h"
 #include "rcl/time.h"
 
@@ -219,7 +221,9 @@ rcl_action_server_init2(
   action_server->impl->goal_handles = NULL;
   action_server->impl->num_goal_handles = 0u;
   action_server->impl->clock = NULL;
+#ifndef RCL_MICROROS
   action_server->impl->type_hash = rosidl_get_zero_initialized_type_hash();
+#endif  // RCL_MICROROS
 
   rcl_ret_t ret = RCL_RET_OK;
 
@@ -279,6 +283,7 @@ rcl_action_server_init2(
     &_enqueue_check_expired_goals);
   (void) dont_care;
 
+#ifndef RCL_MICROROS
   // Store type hash
   ret = rcl_node_type_cache_register_type(
       node, type_support->get_type_hash_func(type_support),
@@ -291,6 +296,7 @@ rcl_action_server_init2(
     goto fail;
   }
   action_server->impl->type_hash = *type_support->get_type_hash_func(type_support);
+#endif  // RCL_MICROROS
 
   return ret;
 fail:
@@ -356,12 +362,14 @@ rcl_action_server_fini(rcl_action_server_t * action_server, rcl_node_t * node)
     }
     allocator.deallocate(action_server->impl->goal_handles, allocator.state);
     action_server->impl->goal_handles = NULL;
+#ifndef RCL_MICROROS
     if (
       ROSIDL_TYPE_HASH_VERSION_UNSET != action_server->impl->type_hash.version &&
       RCL_RET_OK != rcl_node_type_cache_unregister_type(node, &action_server->impl->type_hash))
     {
       ret = RCL_RET_ERROR;
     }
+#endif  // RCL_MICROROS
     // Deallocate struct
     allocator.deallocate(action_server->impl, allocator.state);
     action_server->impl = NULL;
diff --git a/rcl_action/src/rcl_action/action_server_impl.h b/rcl_action/src/rcl_action/action_server_impl.h
index 8e6a1eb69..3be29971e 100644
--- a/rcl_action/src/rcl_action/action_server_impl.h
+++ b/rcl_action/src/rcl_action/action_server_impl.h
@@ -41,7 +41,9 @@ typedef struct rcl_action_server_impl_s
   size_t wait_set_cancel_service_index;
   size_t wait_set_result_service_index;
   size_t wait_set_expire_timer_index;
+#ifndef RCL_MICROROS
   rosidl_type_hash_t type_hash;
+#endif  // RCL_MICROROS
 } rcl_action_server_impl_t;