diff --git a/config.h b/config.h
index 7b9ce3b4b..bd7433023 100644
--- a/config.h
+++ b/config.h
@@ -99,4 +99,6 @@ typedef SSIZE_T ssize_t;
 #  define BROKER_EXPORT
 #endif
 
+#define TOPIC_HIERARCHY_LIMIT 200
+
 #endif
diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index ad099c3ad..f116428fd 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -48,7 +48,7 @@ set(C_SRC
 	srv_mosq.c
 	thread_mosq.c
 	tls_mosq.c
-	util_mosq.c util_topic.c util_mosq.h
+	util_mosq.c util_mosq.h
 	will_mosq.c will_mosq.h)
 
 if (WITH_THREADING AND WIN32)
diff --git a/lib/Makefile b/lib/Makefile
index 5559b9962..66c05ca26 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -81,7 +81,6 @@ OBJS= \
 	thread_mosq.o \
 	tls_mosq.o \
 	util_mosq.o \
-	util_topic.o \
 	will_mosq.o
 
 OBJS_EXTERNAL= \
diff --git a/libcommon/CMakeLists.txt b/libcommon/CMakeLists.txt
index 4c0ec2dac..75a9c49d6 100644
--- a/libcommon/CMakeLists.txt
+++ b/libcommon/CMakeLists.txt
@@ -1,6 +1,7 @@
 set(C_SRC
 	strings_common.c
 	time_common.c
+	topic_common.c
 	utf8_common.c
 )
 
diff --git a/libcommon/Makefile b/libcommon/Makefile
index 3c6ca1553..d164b973a 100644
--- a/libcommon/Makefile
+++ b/libcommon/Makefile
@@ -14,6 +14,7 @@ LOCAL_LIBADD+=
 OBJS= \
 	strings_common.o \
 	time_common.o \
+	topic_common.o \
 	utf8_common.o
 
 all : libmosquitto_common.a
diff --git a/lib/util_topic.c b/libcommon/topic_common.c
similarity index 96%
rename from lib/util_topic.c
rename to libcommon/topic_common.c
index 2e20779d9..3fda91825 100644
--- a/lib/util_topic.c
+++ b/libcommon/topic_common.c
@@ -29,17 +29,7 @@ Contributors:
 #  include <sys/stat.h>
 #endif
 
-
-#ifdef WITH_BROKER
-#include "mosquitto_broker_internal.h"
-#endif
-
 #include "mosquitto.h"
-#include "memory_mosq.h"
-#include "net_mosq.h"
-#include "send_mosq.h"
-#include "tls_mosq.h"
-#include "util_mosq.h"
 
 /* Check that a topic used for publishing is valid.
  * Search for + or # in a topic. Return MOSQ_ERR_INVAL if found.
@@ -49,9 +39,7 @@ Contributors:
 BROKER_EXPORT int mosquitto_pub_topic_check(const char *str)
 {
 	int len = 0;
-#ifdef WITH_BROKER
 	int hier_count = 0;
-#endif
 
 	if(str == NULL){
 		return MOSQ_ERR_INVAL;
@@ -60,19 +48,14 @@ BROKER_EXPORT int mosquitto_pub_topic_check(const char *str)
 	while(str && str[0]){
 		if(str[0] == '+' || str[0] == '#'){
 			return MOSQ_ERR_INVAL;
-		}
-#ifdef WITH_BROKER
-		else if(str[0] == '/'){
+		}else if(str[0] == '/'){
 			hier_count++;
 		}
-#endif
 		len++;
 		str = &str[1];
 	}
 	if(len > 65535) return MOSQ_ERR_INVAL;
-#ifdef WITH_BROKER
 	if(hier_count > TOPIC_HIERARCHY_LIMIT) return MOSQ_ERR_INVAL;
-#endif
 
 	return MOSQ_ERR_SUCCESS;
 }
@@ -80,9 +63,7 @@ BROKER_EXPORT int mosquitto_pub_topic_check(const char *str)
 BROKER_EXPORT int mosquitto_pub_topic_check2(const char *str, size_t len)
 {
 	size_t i;
-#ifdef WITH_BROKER
 	int hier_count = 0;
-#endif
 
 	if(str == NULL || len > 65535){
 		return MOSQ_ERR_INVAL;
@@ -91,16 +72,11 @@ BROKER_EXPORT int mosquitto_pub_topic_check2(const char *str, size_t len)
 	for(i=0; i<len; i++){
 		if(str[i] == '+' || str[i] == '#'){
 			return MOSQ_ERR_INVAL;
-		}
-#ifdef WITH_BROKER
-		else if(str[i] == '/'){
+		}else if(str[i] == '/'){
 			hier_count++;
 		}
-#endif
 	}
-#ifdef WITH_BROKER
 	if(hier_count > TOPIC_HIERARCHY_LIMIT) return MOSQ_ERR_INVAL;
-#endif
 
 	return MOSQ_ERR_SUCCESS;
 }
@@ -116,9 +92,7 @@ BROKER_EXPORT int mosquitto_sub_topic_check(const char *str)
 {
 	char c = '\0';
 	int len = 0;
-#ifdef WITH_BROKER
 	int hier_count = 0;
-#endif
 
 	if(str == NULL){
 		return MOSQ_ERR_INVAL;
@@ -133,20 +107,15 @@ BROKER_EXPORT int mosquitto_sub_topic_check(const char *str)
 			if((c != '\0' && c != '/')  || str[1] != '\0'){
 				return MOSQ_ERR_INVAL;
 			}
-		}
-#ifdef WITH_BROKER
-		else if(str[0] == '/'){
+		}else if(str[0] == '/'){
 			hier_count++;
 		}
-#endif
 		len++;
 		c = str[0];
 		str = &str[1];
 	}
 	if(len > 65535) return MOSQ_ERR_INVAL;
-#ifdef WITH_BROKER
 	if(hier_count > TOPIC_HIERARCHY_LIMIT) return MOSQ_ERR_INVAL;
-#endif
 
 	return MOSQ_ERR_SUCCESS;
 }
@@ -155,9 +124,7 @@ BROKER_EXPORT int mosquitto_sub_topic_check2(const char *str, size_t len)
 {
 	char c = '\0';
 	size_t i;
-#ifdef WITH_BROKER
 	int hier_count = 0;
-#endif
 
 	if(str == NULL || len > 65535){
 		return MOSQ_ERR_INVAL;
@@ -172,17 +139,12 @@ BROKER_EXPORT int mosquitto_sub_topic_check2(const char *str, size_t len)
 			if((c != '\0' && c != '/')  || i<len-1){
 				return MOSQ_ERR_INVAL;
 			}
-		}
-#ifdef WITH_BROKER
-		else if(str[i] == '/'){
+		}else if(str[i] == '/'){
 			hier_count++;
 		}
-#endif
 		c = str[i];
 	}
-#ifdef WITH_BROKER
 	if(hier_count > TOPIC_HIERARCHY_LIMIT) return MOSQ_ERR_INVAL;
-#endif
 
 	return MOSQ_ERR_SUCCESS;
 }
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1e1bb01ca..56eca3889 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -74,7 +74,7 @@ set (MOSQ_SRCS
 	sys_tree.c sys_tree.h
 	../lib/tls_mosq.c
 	topic_tok.c
-	../lib/util_mosq.c ../lib/util_topic.c ../lib/util_mosq.h
+	../lib/util_mosq.c ../lib/util_mosq.h
 	websockets.c
 	will_delay.c
 	../lib/will_mosq.c ../lib/will_mosq.h
diff --git a/src/Makefile b/src/Makefile
index c98ac4a31..da726c493 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -138,7 +138,6 @@ OBJS_EXTERNAL= \
 		send_unsubscribe.o \
 		tls_mosq.o \
 		util_mosq.o \
-		util_topic.o \
 		will_mosq.o
 
 ifeq ($(WITH_WEBSOCKETS),yes)
@@ -235,9 +234,6 @@ tls_mosq.o : ${R}/lib/tls_mosq.c
 util_mosq.o : ${R}/lib/util_mosq.c ${R}/lib/util_mosq.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(LOCAL_CFLAGS) -c $< -o $@
 
-util_topic.o : ${R}/lib/util_topic.c ${R}/lib/util_mosq.h
-	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(LOCAL_CFLAGS) -c $< -o $@
-
 will_mosq.o : ${R}/lib/will_mosq.c ${R}/lib/will_mosq.h
 	${CROSS_COMPILE}${CC} $(LOCAL_CPPFLAGS) $(LOCAL_CFLAGS) -c $< -o $@
 
diff --git a/src/mosquitto_broker_internal.h b/src/mosquitto_broker_internal.h
index 64d17dfab..22c8cfe8b 100644
--- a/src/mosquitto_broker_internal.h
+++ b/src/mosquitto_broker_internal.h
@@ -61,7 +61,6 @@ Contributors:
 #define MQTT3_LOG_ALL 0xFF
 
 #define CMD_PORT_LIMIT 10
-#define TOPIC_HIERARCHY_LIMIT 200
 
 typedef uint64_t dbid_t;
 
diff --git a/test/unit/broker/CMakeLists.txt b/test/unit/broker/CMakeLists.txt
index 23e77fa1e..e2c9dd9a2 100644
--- a/test/unit/broker/CMakeLists.txt
+++ b/test/unit/broker/CMakeLists.txt
@@ -3,7 +3,6 @@ add_library(bridge-topic-obj
 	OBJECT
 	../../../src/bridge_topic.c
 	../../../lib/memory_mosq.c
-	../../../lib/util_topic.c
 )
 target_compile_definitions(bridge-topic-obj PRIVATE WITH_BRIDGE WITH_BROKER)
 target_link_libraries(bridge-topic-obj PUBLIC common-unit-test-header)
@@ -13,7 +12,7 @@ add_executable(bridge-topic-test
     stubs.c
 )
 target_compile_definitions(bridge-topic-test PRIVATE WITH_BRIDGE WITH_BROKER)
-target_link_libraries(bridge-topic-test PRIVATE bridge-topic-obj common-unit-test-header)
+target_link_libraries(bridge-topic-test PRIVATE bridge-topic-obj common-unit-test-header libmosquitto_common)
 add_test(NAME unit-bridge-topic-test COMMAND bridge-topic-test)
 
 # keepalive-test
diff --git a/test/unit/broker/Makefile b/test/unit/broker/Makefile
index 92af98222..39c248332 100644
--- a/test/unit/broker/Makefile
+++ b/test/unit/broker/Makefile
@@ -21,8 +21,7 @@ BRIDGE_TOPIC_OBJS = \
 		${R}/src/bridge_topic.o \
 		${R}/src/memory_mosq.o \
 		${R}/src/packet_datatypes.o \
-		${R}/src/property_mosq.o \
-		${R}/src/util_topic.o
+		${R}/src/property_mosq.o
 
 KEEPALIVE_TEST_OBJS = \
 		keepalive_stubs.o \
@@ -170,9 +169,6 @@ ${R}/src/topic_tok.o : ${R}/src/topic_tok.c
 ${R}/src/util_mosq.o : ${R}/lib/util_mosq.c
 	$(MAKE) -C ${R}/src/ util_mosq.o
 
-${R}/src/util_topic.o : ${R}/lib/util_topic.c
-	$(MAKE) -C ${R}/src/ util_topic.o
-
 build : bridge_topic_test keepalive_test persist_read_test persist_write_test subs_test
 
 test : build
diff --git a/test/unit/lib/CMakeLists.txt b/test/unit/lib/CMakeLists.txt
index 46880b4e7..a744a8762 100644
--- a/test/unit/lib/CMakeLists.txt
+++ b/test/unit/lib/CMakeLists.txt
@@ -8,7 +8,6 @@ add_executable(lib-test
 	property_write.c
 	property_value.c
 	stubs.c
-	util_topic_test.c
 	# main test files
 	test.c
 	../../../lib/memory_mosq.c
@@ -17,7 +16,6 @@ add_executable(lib-test
 	../../../lib/packet_mosq.c
 	../../../lib/property_mosq.c
 	../../../lib/util_mosq.c
-	../../../lib/util_topic.c
 )
 
 target_link_libraries(lib-test PRIVATE common-unit-test-header OpenSSL::SSL libmosquitto_common)
diff --git a/test/unit/lib/Makefile b/test/unit/lib/Makefile
index 745f93f37..2a6e9f0bf 100644
--- a/test/unit/lib/Makefile
+++ b/test/unit/lib/Makefile
@@ -23,7 +23,6 @@ TEST_OBJS = \
 	property_write.o \
 	property_value.o \
 	stubs.o \
-	util_topic_test.o
 
 LIB_OBJS = \
 	${R}/lib/memory_mosq.o \
@@ -31,8 +30,7 @@ LIB_OBJS = \
 	${R}/lib/packet_datatypes.o \
 	${R}/lib/packet_mosq.o \
 	${R}/lib/property_mosq.o \
-	${R}/lib/util_mosq.o \
-	${R}/lib/util_topic.o
+	${R}/lib/util_mosq.o
 
 
 all : test-compile
@@ -66,9 +64,6 @@ ${R}/lib/property_mosq.o : ${R}/lib/property_mosq.c
 ${R}/lib/util_mosq.o : ${R}/lib/util_mosq.c
 	$(MAKE) -C ${R}/lib/ util_mosq.o
 
-${R}/lib/util_topic.o : ${R}/lib/util_topic.c
-	$(MAKE) -C ${R}/lib/ util_topic.o
-
 ${R}/lib/utf8_mosq.o : ${R}/common/utf8_mosq.c
 	$(MAKE) -C ${R}/lib/ utf8_mosq.o
 
diff --git a/test/unit/lib/test.c b/test/unit/lib/test.c
index 547ca6ed3..cd8c7d501 100644
--- a/test/unit/lib/test.c
+++ b/test/unit/lib/test.c
@@ -11,7 +11,6 @@ int init_property_read_tests(void);
 int init_property_user_read_tests(void);
 int init_property_write_tests(void);
 int init_property_value_tests(void);
-int init_util_topic_tests(void);
 int init_misc_trim_tests(void);
 
 int main(int argc, char *argv[])
@@ -34,7 +33,6 @@ int main(int argc, char *argv[])
 			|| init_property_user_read_tests()
 			|| init_property_write_tests()
 			|| init_property_value_tests()
-			|| init_util_topic_tests()
 			|| init_misc_trim_tests()
 			){
 
diff --git a/test/unit/libcommon/CMakeLists.txt b/test/unit/libcommon/CMakeLists.txt
index e4230dad2..b5337ea24 100644
--- a/test/unit/libcommon/CMakeLists.txt
+++ b/test/unit/libcommon/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_executable(libcommon-test
 	strings_test.c
 	test.c
+	topic_test.c
 	utf8.c
 )
 
diff --git a/test/unit/libcommon/Makefile b/test/unit/libcommon/Makefile
index 9ff07eaa4..4fdda0f93 100644
--- a/test/unit/libcommon/Makefile
+++ b/test/unit/libcommon/Makefile
@@ -15,6 +15,7 @@ endif
 TEST_OBJS = \
 	strings_test.o \
 	test.o \
+	topic_test.o \
 	utf8.o \
 
 LIB_OBJS =
diff --git a/test/unit/libcommon/test.c b/test/unit/libcommon/test.c
index 85e47936c..247441a85 100644
--- a/test/unit/libcommon/test.c
+++ b/test/unit/libcommon/test.c
@@ -5,6 +5,7 @@
 #include <CUnit/Basic.h>
 
 int init_strings_tests(void);
+int init_topic_tests(void);
 int init_utf8_tests(void);
 
 int main(int argc, char *argv[])
@@ -21,6 +22,7 @@ int main(int argc, char *argv[])
 
     if(0
 			|| init_strings_tests()
+			|| init_topic_tests()
 			|| init_utf8_tests()
 			){
 
diff --git a/test/unit/lib/util_topic_test.c b/test/unit/libcommon/topic_test.c
similarity index 99%
rename from test/unit/lib/util_topic_test.c
rename to test/unit/libcommon/topic_test.c
index 55c06c561..95ae6eadd 100644
--- a/test/unit/lib/util_topic_test.c
+++ b/test/unit/libcommon/topic_test.c
@@ -1458,7 +1458,7 @@ static void TEST_sub_match_acl(void)
  * TEST SUITE SETUP
  * ======================================================================== */
 
-int init_util_topic_tests(void)
+int init_topic_tests(void)
 {
 	CU_pSuite test_suite = NULL;