diff --git a/libmxclient/mxclientlib.go b/libmxclient/mxclientlib.go
index 436fa81..004e1f3 100644
--- a/libmxclient/mxclientlib.go
+++ b/libmxclient/mxclientlib.go
@@ -5,10 +5,19 @@ package main
 import (
 	"fmt"
 	"mxclientlib/mxclient"
+	"unsafe"
 )
 
+/*
+#include <stdlib.h>
+*/
 import "C"
 
+//export FreeCString
+func FreeCString(s *C.char) {
+	C.free(unsafe.Pointer(s))
+}
+
 /*
 cli tools
 */
diff --git a/pygomx/build_ffi.py b/pygomx/build_ffi.py
index bba549d..64feb06 100644
--- a/pygomx/build_ffi.py
+++ b/pygomx/build_ffi.py
@@ -13,6 +13,7 @@ ffibuilder.set_source(
 
 ffibuilder.cdef(
     csource="""
+    extern void  FreeCString(char * s);
     extern char* cli_discoverhs(char* mxid);
     extern char* cli_mkmxtoken(char* mxid, char* pw);
     extern char* cli_whoami(char* hs, char* accessToken);
diff --git a/smal/src/pymxutils/mxutils/accountinfo.py b/smal/src/pymxutils/mxutils/accountinfo.py
index a492b1e..fa08f3d 100644
--- a/smal/src/pymxutils/mxutils/accountinfo.py
+++ b/smal/src/pymxutils/mxutils/accountinfo.py
@@ -12,4 +12,5 @@ def accountinfo():
 
     r = lib.cli_accountinfo(url, tk)
     result = ffi.string(r)
+    lib.FreeCString(r)
     print(result)
diff --git a/smal/src/pymxutils/mxutils/clearaccount.py b/smal/src/pymxutils/mxutils/clearaccount.py
index 8d494f1..d8cf003 100644
--- a/smal/src/pymxutils/mxutils/clearaccount.py
+++ b/smal/src/pymxutils/mxutils/clearaccount.py
@@ -12,4 +12,5 @@ def clearaccount():
 
     r = lib.cli_clearaccount(url, tk)
     result = ffi.string(r)
+    lib.FreeCString(r)
     print(result)
diff --git a/smal/src/pymxutils/mxutils/discoverhs.py b/smal/src/pymxutils/mxutils/discoverhs.py
index 547232e..9da3dd7 100644
--- a/smal/src/pymxutils/mxutils/discoverhs.py
+++ b/smal/src/pymxutils/mxutils/discoverhs.py
@@ -13,4 +13,5 @@ def discoverhs():
 
     r = lib.cli_discoverhs(mxid)
     result = ffi.string(r)
+    lib.FreeCString(r)
     print(result)
diff --git a/smal/src/pymxutils/mxutils/mktoken.py b/smal/src/pymxutils/mxutils/mktoken.py
index 38fdc58..27b0d7d 100644
--- a/smal/src/pymxutils/mxutils/mktoken.py
+++ b/smal/src/pymxutils/mxutils/mktoken.py
@@ -12,4 +12,5 @@ def mktoken():
 
     r = lib.cli_mkmxtoken(mxid, pw)
     result = ffi.string(r)
+    lib.FreeCString(r)
     print(result)
diff --git a/smal/src/pymxutils/mxutils/serverinfo.py b/smal/src/pymxutils/mxutils/serverinfo.py
index f72807f..7a64535 100644
--- a/smal/src/pymxutils/mxutils/serverinfo.py
+++ b/smal/src/pymxutils/mxutils/serverinfo.py
@@ -11,4 +11,5 @@ def serverinfo():
 
     r = lib.cli_serverinfo(mxdomain)
     result = ffi.string(r)
+    lib.FreeCString(r)
     print(result)
diff --git a/smal/src/pymxutils/mxutils/whoami.py b/smal/src/pymxutils/mxutils/whoami.py
index e41241d..7863cb5 100644
--- a/smal/src/pymxutils/mxutils/whoami.py
+++ b/smal/src/pymxutils/mxutils/whoami.py
@@ -12,4 +12,5 @@ def whoami():
 
     r = lib.cli_whoami(url, tk)
     result = ffi.string(r)
+    lib.FreeCString(r)
     print(result)