diff --git a/hello-world/main.c b/hello-world/main.c
index 590f841..2e217a6 100644
--- a/hello-world/main.c
+++ b/hello-world/main.c
@@ -23,7 +23,7 @@ int main(int argc, char *argv[]) {
 
   printf("main() Started...\n");
   if (argc != 2) {
-    fprintf(stderr, "Usage: ./main <port>\n");
+    fprintf(stderr, "Usage: %s <port>\n", argv[0]);
     exit(1);
   }
 
diff --git a/libjansson/main.c b/libjansson/main.c
new file mode 100644
index 0000000..8c24c1c
--- /dev/null
+++ b/libjansson/main.c
@@ -0,0 +1,132 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <ulfius.h>
+#include <jansson.h>
+
+#define ROUTE_HELLO "/hello"
+
+/**
+ * callback functions declaration
+ */
+int callback_get_hello (const struct _u_request * request, struct _u_response * response, void * user_data);
+
+int callback_default (const struct _u_request * request, struct _u_response * response, void * user_data);
+
+int main(int argc, char *argv[]) {
+  /*declaration*/
+  struct _u_instance instance;
+  unsigned int port;
+  int ret;
+
+  printf("main() Started...\n");
+  if (argc != 2) {
+    fprintf(stderr, "Usage: %s <port>\n", argv[0]);
+    exit(1);
+  }
+
+  printf("main() argv[1]: %s\n", argv[1]);
+
+  /*store command line argument in int variable*/
+  /*validate user input*/
+  /*omit injection*/
+  /*stream:argv*/
+  ret = sscanf(argv[1], "%d", &port);
+
+  /*valid user input:1 successfully filled item*/
+  if (ret != 1) {
+    fprintf(stderr, "The argument must be an integer\n");
+    exit(1);
+  }
+
+  if (port < 0) {
+    fprintf(stderr, "Error passing a negative port\n");
+    exit(1);
+  }
+  printf("main() port: %d\n", port);
+
+  if (ulfius_init_instance(&instance, port, NULL, NULL) != U_OK) {
+    printf("main() Error ulfius_init_instance, abort");
+    return(1);
+  }
+
+  //TODO Why?
+  u_map_put(instance.default_headers, "Access-Control-Allow-Origin", "*");  
+
+  // Maximum body size sent by the client is 1 Kb
+  instance.max_post_body_size = 1024;
+
+  // Endpoint list declaration
+  ulfius_add_endpoint_by_val(&instance, "GET", ROUTE_HELLO, NULL, 0, &callback_get_hello, NULL);
+
+  // default_endpoint declaration
+  ulfius_set_default_endpoint(&instance, &callback_default, NULL);
+
+  // Start the framework
+  // Open an http connection
+  ret = ulfius_start_framework(&instance);
+
+  if (ret == U_OK) {
+    printf("main() Start framework on port %d\n", instance.port);
+    
+    // Wait for the user to press <enter> on the console to quit the application
+    getchar();
+  } else {
+    printf("main() Error starting framework\n");
+  }
+
+  printf("main() End framework\n");
+  
+  ulfius_stop_framework(&instance);
+  ulfius_clean_instance(&instance);
+
+  printf("main() Done.\n");
+
+  return 0;
+}
+    
+/**
+ * Callback function that put a "Hello World!" string in the response
+ */
+int callback_get_hello (const struct _u_request * request, struct _u_response * response, void * user_data) {
+
+  /*declaration*/
+  json_t *array, *integer1, *integer2;
+  json_int_t * json_nb;
+  int number;
+  size_t size;
+
+  /*pg int*/
+  number = 42;
+  json_nb = (void *)&number;
+  printf("address of number: %p\n", &number); 
+  printf("address of json_nb: %p\n", json_nb); 
+  printf("value of number: %d\n", number); 
+  printf("value of json_nb: %lld\n", *json_nb); 
+
+  /*pg array*/
+  array = json_array();
+  integer1 = json_integer(42);
+  integer2 = json_integer(23);
+  json_array_append(array, integer1);
+  json_array_append(array, integer2);
+  json_decref(integer1);
+  json_decref(integer2);
+  size = json_array_size(array);
+  fprintf(stdout,"main() size: %ld\n", size);
+
+  ulfius_set_json_body_response(response, 200, array);
+  json_decref(array);
+  return U_CALLBACK_CONTINUE;
+}
+
+/**
+ * Default callback function called if no endpoint has a match
+ */
+int callback_default (const struct _u_request * request, struct _u_response * response, void * user_data) {
+  ulfius_set_string_body_response(response, 404, "Page not found, do what you want");
+  return U_CALLBACK_CONTINUE;
+}
diff --git a/libjansson/makefile b/libjansson/makefile
new file mode 100644
index 0000000..6ffc946
--- /dev/null
+++ b/libjansson/makefile
@@ -0,0 +1,24 @@
+# Docu
+#
+#$@ is the name of the file to be made
+#$? is the names of the changed dependents
+#$< the name of the related file that caused the action
+#$* the prefix shared by target and dependent files
+#
+# Others
+RM      = /bin/rm -f
+#
+# Source, Executable, Includes, Library Defines
+EXE    = main
+#
+# Compiler, Linker Defines
+CC      = /usr/bin/gcc
+#
+all: main.o
+	$(CC) main.c -L/usr/lib/x86_64-linux-gnu -lulfius -ljansson -Wall -o $(EXE)
+#
+main.o:
+	$(CC) -c main.c
+# Clean Up Objects, Exectuables, Dumps out of source directory
+clean:
+	$(RM) *.o $(EXE) *~
diff --git a/libjansson/readme.md b/libjansson/readme.md
new file mode 100644
index 0000000..7d6447b
--- /dev/null
+++ b/libjansson/readme.md
@@ -0,0 +1,11 @@
+* build
+
+```
+make
+```
+
+* run
+
+```
+./main <port>
+```