diff --git a/gen/extract.py b/gen/extract.py
index c01c504..16d103a 100755
--- a/gen/extract.py
+++ b/gen/extract.py
@@ -4,6 +4,8 @@
 import re
 import os
 import pprint
+import json
+
 
 def create_paths_list(dirname, filenames):
     paths = []
@@ -35,43 +37,53 @@ def extract_functions(file_content):
     return res
 
 
+def process(header, out_dir):
+    # Process and create data structure
+    print("processing path: " + header.get("path") + "...")
+    basename = os.path.basename(header.get("path"))
+    # strip suffix, will be added output format dependently
+    basename_minus_suffix = re.sub("\..*$",'',basename)
+
+    # add outpath
+    outpath = out_dir + basename_minus_suffix
+    header["outpath"] = outpath
+
+    # add functions
+    functions = extract_functions(header.get("content"))
+    header["functions"] = functions
+
+    return header
+
+
+def write_json(header):
+    header["outpath"] += ".json"
+    with open(header.get("outpath"), "w+") as f:
+        json.dump(header, f, indent=4)
+
+
+
 def main():
     # Input
     prefix = r"/Users/heck/local-default/"
     filenames = ["pEpEngine.h",
                  "keymanagement.h"]
-
     # Output
     out_dir = "data/"
 
     basename = prefix + r"include/pEp/"
 
-    # Create out dir
     if not os.path.isdir(out_dir):
         os.makedirs(out_dir)
 
-    # Parse input
     paths = create_paths_list(basename, filenames)
     headers = read_files(paths)
 
-    # Process and create data structure
     for header in headers:
-        print("processing path: " + header.get("path") + "...")
-        basename = os.path.basename(header.get("path"))
-
-        # add outpath
-        outpath = out_dir + basename
-        header["outpath"] = outpath
+        # Process
+        header = process(header, out_dir)
+        # Output
+        write_json(header)
 
-        # add functions
-        functions = extract_functions(header.get("content"))
-        header["functions"] = functions
-
-
-    # Output
-    for header in headers:
-        with open(header.get("outpath"), "w+") as f:
-            pprint.pp(header)
 
 if __name__ == "__main__":
     main()