diff --git a/tools/netdiff.py b/tools/netdiff.py
new file mode 100755
index 0000000000..8cbbeec8ff
--- /dev/null
+++ b/tools/netdiff.py
@@ -0,0 +1,161 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2019 Jon Evans <jon@craftyjon.com>
+
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+# This utility compares two netlists generated by Eeschema and reports on
+# connectivity differences between them.  This only is looking at connectivity!
+# Things like the components section, the visual format of the file, and the
+# sorting of entries is not compared.
+
+import argparse
+import json
+import os
+import sexpdata
+import sys
+
+
+def extract_nets(sexpr):
+    # Starts with ( export (version N) (...) )
+    for idx, key in enumerate(sexpr):
+        # print("{}: {}".format(idx, key))
+        if isinstance(key, list):
+            if isinstance(key[0], sexpdata.Symbol) and key[0].value() == "nets":
+                return key[1:]
+    return None
+
+
+def unpack(sexpr):
+    ret = {}
+    for net in sexpr:
+        code = net[1][1]
+        name = net[2][1]
+        if isinstance(name, sexpdata.Symbol):
+            name = name.value()
+        name = str(name)
+
+        members = []
+        if len(net) < 4:
+            continue
+
+        for node in net[3:]:
+            ref = node[1][1]
+            pin = node[2][1]
+
+            if isinstance(ref, sexpdata.Symbol):
+                ref = ref.value()
+
+            if isinstance(pin, sexpdata.Symbol):
+                pin = pin.value()
+
+            ref = str(ref)
+            pin = str(pin)
+
+            members.append((ref, pin))
+
+        members.sort()
+        ret[name] = members
+
+    return ret
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description='Compare KiCad netlists')
+    parser.add_argument('first_netlist')
+    parser.add_argument('second_netlist')
+
+    args = parser.parse_args()
+
+    fn_a = args.first_netlist
+    fn_b = args.second_netlist
+
+    with open(fn_a, 'r') as f:
+        a = sexpdata.load(f)
+
+    with open(fn_b, 'r') as f:
+        b = sexpdata.load(f)
+
+    # Extract the nets portion
+    a = extract_nets(a)
+    b = extract_nets(b)
+
+    if a is None:
+        print("Could not read nets from {}".format(fn_a))
+        sys.exit(1)
+
+    if b is None:
+        print("Could not read nets from {}".format(fn_b))
+        sys.exit(1)
+
+    nets_a = unpack(a)
+    nets_b = unpack(b)
+
+    sa = set(nets_a.keys())
+    sb = set(nets_b.keys())
+
+    only_a = sa - sb
+    only_b = sb - sa
+    both = sa & sb
+
+    if len(only_a) == len(only_b) == 0:
+        print("{} and {} are identical".format(fn_a, fn_b))
+        sys.exit(0)
+
+    print("A: {}\nB: {}".format(fn_a, fn_b))
+
+    changed_header = False
+
+    for net_name in sorted(both):
+        if nets_a[net_name] != nets_b[net_name]:
+            if not changed_header:
+                print("\nChanged nets:\n")
+                changed_header = True
+
+            print("{}: {} => {}".format(net_name, nets_a[net_name],
+                                        nets_b[net_name]))
+
+    discards_a = set()
+    discards_b = set()
+
+    renamed_header = False
+
+    for net_name in sorted(only_a):
+        for candidate in only_b:
+            if nets_a[net_name] == nets_b[candidate]:
+                if not renamed_header:
+                    print("\nRenamed nets (no connection changes):\n")
+                    renamed_header = True
+
+                print("{} => {}".format(net_name, candidate))
+                discards_a.add(net_name)
+                discards_b.add(candidate)
+
+    only_a.difference_update(discards_a)
+    only_b.difference_update(discards_b)
+
+    if len(only_a) > 0:
+        print("\nOnly in {}:\n".format(fn_a))
+        print('\n'.join(["{}: {}".format(el, nets_a[el])
+                        for el in sorted(only_a)]))
+
+    if len(only_b) > 0:
+        print("\nOnly in {}:\n".format(fn_b))
+        print('\n'.join(["{}: {}".format(el, nets_b[el])
+                        for el in sorted(only_b)]))