diff --git a/bin/gftools-ufo-fix-mm.py b/bin/gftools-ufo-fix-mm.py
new file mode 100755
index 000000000..112128ce9
--- /dev/null
+++ b/bin/gftools-ufo-fix-mm.py
@@ -0,0 +1,186 @@
+#!/usr/bin/env python3
+"""
+Primitive ufo prepolator!
+
+Fix ufo and designspace glyph incompatibilities. It can
+currently fix:
+- starting points
+- contour order
+- component order
+
+Users will need to manually fix paths which have different node counts.
+
+Warning mega destructive! TODO work on duplicates instead of overwriting.
+Always use version control!
+
+This may take a while for families which contain many masters.
+
+
+Usage:
+
+# fix ufos
+gftools ufo-fix-mm font1.ufo font2.ufo
+
+# fix designspaces
+gftools ufo-fix-mm family.designspace
+"""
+from fontTools.designspaceLib import DesignSpaceDocument
+from fontTools.varLib.interpolatable import test
+from ufoLib2 import Font
+import os
+from itertools import permutations
+import argparse
+
+
+def _fix_starting_points(glyphsets, base_font, font, glyph, names, idx):
+    base_glyph = base_font[glyph]
+    font_glyph = font[glyph]
+    font.save()
+    test_order = test(
+        [glyphsets[0], font.reader.getGlyphSet()], glyphs=[glyph], names=names
+    )
+    test_compatibility = nodes_compatible(base_font, font, glyph)
+    if len(test_order) == 0 and test_compatibility:
+        print(f"{glyph}: Fixed starting points")
+        return True
+    if idx == len(font_glyph):
+        return False
+
+    for _ in range(len(font_glyph[idx])):
+        # incrememt starting point by next node
+        font_glyph[idx].append(font_glyph[idx].pop(0))
+        # check that both paths have the same node types
+        font_nodes = [n.type for n in font_glyph[idx]]
+        base_nodes = [n.type for n in base_glyph[idx]]
+        if font_nodes != base_nodes:
+            continue
+
+        if _fix_starting_points(glyphsets, base_font, font, glyph, names, idx + 1):
+            return True
+    return False
+
+
+def fix_starting_points(glyphsets, base_font, font, glyph, names):
+    fixed = _fix_starting_points(glyphsets, base_font, font, glyph, names, 0)
+    if not fixed:
+        print(f"{glyph}: Failed fixing starting points")
+        return False
+    return True
+
+
+def nodes_compatible(base_font, font, glyph):
+    base_font_nodes = []
+    font_nodes = []
+
+    for cont in base_font[glyph]:
+        for pt in cont:
+            base_font_nodes.append(pt.type)
+
+    for cont in font[glyph]:
+        for pt in cont:
+            font_nodes.append(pt.type)
+    return base_font_nodes == font_nodes
+
+
+def components_compatible(base_font, font, glyph):
+    base_font_components = [c.baseGlyph for c in base_font[glyph].components]
+    font_components = [c.baseGlyph for c in font[glyph].components]
+    return base_font_components == font_components
+
+
+def fix_contour_order(glyphsets, font, glyph, names):
+    contours = font[glyph].contours
+    perms = permutations(contours)
+    for perm in perms:
+        font[glyph].clearContours()
+        for contour in perm:
+            font[glyph].appendContour(contour)
+        font.save()
+        res = test(
+            [glyphsets[0], font.reader.getGlyphSet()], glyphs=[glyph], names=names
+        )
+        if len(res) == 0:
+            print(f"{glyph}: Fixed contour order")
+            return
+    print(f"{glyph}: Failed fixing contour order")
+
+
+def fix_component_order(base_font, font, glyph):
+    components = font[glyph].components
+    perms = permutations(components)
+    for perm in perms:
+        font[glyph].clearComponents()
+        for comp in perm:
+            font[glyph].components.append(comp)
+        font.save()
+        res = components_compatible(base_font, font, glyph)
+        if res:
+            print(f"{glyph}: Fixed component order")
+            return
+    print(f"{glyph}: Failed fixing component order")
+
+
+def main():
+    parser = argparse.ArgumentParser(__doc__)
+    parser.add_argument(
+        "fonts", nargs="+", help="Source files. Either ufos of designspace."
+    )
+    args = parser.parse_args()
+
+    sources = []
+    for src in args.fonts:
+        if src.endswith(".designspace"):
+            ds = DesignSpaceDocument()
+            ds.read(src)
+            for s in ds.sources:
+                if s in sources:
+                    continue
+                sources.append(s.path)
+        else:
+            sources.append(src)
+
+    if len(sources) == 1:
+        raise ValueError("Single source family! cannot check.")
+
+    names = [os.path.basename(f) for f in sources[1:]]
+    fonts = [Font.open(f) for f in sources]
+    glyphsets = [f.reader.getGlyphSet() for f in fonts]
+    base_font = fonts[0]
+    fonts = fonts[1:]
+
+    base_glyphset = glyphsets[0]
+    glyphsets = glyphsets[1:]
+
+    glyphs = base_font.reader.getGlyphSet().keys()
+    for glyph in glyphs:
+        # Check each font against the base font
+        for idx, glyphset in enumerate(glyphsets):
+            font = fonts[idx]
+            res = test([base_glyphset, glyphset], glyphs=[glyph], names=names)
+            points_compat = nodes_compatible(base_font, font, glyph)
+            comps_compat = components_compatible(base_font, font, glyph)
+            if all([not res, points_compat, comps_compat]):
+                continue
+            if not points_compat:
+                fix_starting_points(
+                    [base_glyphset, glyphset], base_font, font, glyph, names
+                )
+            if not comps_compat:
+                fix_component_order(base_font, font, glyph)
+            if res and any(i["type"] == "contour_order" for i in res[glyph]):
+                fix_contour_order([base_glyphset, glyphset], font, glyph, names)
+            if res:
+                for issue in res[glyph]:
+                    if issue["type"] in ["wrong_start_point", "node_incompatibility"]:
+                        fix_starting_points(
+                            [base_glyphset, glyphset], base_font, font, glyph, names
+                        )
+                    else:
+                        print("Cannot fix")
+                        print(issue)
+
+    print("Done!")
+
+
+if __name__ == "__main__":
+    main()