diff --git a/tools/api_changes_generator.py b/tools/api_changes_generator.py
new file mode 100644
index 000000000000..f58517c8d155
--- /dev/null
+++ b/tools/api_changes_generator.py
@@ -0,0 +1,124 @@
+import ast
+import inspect
+import logging
+from pathlib import Path
+import tokenize
+
+import matplotlib
+from matplotlib import cbook
+
+_log = logging.getLogger(__name__)
+
+
+def node_match(node, name, **kwargs):
+    return (type(node).__name__ == name
+            and all(getattr(node, k) == v for k, v in kwargs.items()))
+
+
+def bind_arguments(func, node, qualname):
+    ba = inspect.signature(func).bind(
+        *node.args, **{k.arg: k.value for k in node.keywords})
+    for k, v in [*ba.arguments.items()]:
+        if node_match(v, "NameConstant"):
+            ba.arguments[k] = v.value
+        if node_match(v, "Num"):
+            ba.arguments[k] = v.n
+        elif node_match(v, "Str"):
+            ba.arguments[k] = v.s
+        else:
+            _log.warning(f"In {qualname} line {node.lineno}, "
+                         f"unsupported argument: {v}")
+    return ba
+
+
+def generate_apichanges_deprecated(name, arguments):
+    obj_type = arguments["obj_type"]
+    s = [f"The {name} {obj_type} is deprecated."]
+    if arguments["alternative"]:
+        s += [f"Use {arguments['alternative']} instead."]
+    return "  ".join(s)
+
+
+def generate_apichanges_warn_deprecated(name, arguments):
+    try:
+        return cbook.deprecation._generate_deprecation_warning(**arguments)
+    except TypeError:
+        return "FIXME"
+
+
+class DeprecationDetector(ast.NodeVisitor):
+    def __init__(self, module_name):
+        super().__init__()
+        self._qualname_parts = [module_name]
+        self.deprecateds = []
+        self.warn_deprecateds = []
+
+    current_qualname = property(lambda self: ".".join(self._qualname_parts))
+
+    def _visit_class_or_function(self, node):
+        self._qualname_parts.append(node.name)
+        obj_type = {"ClassDef": "class", "FunctionDef": "function"}[
+            type(node).__name__]
+        for decorator in node.decorator_list[::-1]:
+            if node_match(decorator, "Name", id="property"):
+                obj_type = "property"
+            if node_match(decorator, "Call"):
+                func = decorator.func
+                if (node_match(func, "Name", id="deprecated")
+                        or node_match(func, "Attribute", attr="deprecated")):
+                    ba = bind_arguments(cbook.deprecated, decorator,
+                                        self.current_qualname)
+                    ba.arguments.setdefault("obj_type", obj_type)
+                    ba.apply_defaults()
+                    self.deprecateds.append(
+                        (self.current_qualname, ba.arguments))
+        super().generic_visit(node)
+        self._qualname_parts.pop()
+
+    visit_ClassDef = visit_FunctionDef = _visit_class_or_function
+
+    def visit_Call(self, node):
+        if (node_match(node.func, "Name", id="warn_deprecated")
+                or node_match(node.func, "Attribute", attr="warn_deprecated")):
+            ba = bind_arguments(cbook.warn_deprecated, node,
+                                self.current_qualname)
+            self.warn_deprecateds.append((self.current_qualname, ba.arguments))
+
+
+def main():
+    root = Path(matplotlib.__file__).parent.parent
+    deprecateds = []
+    warn_deprecateds = []
+    for path in sorted(root.glob("**/*.py")):
+        parts = path.relative_to(root).with_suffix("").parts
+        if parts[-1] == "__init__":
+            parts = parts[:-1]
+        module_name = "".join(f".{part}" for part in parts[1:])  # Drop pkg name.
+        with tokenize.open(path) as file:
+            source = file.read()
+        tree = ast.parse(source)
+        dd = DeprecationDetector(module_name)
+        dd.visit(tree)
+        deprecateds.extend(dd.deprecateds)
+        warn_deprecateds.extend(dd.warn_deprecateds)
+    by_version = {}
+    for name, arguments in deprecateds:
+        by_version.setdefault(arguments["since"], []).append((name, arguments))
+    for version, deprecateds in sorted(by_version.items()):
+        print()
+        print(f"Since {version}:")
+        for name, arguments in deprecateds:
+            print(generate_apichanges_deprecated(name, arguments))
+    by_version = {}
+    for name, arguments in warn_deprecateds:
+        by_version.setdefault(arguments["since"], []).append((name, arguments))
+    # for version, warn_deprecateds in sorted(by_version.items()):
+    for version, warn_deprecateds in by_version.items():
+        print()
+        print(f"Since {version}:")
+        for name, arguments in warn_deprecateds:
+            print(generate_apichanges_warn_deprecated(name, arguments))
+
+
+if __name__ == "__main__":
+    main()