diff --git a/2015-python/solutions/day_12.py b/2015-python/solutions/day_12.py
new file mode 100644
index 0000000..0cdedc3
--- /dev/null
+++ b/2015-python/solutions/day_12.py
@@ -0,0 +1,38 @@
+import json
+import re
+from solutions import BaseSolution
+
+
+class Solution(BaseSolution):
+    input_file = "12.txt"
+
+    def __str__(self):
+        return "Day 12: JSAbacusFramework.io"
+
+    def parse_input(self, data):
+        return data.strip()
+
+    def solve(self, puzzle_input):
+        digits = re.compile(r"-?\d+")
+        return sum(map(int, re.findall(digits, puzzle_input)))
+
+    def solve_again(self, puzzle_input):
+        def nodesum(node):
+            if isinstance(node, int):
+                return node
+            if isinstance(node, str):
+                return 0
+            if isinstance(node, list):
+                return sum(nodesum(i) for i in node)
+            if isinstance(node, object):
+                if "red" in node.values():
+                    return 0
+                return sum(nodesum(i) for i in node.values())
+
+        nodes = json.loads(puzzle_input)
+        return nodesum(nodes)
+
+
+if __name__ == "__main__":
+    solution = Solution()
+    solution.show_results()
diff --git a/2015-python/tests/test_day_12.py b/2015-python/tests/test_day_12.py
new file mode 100644
index 0000000..5583629
--- /dev/null
+++ b/2015-python/tests/test_day_12.py
@@ -0,0 +1,39 @@
+import unittest
+
+from solutions.day_12 import Solution
+
+
+class Day12TestCase(unittest.TestCase):
+    def setUp(self):
+        self.solution = Solution()
+        self.puzzle_input = self.solution.parse_input(
+            """
+        <REPLACE ME>
+        """
+        )
+
+    def test_parse_puzzle_input(self):
+        data = """
+        <REPLACE ME>
+        """.strip()
+        assert self.solution.parse_input(data) == "<REPLACE ME>"
+
+    def test_solve_first_part(self):
+        assert self.solution.solve("[1,2,3]") == 6
+        assert self.solution.solve('{"a":2,"b":4}') == 6
+        assert self.solution.solve("[[[3]]]") == 3
+        assert self.solution.solve('{"a":{"b":4},"c":-1}') == 3
+        assert self.solution.solve('{"a":[-1,1]}') == 0
+        assert self.solution.solve('-1,{"a":1}]') == 0
+        assert self.solution.solve("{}") == 0
+        assert self.solution.solve("[]") == 0
+
+    def test_solve_second_part(self):
+        assert self.solution.solve_again("[1,2,3]") == 6
+        assert self.solution.solve_again('[1,{"c":"red","b":2},3]') == 4
+        assert self.solution.solve_again('{"d":"red","e":[1,2,3,4],"f":5}') == 0
+        assert self.solution.solve_again('[1,"red",5]') == 6
+
+
+if __name__ == "__main__":
+    unittest.main()