diff --git a/exercises/twelve-days/canonical-data.json b/exercises/twelve-days/canonical-data.json
new file mode 100644
index 0000000000..48b1675840
--- /dev/null
+++ b/exercises/twelve-days/canonical-data.json
@@ -0,0 +1,171 @@
+{
+  "exercise": "twelve-days",
+  "version": "1.0.0",
+  "comments": [
+    "JSON doesn't allow for multi-line strings, so all verses are presented ",
+    "here as arrays of strings. It's up to the test generator to join the ",
+    "lines together with line breaks."
+  ],
+  "cases": [
+    {
+      "description": "verse",
+      "cases": [
+        {
+          "description": "first day a partridge in a pear tree",
+          "property": "recite",
+          "startVerse": 1,
+          "endVerse": 1,
+          "expected": [
+            "On the first day of Christmas my true love gave to me, a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "second day two turtle doves",
+          "property": "recite",
+          "startVerse": 2,
+          "endVerse": 2,
+          "expected": [
+            "On the second day of Christmas my true love gave to me, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "third day three french hens",
+          "property": "recite",
+          "startVerse": 3,
+          "endVerse": 3,
+          "expected": [
+            "On the third day of Christmas my true love gave to me, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "fourth day four calling birds",
+          "property": "recite",
+          "startVerse": 4,
+          "endVerse": 4,
+          "expected": [
+            "On the fourth day of Christmas my true love gave to me, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "fifth day five gold rings",
+          "property": "recite",
+          "startVerse": 5,
+          "endVerse": 5,
+          "expected": [
+            "On the fifth day of Christmas my true love gave to me, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "sixth day six geese-a-laying",
+          "property": "recite",
+          "startVerse": 6,
+          "endVerse": 6,
+          "expected": [
+            "On the sixth day of Christmas my true love gave to me, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "seventh day seven swans-a-swimming",
+          "property": "recite",
+          "startVerse": 7,
+          "endVerse": 7,
+          "expected": [
+            "On the seventh day of Christmas my true love gave to me, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "eighth day eight maids-a-milking",
+          "property": "recite",
+          "startVerse": 8,
+          "endVerse": 8,
+          "expected": [
+            "On the eighth day of Christmas my true love gave to me, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "ninth day nine ladies dancing",
+          "property": "recite",
+          "startVerse": 9,
+          "endVerse": 9,
+          "expected": [
+            "On the ninth day of Christmas my true love gave to me, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "tenth day ten lords-a-leaping",
+          "property": "recite",
+          "startVerse": 10,
+          "endVerse": 10,
+          "expected": [
+            "On the tenth day of Christmas my true love gave to me, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "eleventh day eleven pipers piping",
+          "property": "recite",
+          "startVerse": 11,
+          "endVerse": 11,
+          "expected": [
+            "On the eleventh day of Christmas my true love gave to me, eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "twelfth day twelve drummers drumming",
+          "property": "recite",
+          "startVerse": 12,
+          "endVerse": 12,
+          "expected": [
+            "On the twelfth day of Christmas my true love gave to me, twelve Drummers Drumming, eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        }
+      ]
+    },
+    {
+      "description": "lyrics",
+      "cases": [
+        {
+          "description": "recites first three verses of the song",
+          "property": "recite",
+          "startVerse": 1,
+          "endVerse": 3,
+          "expected": [
+            "On the first day of Christmas my true love gave to me, a Partridge in a Pear Tree.",
+            "On the second day of Christmas my true love gave to me, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the third day of Christmas my true love gave to me, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "recites three verses from the middle of the song",
+          "property": "recite",
+          "startVerse": 4,
+          "endVerse": 6,
+          "expected": [
+            "On the fourth day of Christmas my true love gave to me, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the fifth day of Christmas my true love gave to me, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the sixth day of Christmas my true love gave to me, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        },
+        {
+          "description": "recites the whole song",
+          "property": "recite",
+          "startVerse": 1,
+          "endVerse": 12,
+          "expected": [
+            "On the first day of Christmas my true love gave to me, a Partridge in a Pear Tree.",
+            "On the second day of Christmas my true love gave to me, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the third day of Christmas my true love gave to me, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the fourth day of Christmas my true love gave to me, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the fifth day of Christmas my true love gave to me, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the sixth day of Christmas my true love gave to me, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the seventh day of Christmas my true love gave to me, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the eighth day of Christmas my true love gave to me, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the ninth day of Christmas my true love gave to me, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the tenth day of Christmas my true love gave to me, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the eleventh day of Christmas my true love gave to me, eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.",
+            "On the twelfth day of Christmas my true love gave to me, twelve Drummers Drumming, eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree."
+          ]
+        }
+      ]
+    }
+  ]
+}
\ No newline at end of file