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@@ -15,6 +15,23 @@ To get zipcode info using `curl` and [`jq`](https://stedolan.github.io/jq/):
 curl --silent http://localhost:8080/zip/18101 | jq '.'
 ```
 
+# Response
+
+Your response will look something like this:
+
+```json
+{
+	"latitude": 40.602847,
+	"longitude": -75.47022,
+	"city": "Allentown",
+	"state": "PA"
+}
+```
+
+If the zipcode you request isn't in the database, you'll get a `404` status with an empty body.
+
+Add a `?distance=` parameter to your request to see how far away two zipcodes are. The response format will be the same as above with an additional `distance` key that contains info about the second zipcode as well as `miles` and `kilometers` keys. If the second zipcode can't be found, the `distance` key won't be included.
+
 # Data
 
 This project uses public-domain zipcode data from the [Zip Code Database Project](http://zips.sourceforge.net).