I'm getting the following JSONException when JSON serializing a Map of generic Objects which contains a Url object deeply nested within.

System.JSONException: Type unsupported in JSON: common.apex.methods.ApexUrl$URIImpl

It looks like Apex doesn't support JSON serializing the Url class because I was able to replicate the error in Anonymous Apex simply with JSON.serialize(new Url('https://www.google.com'));.

What would be the best way to serialize my object without having to refactor my Url properties to String? For some context, I'm serializing the Map described in this question.

  • Can you add sample JSON? Apr 18, 2018 at 22:07
  • @PranayJaiswal I'm trying to serialize a Url object to JSON, so I don't have any sample JSON to give. Apr 18, 2018 at 22:09
  • 1
    @KevinVizcarra hes talking about the object you're trying to serialize
    – EricSSH
    Apr 18, 2018 at 22:11
  • 1
    You're going to have to change the properties to String. Why do you want to leave them as URL? You seem to be having a bit of an X-Y Problem here.
    – Adrian Larson
    Apr 18, 2018 at 22:15
  • I tried debugging the URL's toString method. It looks like that object was not designed to be serialised. If you force it to serialize it will form a malformed JSON. .-----> System.debug(JSON.serialize(new Url('google.com').toString())); Apr 18, 2018 at 22:17

1 Answer 1


You'll have to do some refactoring, but this is a pretty clean solution:

public class DataHandler {
    public string urlAsString { get; set; }
    public transient Url urlAsUrl { get { return new Url(urlAsString); } set { urlAsString = value.toExternalForm(); }}
DataHandler x = new DataHandler();
x.urlAsUrl = new Url('https://www.google.com');

The "transient" bit keeps JSON.serialize from handling the Url data, but it will serialize the string just fine.

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