Web APIs required for Multipart requests

If you want to use the multipart serializer option you need to ensure that following Web APIs are implemented in the web view:

• Blob API
• FileReader API
• TextEncoder API
• FormData API

If FormData.entries() is not implemented on your target audience's devices (you can check on caniuse.com), you can also use a ponyfill which is shipped with this plugin e.g. new cordova.plugin.http.ponyfills.FormData(). But be aware that these FormData instances are meant to be used for this plugin only. If you try to submit them via XMLHttpRequest or Fetch API, it won't work.