Unexpected end of JSON input

How browsers word it

Common causes

1. The body is empty

   A 204 No Content response, a failed request or a missing file gives an empty string, and parsing an empty string always fails.

   Input

   (empty)

   JSON Formatter says

   Nothing to parse. The input is empty

2. The text is only whitespace

   A body that holds just a newline or spaces fails the same way.

   Input

   JSON Formatter says

   Nothing to parse. The input is empty

3. The text was cut off where a value should be

   A dropped connection, a size limit or a file that was not saved completely can stop the text right after a colon or a comma.

   Input

   {"a":

   JSON Formatter says

   Unexpected end of input. A value is missing

4. The text was cut off inside a string

   If the cut falls inside a string, current engines report an unterminated string rather than this message.

   Input

   {"a": "hel

   JSON Formatter says

   Unterminated string. A closing double quote is missing

How to fix it

1. Log the raw response text and its length before parsing.
2. Check the status code. A 204 has no body, so skip .json() for it.
3. Compare Content-Length with what you received, and look for proxies or functions that limit the response size.
4. If you read a file, make sure it was written completely before it is parsed.