Fix "Unexpected non-whitespace character after JSON"

JavaScript / Python · JSON error

By JSON Wallet Editorial Team · August 31, 2026

Unexpected non-whitespace character after JSON dataSyntaxError: Unexpected non-whitespace character after JSON at position NExtra data: line N column N (char N)

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What causes it

A JSON document must contain exactly one top-level value. This error (Python calls it Extra data) means the parser successfully read a complete value and then hit more content that should not be there. Common causes:

Concatenated objects — {"a":1}{"b":2} with nothing joining them. Wrap them in an array and add a comma.
Newline-delimited JSON (NDJSON) — one object per line. That is a valid stream format, but you must parse it line by line, not all at once.
A stray character after the closing bracket — a duplicated brace, a trailing log line, or copy-paste leftovers.

How to fix it

Look at the position/column — the extra content starts right after the first complete value.
If you have multiple objects, wrap them in [ ] and separate them with commas.
If it is NDJSON, split on newlines and JSON.parse() each line separately.
Paste it into JSON Wallet to see exactly where the first value ends and the extra data begins.

Before and after

Broken:

{"a": 1}
{"b": 2}

Fixed:

[
  {"a": 1},
  {"b": 2}
]

Want to fix your own JSON instead of the example? Open the editor, paste it in, and click Repair — it runs entirely in your browser.

Frequently asked questions

What is NDJSON and why does it cause this?

Newline-delimited JSON puts one JSON object per line. It is a streaming format, so a single JSON.parse() call over the whole thing fails after the first line. Parse each line individually.

How do I combine multiple objects into one document?

Wrap them in an array and separate them with commas: [{"a":1}, {"b":2}]. Then it is a single valid JSON value.

Related JSON errors

Fix "Unexpected token in JSON at position N"

The most common JSON.parse() error. It means the parser hit a character it did not expect — usually HTML, an already-parsed object, or a stray token.

Fix "Unexpected end of JSON input"

The parser reached the end of the text while still expecting more — an empty response, a truncated payload, or an unclosed bracket or quote.

For a full reference of JSON mistakes, read Common JSON errors and how to fix them.