JSON Error Messages, Explained and Fixed

Every JSON parse error follows a pattern - once you can read the message, the fix is usually one line. Paste your JSON below to locate the error, or jump to the guide for the exact message you are seeing.

{"find": "error"}paste your JSON below

JavaScript

Unexpected token < in JSON at position 0 Unexpected end of JSON input Unexpected token 'o', "[object Object]" is not valid JSON SyntaxError: "..." is not valid JSON TypeError: Converting circular structure to JSON

JavaScript (Firefox)

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Python

json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)json.decoder.JSONDecodeError: Extra data

Python / JavaScript

Expecting property name enclosed in double quotes NaN / Infinity is not valid JSON

All languages

Unexpected token ''' - single quotes in JSON Trailing comma in JSON / Unexpected token }Comments in JSON: Unexpected token /Duplicate keys in JSON: which value wins?JSON fails to parse: BOM / invisible character at position 0

JavaScript / Python

Unterminated string in JSON

Java

com.google.gson.JsonSyntaxException: MalformedJsonException com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException

Go

invalid character '<' looking for beginning of value

PHP

PHP json_decode returns NULL

Rust

serde_json: expected value / missing field errors

Ruby

JSON::ParserError: unexpected token at ...

C#

System.Text.Json.JsonException: 'x' is an invalid start of a value

Swift

Swift DecodingError: keyNotFound / typeMismatch / valueNotFound

PostgreSQL

ERROR: invalid input syntax for type json

MySQL

ERROR 3140: Invalid JSON text