Learn JSON

Start here

• What is JSON?

  What JSON is for, the six kinds of value, and the rules that trip people up.

Basics

• JSON vs. JavaScript objects

  Why an object that works in JavaScript can fail as JSON, and how to convert between the two.

• Strings and escaping in JSON

  Double quotes, backslash escapes like \n, and the characters that must be escaped.

• Numbers and precision in JSON

  Why big IDs can lose digits, and why 0.1 + 0.2 isn't 0.3.

Fix an error

Each one shows what Chrome and Node.js say, so you can match the message you got.

• Trailing comma in JSONYou left a comma after the last itemExpected double-quoted property name in JSON
• Unexpected end of JSON inputThe JSON got cut off partway, or the text is emptyUnexpected end of JSON input
• Missing comma in JSONTwo items have no comma between themExpected ',' or '}' after property value in JSON
• Single quotes in JSONKeys or text are in 'single quotes'Expected property name or '}' in JSON
• Unquoted keys in JSONA key has no quotes around itExpected property name or '}' in JSON
• Text before or after the JSONOther text or Markdown fences came along with the JSONUnexpected token 'H'
• Missing curly braces in JSONYou copied a few keys and values without the { } around themUnexpected non-whitespace character after JSON at position 6
• Missing square brackets in JSONSeveral values with commas, but no [ ] around themUnexpected non-whitespace character after JSON at position 33
• Comments in JSONThe JSON has // or /* */ comments in itExpected property name or '}' in JSON
• True, False and None in JSONIt uses Python's True, False or NoneUnexpected token 'T'
• Curly quotes in JSONThe quotes are curly “ ” instead of straightExpected property name or '}' in JSON
• Unterminated string in JSONA string is missing its closing quoteBad control character in string literal in JSON
• Line break inside a JSON stringA string has a real line break in itBad control character in string literal in JSON
• Missing colon in JSONA key has no colon before its valueExpected ':' after property name in JSON
• JSON inside JavaScript or Python codeThe JSON is still inside JavaScript or Python codeUnexpected token 'c'
• JSON inside a curl commandThe JSON is still inside a curl commandUnexpected token 'c'

JSON in n8n

• JSON in n8n

  How nodes pass data as items, what the json and binary keys hold, pinned data, and workflow JSON.