Node.js errors

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Top tools (local-only)

• JSON Validator
• JSON Repair
• YAML Validator
• CSV Validator
• XML to JSON
• Base64 Encode/Decode
• URL Encode/Decode
• JWT Decoder

JSON parse / deserialize errors

Most issues are not “bad JSON” but wrong content (HTML), truncation, extra characters, invalid escapes, or encoding.

• Bad control character in string literal in JSON at position
• JSON.parse: expected property name or '}' at line 1 column 2 of the JSON data
• JSON.parse: unexpected character at line 1 column 1 of the JSON data
• JSON.parse: unexpected end of data at line 1 column 1 of the JSON data
• JSON.parse: unterminated string at line 1 column 10 of the JSON data
• SyntaxError: Bad control character in string literal in JSON at position 10
• SyntaxError: Unexpected end of JSON input
• SyntaxError: Unexpected non-whitespace character after JSON at position 1
• SyntaxError: Unexpected number in JSON at position 10
• SyntaxError: Unexpected string in JSON at position 10
• SyntaxError: Unexpected token ' in JSON at position 0
• SyntaxError: Unexpected token , in JSON at position 0
• SyntaxError: Unexpected token / in JSON at position 0
• SyntaxError: Unexpected token < in JSON at position 0
• SyntaxError: Unexpected token \\ in JSON at position 0
• SyntaxError: Unexpected token ] in JSON at position 0
• SyntaxError: Unexpected token E in JSON at position 0
• SyntaxError: Unexpected token F in JSON at position 0
• SyntaxError: Unexpected token H in JSON at position 0
• SyntaxError: Unexpected token I in JSON at position 0
• SyntaxError: Unexpected token N in JSON at position 0
• SyntaxError: Unexpected token o in JSON at position 1
• SyntaxError: Unexpected token P in JSON at position 0
• SyntaxError: Unexpected token S in JSON at position 0
• SyntaxError: Unexpected token T in JSON at position 0
• SyntaxError: Unexpected token u in JSON at position 0
• SyntaxError: Unexpected token U in JSON at position 0
• SyntaxError: Unexpected token } in JSON at position 0
• SyntaxError: Unexpected token ï in JSON at position 0
• SyntaxError: Unterminated string in JSON at position 10
• Unexpected end of JSON input
• Unexpected non-whitespace character after JSON at position
• Unexpected number in JSON at position
• Unexpected string in JSON at position
• Unexpected token ' in JSON at position 0
• Unexpected token , in JSON at position 0
• Unexpected token / in JSON at position 0
• Unexpected token < in JSON at position 0
• Unexpected token \\ in JSON at position 0
• Unexpected token ] in JSON at position 0
• Unexpected token o in JSON at position 1
• Unexpected token u in JSON at position 0
• Unexpected token } in JSON at position 0
• Unexpected token ï in JSON at position 0

Encoding / token errors (Base64, URL, JWT)

Encoded strings may contain secrets. Decode locally and normalize Base64URL/percent-encoding safely.

• Failed to execute 'atob' on 'Window': The string to be decoded is not correctly encoded.
• InvalidCharacterError: The string to be decoded is not correctly encoded
• InvalidCharacterError: The string to be decoded is not correctly encoded (base64url)
• JsonWebTokenError: invalid algorithm
• JsonWebTokenError: invalid signature
• JsonWebTokenError: invalid token
• JsonWebTokenError: jwt audience invalid
• JsonWebTokenError: jwt issuer invalid
• JsonWebTokenError: jwt malformed
• JsonWebTokenError: jwt must be provided
• JsonWebTokenError: jwt signature is required
• JsonWebTokenError: jwt subject invalid
• JsonWebTokenError: secret or public key must be provided
• NotBeforeError: jwt not active
• TokenExpiredError: jwt expired
• URIError: malformed URI sequence
• URIError: URI malformed

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