informational guide · Updated 2026-08-12
Common JSON errors
Fix trailing commas, single quotes, comments, and encoding issues in JSON payloads.
Trailing commas
Trailing commas after the last property are valid in modern JavaScript, not in JSON.
Quotes
Keys and strings must use double quotes. Single quotes fail strict parsers.
Comments
JSON does not support comments. Move notes outside the document or use a JSONC toolchain knowingly.
Encoding
Ensure UTF-8 encoding and proper escaping for control characters. Format, then validate on Utila to locate issues faster.
Primary tool: JSON Validator
