Your JSON Is Valid... Until It's Not: Common Parse Errors and How to Fix Them

Short summary

JSON parsers fail on valid-looking syntax like trailing commas, smart quotes from word processors or ChatGPT, unquoted keys, UTF-8 BOMs at file start, and single quotes instead of double quotes—all allowed in JavaScript but rejected by strict JSON spec (RFC 8259). The article walks through each error with before/after code examples and the exact fix. When debugging parse errors, use a formatter that pinpoints the exact line and column of the first syntax violation.

• •Trailing commas, smart quotes, unquoted keys, UTF-8 BOMs, and single quotes cause JSON parse failures
• •These patterns work in JavaScript but violate RFC 8259 JSON specification
• •Use JSON formatters with precise error location reporting to debug faster than manual inspection

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