The JSON specification (RFC 8259) requires strict syntax compliance. Unlike relaxed formats like JavaScript object literals or YAML, JSON parsers fail immediately upon encountering the slightest formatting irregularity. This JSON validator analyzes your payload, verifies RFC compliance, and provides the exact line and column location when a syntax error occurs.
Top Causes of JSON Parse Failures
- Trailing Commas: Adding a comma after the final key-value pair in an object or the last element of an array (for example,
{"a": 1,}) is invalid in standard JSON. - Single Quotes: RFC 8259 requires double quotation marks (
") for all strings and key names. Using single quotes ('key') results in an immediate parse error. - Unquoted Keys: While JavaScript allows unquoted object keys (
{name: "value"}), JSON mandates double quotes for all property identifiers. - Unescaped Control Characters: Literal newlines, carriage returns, and tabs inside string values must be escaped (
\n,\t). - Comments: Standard JSON does not permit single-line (
//) or multi-line (/* */) comments.
Error Coordinates: Line and Column Resolution
When a parse failure occurs in a thousand-line payload, a generic "Unexpected token" message is unhelpful. This validator calculates character offsets and displays the exact line number and column position, letting you locate and repair the syntax defect directly in the editor.
Related JSON Utilities
After validating your payload, continue processing with related tools:
- JSON Formatter: Clean and indent valid JSON.
- JSON Minifier: Strip whitespace for network transport.
- JSON Compare: Compare two JSON payloads side by side.
- JSON to Zod: Generate runtime schema validation rules.