How to choose JSON validation tools
The right page depends on the data you need to check. A single JSON document needs a syntax check, a document with rules needs schema validation, and JSON Lines needs one check per nonblank line. Each page reports the details that match that input.
How to validate JSON
Start with the shape of the data. These pages are part of JSON Tools, and they cover three checking jobs.
- Choose JSON Validator & Formatter for one JSON document, JSON Schema Validator for a document plus a schema, or JSONL Validator & Formatter for JSON Lines.
- Paste or enter the data and, where requested, the schema.
- Check the result for parse errors, schema violations, or malformed records.
- Format, inspect, copy, or download the result if that page provides the output.
Which JSON validator fits your input?
- One JSON document: Use JSON Validator & Formatter to check syntax, format parsed content, inspect a tree view, and copy or download the processed result.
- A JSON document and rules: Use JSON Schema Validator when a schema defines the fields and values the document must satisfy. Select draft 04, 06, 07, 2019-09, or 2020-12. The result shows each violation with its path and line or column position.
- JSONL or NDJSON: Use JSONL Validator & Formatter when each nonblank line is its own JSON record. It reports parser details for malformed records, summarizes record types, and exports compact JSONL or indented review output.
What each JSON validation tool reports
Syntax validation checks if the text can be parsed as JSON. Formatting changes the display of parsed content, and the tree view shows its structure. For example, JSON Validator & Formatter can turn compact input into review output:
{"name":"Mira","active":true}
{
"name": "Mira",
"active": true
}Schema validation checks a second set of rules. A document can have valid JSON syntax and still violate the supplied schema. JSON Schema Validator keeps the syntax result separate from schema violations and gives each violation an exact path and line or column location.
JSONL validation reads each nonblank line independently. A malformed record is identified by its own parser details, and the other records remain separate entries in the review. Use the JSONL page for newline-delimited records. A single object or array is a different input shape.
Where JSON validation comes up
- A developer receives a compact API response, inspects its tree with JSON Validator & Formatter, and copies formatted content into a ticket.
- A team checks a configuration document against an agreed schema and uses JSON Schema Validator to locate a failing field by path and line or column.
- An analyst reviews an NDJSON export, finds malformed lines with JSONL Validator & Formatter, and downloads an indented version for discussion.
Frequently asked questions
Which tool should I use to validate JSON syntax?
Use JSON Validator & Formatter for a single JSON document when you need syntax validation, formatted output, or a tree view.
How do I validate JSON against a schema?
Use JSON Schema Validator, supply the JSON document and schema, and choose the applicable draft. The result separates invalid JSON syntax from schema violations.
How do I check JSONL or NDJSON lines?
Use JSONL Validator & Formatter. It parses each nonblank line independently and shows parser details for malformed records.
What happens when JSON syntax is invalid?
The validator reports invalid JSON syntax. JSON Schema Validator keeps that result separate from schema violations, and JSONL Validator & Formatter identifies malformed records with parser details.