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Validate JSON syntax and report errors with line numbers without reformatting. Use when only correctness matters; for auto-fix and formatting use json-formatter. Input: JSON text ≤10MB. Returns valid/invalid + error location. 100% client-side.
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Real-time JSON validation with syntax checking, structural analysis (key counts, depth, array sizes), and tree view for navigating complex documents. Includes path breadcrumb navigation, schema validation against JSON Schema drafts, and actionable suggestions for common errors.
JSON is everywhere but even minor syntax errors (missing commas, trailing commas, unquoted keys) cause parsing failures. Provides instant feedback and structured analysis to debug complex JSON documents efficiently.
This tool is part of the DevStackIO platform — a collection of free online developer tools from DevStackIO. Browse more free developer resources on DevStackIO.
All developers working with JSON - from beginners learning the format to experienced engineers debugging large API payloads or configuration files.
Paste or type JSON into the editor; validation runs in real-time with error highlighting on the problematic line and column
Review the structural analysis panel showing key count, maximum depth, array counts, and data size statistics
Use the tree view to collapse/expand nested nodes; click any node to see its path in the breadcrumb trail
Optionally paste a JSON Schema into the schema panel to validate the JSON against the schema
Apply suggested fixes from the suggestions panel for common errors like trailing commas or unquoted keys
Use the "Format" button to pretty-print the JSON after fixing errors; the tree view updates automatically
Input: {"name": "Alice","age": 30,} (trailing comma) -> Error: "Unexpected token } at line 1, column 30. Suggestion: Remove trailing comma after "age": 30"Input: {"users":[{"id":1},{"id":2}]} -> Analysis: Keys: id, users | Depth: 3 | Arrays: 1 (users: 2 items) | Valid: trueDoes it validate against JSON Schema drafts?
Yes, it supports Draft-04, Draft-06, Draft-07, and 2020-12 schema versions.
Can it handle very large JSON files (10MB+)?
Yes, but performance may degrade; structural analysis is optimized for documents up to several MB.
What types of errors does it catch?
Syntax errors, duplicate keys, encoding issues, and schema violations including type mismatches and missing required fields.
Does the breadcrumb path help with nested validation errors?
Yes, clicking an error highlights the exact path in the tree view and shows the navigation breadcrumb.
Authoritative specifications, standards, and in-depth reading for JSON Validator.
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