JSONLint
Validate and format JSON with error highlighting.
Open the official app on jsonlint.com
This tool is hosted by its maintainers. Click below to open jsonlint.com in a new tab — it's their official demo.
Browse validators tools →What's next with JSONLint?
Choose how you want to get started.
Use it free
Open the official tool or demo — no account needed.
Self-host it
Run the open-source version on your own infrastructure.
What is JSONLint?
JSONLint is an open-source tool designed to validate and reformat JSON data, ensuring its structural integrity and readability. It addresses common issues such as syntax errors, missing commas, or mismatched brackets that can disrupt data interchange between systems. Developers, API integrators, and data scientists use JSONLint to debug malformed JSON, streamline data processing, and maintain consistency in applications reliant on JSON for communication. The tool solves the problem of human or machine-generated JSON errors by providing immediate feedback and organizing data into a clean, standardized format. Its lightweight design and simplicity make it accessible for both beginners and experienced professionals working with JSON in diverse environments.
How it works
JSONLint is a validator and reformatter for JSON, a lightweight data-interchange format. It enables users to check the syntax of JSON data, identify errors, and restructure it for clarity. The tool is particularly useful for developers and data engineers who rely on JSON for transmitting data between systems. By ensuring JSON validity, JSONLint helps prevent errors in data parsing and integration processes. JSONLint performs real-time syntax validation, highlighting issues such as unclosed brackets, missing commas, or invalid Unicode characters. It also reformats JSON to improve readability, aligning indentation and structure for easier debugging.
How to use it
- 1Paste or type JSON data into the editor. 2. Click 'Validate' to check for syntax errors. 3. Review error messages or use 'Format' to restructure the JSON. 4. Export the cleaned data or copy the corrected version. Practical tips include using JSONLint before API requests to ensure data compatibility, or during development to catch errors early in the workflow.
What it can do
- json validator
Use cases
Assumptions and limitations
Assumptions
- source: https://jsonlint.com/
- license: Open source
- privacy: Opens an external demo
Limitations
- Limited support for advanced JSON features like comments or custom data types
- No built-in schema validation against JSON Schema definitions
- Basic error messages may lack context for complex nested structures
- Does not handle JSON streaming or large files efficiently
- No collaboration features for team-based JSON development
Understanding the result
Validate and format JSON with error highlighting.
Tool details
- Clearly flagged when a network request is needed.
- No account, no sign-up, and no tracking of your content.
- Powered by (MIT).
- Built with
- (https://jsonlint.com/)
- License
- MIT
- Runs locally
- No — requires a network request
- Verification
- Not yet verified
- Input
- Query
- Output
- Text
Built with https://jsonlint.com/. OpenToolVault provides the discovery and browser interface while crediting the original project maintainers.
- Built with
- License
- MIT
Open-source project
OpenToolVault is an independent directory. We are not affiliated with or endorsed by this project.
References
- / — GitHub Repository
Upstream project · GitHub
Frequently asked
What does JSONLint do?
JSONLint validates JSON syntax to identify errors like missing commas or unclosed brackets. It also reformats JSON data to improve readability by standardizing indentation and structure. This ensures data is both functionally correct and easier to debug.
How does JSONLint work?
JSONLint parses the input JSON to check for syntax compliance with the JSON standard. It uses a recursive approach to validate nested structures and reports errors at their exact locations. The reformatter applies consistent indentation and line breaks to enhance human readability without altering the data's logical structure.
How do I format JSON with JSONLint?
Paste your JSON into the editor, then click 'Format'. The tool will restructure the data with uniform indentation and line breaks. For example, a poorly formatted JSON like {"key":"value"} will be transformed into { "key": "value" } for clearer readability.
How does JSONLint compare to JSON Schema validators?
JSONLint focuses on basic syntax validation, while JSON Schema validators enforce structural rules defined in a schema. JSONLint is ideal for quick error checks, whereas JSON Schema tools are better for enforcing specific data formats in complex applications.
What should I do if JSONLint shows an error?
Review the error message, which indicates the line and nature of the issue. Common fixes include adding missing commas, correcting bracket placement, or escaping special characters. For example, an error about 'unexpected end of JSON' usually means a missing closing brace or quotation mark.