Latest, 16 Oct 2026:67 usersMove the mouse over the chart for any month
Ratings count
monthly, 2 months
Latest, 16 Oct 2026:6 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About Captain JSON - JSON Viewer & Formatter
Captain JSON: The Ultimate JSON Toolkit for Developers & QA Engineers
Format. Validate. Compare. Convert. Generate.
Stop jumping between multiple websites and tools just to work with JSON.
Captain JSON is an all-in-one browser extension packed with 20+ powerful JSON tools for developers, QA engineers, testers, automation engineers, and anyone who works with JSON every day.
From formatting and validation to smart comparison, JSONPath, jq, conversion, table views, JWT tools, and more β everything you need is available in one fast, modern workspace inside your browser.
π Why Captain JSON?
- 100% Offline βYour JSON stays on your device.
- Privacy First β No need to send sensitive payloads to online tools.
-Lightweight β Fast, focused, and built for everyday developer workflows.
-Blazing Fast β Optimized for large and deeply nested JSON documents.
-20+ Powerful Tools β Replace a collection of separate JSON websites with one extension.
-Developer Friendly β Keyboard shortcuts, fullscreen editing, undo/redo, file upload/download, and more.
Successfully tested with JSON files over 30 MB, with smooth editing, formatting, searching, validation, and comparison directly in your browser.
π οΈ Powerful JSON Toolkit
π JSON Compare
Compare JSON documents side-by-side and quickly understand what changed.
-Strict comparison
-Ignore whitespace differences
-Ignore object key order
-Auto-compare while typing
-Swap inputs
-Large JSON support
-Undo/Redo
-Fullscreen editing
Perfect for API response comparison, regression testing, contract testing, configuration comparison, and debugging.
β¨ JSON Pretty Print
Turn messy JSON into clean, readable, developer-friendly output.
-Pretty print
-Minify
-Sort keys
-Remove null values
-Remove empty values
-Remove duplicate keys
-Custom indentation
-Live formatting
β JSON Validator
Find malformed JSON quickly with precise error information.
-Syntax validation
-Line and column information
-Error highlighting
-Clear error messages
-Fast validation
-Large JSON support
π JSONPath Query
Explore complex JSON and extract exactly the data you need.
-JSONPath expressions
-Interactive JSON tree
-Click-to-generate JSONPath
-Search by key or value
-Query history
-Built-in examples
-Copy and download results
βοΈ JQ Query
Filter, transform, and reshape JSON using familiar jq-style expressions.
-Field selection
-Array indexing
-Filtering
-Mapping
-Sorting
-Grouping
-Length calculations
-Basic transformations
-Live preview
π JSON to Table
Turn complex nested JSON into an easy-to-explore table.
-Nested objects
-Arrays
-Mixed structures
-Relational table view
-Data exploration
π JSON Escape / Unescape
Instantly escape JSON for use inside source code, SQL, configuration files, and strings β or restore it back to readable JSON.
π JSON Converter
Convert between popular data formats without leaving your browser.
-JSON β XML
-JSON β YAML
-XML β JSON
-YAML β JSON
-Automatic format detection
-Input/output swapping
-Copy and download
π JWT Tools
Decode and inspect JWT tokens, and work with JWT payloads directly from your browser.
β‘ Built for Real Developer Workflows
Captain JSON is designed for the situations developers and QA engineers encounter every day:
-Compare API responses
-Debug REST API payloads
-Validate request/response bodies
-Analyze microservice communication
-Beautify logs
-Test API contracts
-Investigate regression issues
-Extract API data with JSONPath
-Filter payloads with jq
-Convert JSON to YAML or XML
-Analyze deeply nested responses
-Inspect configuration files
-Prepare JSON for documentation
-Work with large JSON payloads
-Decode JWT tokens
π» A Better JSON Workflow
Why keep 10 different JSON websites*open when one extension can do it all?
Captain JSON brings your essential JSON workflow into a single, focused browser experience with no unnecessary tabs, no repetitive copy-pasting between websites, and no need to upload sensitive data to third-party services.
One extension. 20+ tools. Zero unnecessary tabs.
Whether you're building APIs, testing applications, developing automation frameworks, debugging microservices, working with cloud configurations, or simply dealing with complex JSON every day:
Captain JSON helps you work with JSON faster, smarter, and more privately.
Your JSON. Your browser. Your tools.
Format. Validate. Compare. Convert. Generate.
Install Captain JSON and make JSON work easier.