JSON Formatter, Validator & Diff Comparison
Format, validate, repair, and compare JSON structures client-side with syntax error pointers and side-by-side diffing.
Formatted JSON Output
About this tool
How to use it
- Paste your raw JSON text directly into the input textarea.
- Choose your preferred indentation style (2 spaces, 4 spaces, Tab, or Minified).
- Optionally check 'Sort Object Keys (A-Z)' to alphabetize key orders for uniform git commits.
- Switch to 'Diff & Compare' mode to inspect structural property changes between two JSON payloads.
Why it matters
Unformatted minified JSON from production APIs or database dumps is difficult for humans to read and review. Syntax errors (such as trailing commas or unquoted keys) break automated CI/CD pipelines and web application parsers.
When to use it
Use this formatter when debugging REST API responses, configuring package.json or tsconfig.json files, validating webhook payloads, or comparing staging vs production JSON configurations.
Good to know
All parsing is performed using native JavaScript JSON.parse(). No data is sent over the network, ensuring zero exposure of sensitive client identifiers or authorization tokens.
Common questions
Why does JSON fail on trailing commas?
The official JSON specification (RFC 8259) strictly forbids trailing commas in arrays and objects. While modern JavaScript allows them, standard JSON parsers will throw a syntax error.
What is the difference between 2-space and minified JSON?
2-space indentation adds newlines and indentation for human readability. Minified JSON strips all non-essential whitespace and line breaks, reducing file size and network bandwidth by 20% to 40%.
How does the JSON Diff work?
The diff engine flattens nested objects into dot-notation paths (e.g. 'data.user.email') and performs deep property comparison, identifying additions, deletions, and modified values.
Are my API tokens and passwords private?
Yes. This tool operates 100% in your local browser runtime. No JSON payloads are ever transmitted, saved, or uploaded to any external server.