PerfectJSON
What PerfectJSON is
PerfectJSON is a free browser-based tool for formatting, validating, editing, comparing, and converting JSON. It can format or minify JSON and validate it against RFC 8259, RFC 7159, RFC 4627, and ECMA-404, identifying errors by line and column. Its one-click Auto-fix can repair trailing commas, single quotes, unquoted keys, comments, and unbalanced brackets.
For editing, PerfectJSON offers tree and table views, raw text editing with live highlighting, and a side-by-side diff viewer. It can convert JSON to YAML, CSV, plain text, formatted JSON, or minified JSON, with options to copy or download results. A lossless parser preserves large numbers and 64-bit IDs above 9007199254740991 through formatting and editing.
Parsing, validation, formatting, comparison, and conversion run locally in the browser. Edited JSON is not uploaded; documents and preferences are stored in browser local storage. PerfectJSON requires no account and supports current Chrome, Firefox, Safari, and Edge on desktop and mobile when JavaScript is enabled. The site uses Google Analytics and Google AdSense, which it says do not receive edited JSON contents.
Who it suits
PerfectJSON suits developers who work with JSON, including people handling API payloads, access tokens, and configuration files. It is also a fit for anyone who wants browser-based editing, comparison, validation, or conversion without creating an account.
What it does well
- Free to use with no accounts or usage limits.
- Validates against four listed JSON specifications with line and column errors.
- Auto-fix handles several common JSON syntax issues.
- Supports tree, table, and raw text editing.
- Processes JSON locally and does not upload edited content.
- Preserves large numbers and 64-bit IDs while formatting and editing.
What to know first
- Requires JavaScript to be enabled in a supported browser.
- The free service is supported by display ads.
- No JSONPath, jq, or batch processing.
Limits
The Free plan costs nothing, has no usage limits, and is supported by display ads. The service is provided as is, without warranties, and the maker does not guarantee uninterrupted or error-free operation.
Plans
| Plan | Billed and limits | Price |
|---|---|---|
| Free | Free of charge · No accounts · No usage limits · Supported by display ads | Free |
As perfectjson.com lists them, read 7 Oct 2026. The maker's own page has the final word.
Getting started
- Open the PerfectJSON website in a current version of Chrome, Firefox, Safari, or Edge.
- Enable JavaScript in the browser.
- Paste or edit JSON in the browser-based tool; no account is required.
Verdict
Choose PerfectJSON for browser-based JSON editing, validation, comparison, and conversion, especially when preserving large numeric values matters. Look elsewhere if you need JSONPath or jq queries, batch processing, or a service without display ads.
Questions
Does PerfectJSON cost anything?
It is free of charge. The Free plan costs nothing and has no usage limits.
Do I need an account?
No account is required.
Which platforms and browsers does it support?
It is a web tool that supports current Chrome, Firefox, Safari, and Edge on desktop and mobile, with JavaScript enabled.
Does PerfectJSON upload edited JSON?
No. Parsing, validation, formatting, comparison, and conversion run locally in the browser, and edited JSON is not uploaded.
Does it support JSON comparison and schema validation?
It includes a side-by-side JSON diff viewer and validates against RFC 8259, RFC 7159, RFC 4627, and ECMA-404.
Who makes PerfectJSON?
The listed facts do not identify a maker.
Facts from PerfectJSON's own pages
- Auto-fix
- Its one-click Auto-fix can repair trailing commas, single quotes, unquoted keys, comments and unbalanced brackets. · perfectjson.com, 7 Oct 2026
- Browser support
- It supports current versions of Chrome, Firefox, Safari and Edge on desktop and mobile, with JavaScript enabled. · perfectjson.com, 7 Oct 2026
- Conversion and export
- It converts JSON to YAML, CSV, plain text, formatted JSON or minified JSON, and lets users copy or download results. · perfectjson.com, 7 Oct 2026
- Data handling
- Parsing, validation, formatting, diffing and conversion run locally in the browser; edited JSON is not uploaded, and documents and preferences are stored in browser local storage. · perfectjson.com, 7 Oct 2026
- Editing and comparison
- It offers tree or table editing, raw text editing with live highlighting, and a side-by-side JSON diff viewer. · perfectjson.com, 7 Oct 2026
- Formatting and validation
- It formats or minifies JSON and validates against RFC 8259, RFC 7159, RFC 4627 and ECMA-404 with line- and column-specific errors. · perfectjson.com, 7 Oct 2026
- Intended users
- The maker describes it as built for developers who work with JSON, including people handling API payloads, access tokens and configuration files. · perfectjson.com, 7 Oct 2026
- Large numbers
- Its lossless parser preserves large numbers and 64-bit IDs above 9007199254740991 through formatting and editing. · perfectjson.com, 7 Oct 2026
- Privacy and ads
- The site says it uses Google Analytics and Google AdSense, but neither receives the contents of edited JSON; it also says it does not sell personal information or require an account. · perfectjson.com, 7 Oct 2026
- Service terms
- The tool is provided free of charge as is, without warranties, and the maker says it does not guarantee uninterrupted or error-free operation. · perfectjson.com, 7 Oct 2026
- Support
- The site provides separate email contacts for feedback, bugs and feature requests, and for security and privacy questions. · perfectjson.com, 7 Oct 2026
- What it does
- PerfectJSON is a free browser-based JSON formatter, validator and editor. · perfectjson.com, 7 Oct 2026
Where PerfectJSON stands on Freedom251
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