About SafeJSON
Our mission
SafeJSON exists because developer tools should not require trusting strangers with your data. Every time you paste an API response, a JWT token, or a configuration file into an online tool, you are making a security decision - whether you realize it or not.
We believe sensitive developer tools should make their processing boundary verifiable. SafeJSON core workflows run in the browser and are designed so pasted content is not intentionally uploaded. This is verifiable: open DevTools -> Network tab while using SafeJSON and check that no request contains your pasted content.
Why SafeJSON was built
In November 2025, security researchers at watchTowr revealed that jsonformatter.org and codebeautify.org - two of the most popular online JSON tools - had been leaking user data for over five years. An unprotected feature exposed 80,000+ code snippets containing AWS access keys, GitHub personal access tokens, database passwords, and banking PII. Attackers were actively harvesting the data within 48 hours of the discovery.
Around the same time, the most popular JSON Formatter Chrome extension - with over 2 million users - was sold to a new owner. The extension was closed-sourced and injected with tracking scripts, checkout popups, and a hardcoded API key for harvesting user location data.
SafeJSON was built as a direct response: keep core JSON workflows browser-local and make the pasted-content boundary easy to verify.
How it works
SafeJSON is a static web application built with Next.js and Tailwind CSS, deployed on Vercel. Core JSON formatting, validation, diff comparison, JWT decoding, JSONPath evaluation, and schema validation run in browser JavaScript for pasted input. Normal site delivery, analytics, billing, and license activation may still use network requests.
The entire codebase is open source under the MIT license and available on GitHub. You can audit every line of code to verify these claims independently.
Built by an independent developer
SafeJSON is developed and maintained by a solo developer who builds verifiable browser-local tools. The project is self-funded and independent - no venture capital, no external investors, no corporate parent company.
Being independent means we answer only to our users. There is no pressure to monetize through data collection, advertising, or tracking. The business model is straightforward: core tools are free forever, and Pro features are available through a paid subscription while preserving the no pasted-content upload boundary for core tool inputs.
Contact
For questions, feedback, or bug reports, open an issue on GitHub. For security-sensitive matters, refer to the repository's security policy.