What Happened to JSON Formatter (Chrome Extension by Callum Locke)?
The popular 'JSON Formatter' Chrome extension, developed by Callum Locke, gained widespread adoption among developers for its ability to prettify JSON data in the browser. However, in early 2026, the extension controversially transitioned to a closed-source model and began injecting adware and performing geolocation tracking, leading to significant user backlash and warnings across developer communities.
Quick Answer
The 'JSON Formatter' Chrome extension, widely used by developers, recently underwent a significant and controversial change. As of early 2026, it transitioned from an open-source project to a closed-source model and was found to be injecting adware onto checkout pages and performing geolocation tracking. This development, highlighted on platforms like Reddit and Hacker News in March and April 2026, has led many users to uninstall the extension and seek secure, open-source alternatives.
📊Key Facts
📅Complete Timeline11 events
Initial Release and Growth
The JSON Formatter Chrome extension, developed by Callum Locke, was released and began to gain traction among developers for its efficient JSON prettifying capabilities.
JSONView Security Vulnerability
A prominent alternative, JSONView, was temporarily removed from the Chrome Web Store due to a serious security vulnerability, potentially increasing the user base for other formatters like JSON Formatter.
Mentioned as a Top Recommendation
A YouTube video highlighted the JSON Formatter extension (ID: bcjindcccaagfpapjjmafapmmgkkhgoa) as a highly recommended tool for formatting JSON, noting its 2 million users.
Continued Popularity and Features Highlighted
Another video reiterated the extension's usefulness for developers, citing its nearly 2 million users and features like syntax highlighting and theme options.
Online JSON Tool Security Leaks
Research revealed that online JSON formatters like JSONFormatter.org and CodeBeautify had exposed thousands of sensitive credentials due to server-side processing, underscoring the value of client-side extensions.
Update to a Different 'JSON Formatter' by Seiri
A different Chrome extension also named 'JSON Formatter' by developer 'Seiri' was updated to version 1.0.1, indicating the presence of multiple extensions with similar names.
Last Known Update for Callum Locke's Version
The 'JSON Formatter' extension by Callum Locke (ID: bcjindcccaagfpapjjmafapmmgkkhgoa) received an update to version 0.10.0, shortly before the controversy erupted.
Adware and Tracking Discovery Reported
A Reddit post alerted the developer community that the 'JSON-formatter' extension had gone closed source, was injecting adware via 'Give Freely' on checkout pages, and performing geolocation tracking.
Update to Another 'JSON Formatter' by Arnav Kumar
Yet another 'JSON Formatter' extension, developed by Arnav Kumar, was updated to Version 2.1.14 Beta, maintaining its open-source status and offering numerous themes.
Alternatives Highlighted Amidst Concerns
Articles began comparing various JSON Chrome extensions, implicitly and explicitly offering alternatives to the now-controversial 'JSON Formatter' due to its issues.
Hacker News Alert Confirms Adware Injection
A Hacker News post titled 'JSON Formatter Chrome Plugin Now Closed and Injecting Adware' brought widespread attention to the issue, confirming the malicious behavior of the popular extension.
🔍Deep Dive Analysis
The 'JSON Formatter' Chrome extension, primarily associated with developer Callum Locke, rose to prominence as an indispensable tool for web developers and data analysts. Its core functionality involved automatically detecting and prettifying raw JSON data displayed in browser tabs, transforming it into a readable, color-coded, and collapsible tree structure. This feature significantly streamlined debugging and data inspection workflows, leading to its adoption by millions of users, reportedly reaching over 2 million installs by 2025.
Initially lauded for its simplicity, effectiveness, and perceived commitment to user privacy (often stating 'No tracking, no data collection'), the extension provided features like dark mode support, syntax highlighting, code folding, and clickable URLs. Its widespread use made it a default recommendation in many developer circles for handling JSON responses directly within the Chrome browser.
The turning point for the extension occurred in early 2026. Around March, users began reporting suspicious behavior. It was discovered that the extension had gone closed source and was actively injecting adware, specifically through a service called 'Give Freely,' which hijacked checkout pages to solicit donations. Furthermore, the extension was found to be performing geolocation tracking by querying `maxmind.com`, raising significant privacy concerns among its user base.
The consequences of these changes were immediate and severe. Developer communities on platforms like Reddit and Hacker News quickly identified and discussed the malicious behavior, with strong recommendations for users to uninstall the extension. This incident highlighted the inherent risks associated with browser extensions, particularly those that gain broad permissions and then change their operational model or ownership. The developer's email, `reddy.vivaanh@gmail.com`, was also associated with the extension during this period.
As of April 10, 2026, the 'JSON Formatter' extension (ID: `bcjindcccaagfpapjjmafapmmgkkhgoa`) is widely regarded as compromised within the developer community. While it may still be available on the Chrome Web Store, the strong warnings from privacy-conscious users and security analysts have led to a significant exodus of its user base. This event has underscored the importance of vetting browser extensions, favoring open-source alternatives, and being vigilant about permissions and network activity. Many developers have since migrated to other trusted JSON formatting tools and extensions that prioritize client-side processing and transparency.
What If...?
Explore alternate histories. What if JSON Formatter (Chrome Extension by Callum Locke) made different choices?