Every developer does it at least once a week: you get an unformatted 2MB payload from an internal endpoint or a complex regex string from a colleague, and you throw it into an online web formatter or tester. The problem? Most top search results for "JSON formatter" or "JWT debugger" are laden with heavy ad trackers, telemetry pixels, and in several cases, quietly transmit the pasted text back to an external server. If that payload contains authorization headers, customer PII, API secrets, or internal database IDs, you have just unknowingly leaked confidential data. I got tired of worrying about this, so I built OmniTools Pro — a suite of 16 developer utilities that runs 100% inside your browser with zero backend data transmission. How it works (and why the architecture matters) Zero Server Footprint for Processing: All operations—JSON parsing, YAML conversions, JWT decoding, UUID generation, Diff comparisons, and SHA/MD5 hashing—execute inside local Web Workers and standard Web APIs (crypto.subtle, JSON.parse). If you open your browser DevTools Network tab while using the tool, you will see zero outgoing POST requests. Offline-First PWA: The entire site is cached via a lightweight Service Worker. Once loaded once, you can turn off your Wi-Fi and format or diff code completely offline. Sub-second Load Times: Zero heavy frameworks, zero third-party tracking scripts. Pure vanilla HTML, modular JS, and clean CSS running on Global Edge CDN. Live Demo & Feedback You can test it out live here: https://omnitools-pro.surge.sh I built this primarily to solve my own workflow friction, but I hope it saves other developers time and eliminates unnecessary privacy risks. If you run into edge cases or want additional offline utilities added, let me know in the comments!