Kepler JSON - Pro Viewer & CORS Tool

Fast in-page JSON viewer with 60 FPS virtual scroll, lossless 64-bit BigInt, local CORS unblocker & AI prompt reducer.

Kepler JSON is a crafted, high-performance in-page JSON viewer and zero-overhead local API debugging companion for modern developers. Designed with an indie clean aesthetic, Kepler JSON renders massive API responses instantly without browser tab freezing, protects 64-bit Snowflake IDs from precision truncation, and unlocks local CORS restrictions using Chrome's native Declarative Net Request engine with 0% background CPU consumption. KEY CAPABILITIES: ⚡ 60 FPS Windowed Virtual Scrolling Renders 50,000+ items smoothly by mounting only visible DOM nodes (~35 elements) in the viewport. Say goodbye to tab freezing on multi-megabyte payloads. 🛡️ Lossless 64-Bit Snowflake ID Protection Pre-scans raw numbers with lossless BigInt preservation before standard JSON.parse can truncate trailing digits. ◫ Bidirectional Split Workspace Directly paste, edit, format, or unescape raw JSON on the left while enjoying a live interactive preview on the right. Features real-time bidirectional synchronized scrolling and instant syntax validation. 🌐 Declarative CORS Unblocking & Header Injection Enables origin reflection and credential support with zero daemon CPU usage. Temporarily unblock local development APIs with auto-expire timers (15m, 1h, or tab close). ✨ AI Token Reducer (Prompt Ready) Compress repetitive JSON arrays into minimal representative samples, saving up to 98% context tokens before feeding data into ChatGPT, Claude, or DeepSeek. 🔒 100% Local-Only Privacy Guarantee Zero remote servers, zero telemetry, and zero tracking. Offline share codes are compressed entirely on your device using LZ algorithms.