Replace ad-injected, memory-leaking legacy extensions. Unblock local CORS without backend changes, inject custom headers with dynamic macros, view massive JSON with 64-bit Snowflake precision, and compress context tokens by 99% for AI models.
Test our 64-bit Snowflake ID precision guard, windowed virtual scroll, and AI prompt reduction without installing anything.
Kepler JSON combines the utility of 4 separate legacy tools into one cohesive, lightweight, privacy-guaranteed extension.
Bypass cross-origin restrictions on any localhost or staging API without touching backend code. Dynamically reflects request Origin and supports cookies with Access-Control-Allow-Credentials: true.
connect-src blocks on dev sites.
Inject, replace, or strip headers like Bearer tokens and tenancy identifiers with zero reload lag. Includes dynamic macro generators for authentic payloads.
Standard extensions round 64-bit IDs (e.g. 18446744073709551615) causing silent production bugs. Kepler JSON protects BigInt precision while rendering 50,000+ items at steady 60 FPS with windowed virtual scrolling (~40 DOM nodes).
Extract clean JSON schemas into AI prompts with PII sanitization and 99% token reduction. Share environments with teammates using client-side LZ-string tokens without any cloud server.
High-resolution captures of Kepler JSON's 60 FPS virtual scroll, split workspace, zero-overhead CORS unblocking, and developer AI suite.
Client-side PII sanitizer · 1-click production React/Vue UI prompt · Natural language JSON anomaly radar
Zero tab freeze · Mounts only ~35 DOM nodes · Lossless Snowflake IDs
Paste, format, and unescape on the left while enjoying synchronized scrolling
Origin reflection, credentials support, macro injection & auto-expire timers
Compress 100k JSON to ~200 tokens ready for Cursor, ChatGPT, and Claude
Compare Kepler JSON directly against legacy extensions that developers have relied upon for years.
| Evaluation Metric | Kepler JSON (v1.0) | ModHeader | Allow CORS | JSON Formatter |
|---|---|---|---|---|
| Privacy & Tracking | ✅ 100% Local / 0 Telemetry | ❌ Injected Ads / Banned | ⚠️ Closed-Source | ⚠️ Tracking SDKs |
| Idle Background Footprint | ✅ 0% CPU / 0 RAM Leak | ❌ Heavy webRequest hook | ❌ 200MB+ Memory Leak | ⚠️ Content Script overhead |
| 64-bit Snowflake ID Safety | ✅ Lossless BigInt Regex | N/A (Header only) | N/A (CORS only) | ❌ Truncates / Rounds |
| Large JSON Scroll (10k+ rows) | ✅ 60 FPS Virtual (~40 nodes) | N/A | N/A | ❌ Freezes / Crashes Tab |
| AI Context Token Reducer | ✅ 99% Token Saving Prompt | ❌ None | ❌ None | ❌ None |
| Team Sharing Mechanism | ✅ Offline LZ-Token (Zero Cloud) | Requires Cloud Account | ❌ None | ❌ None |
Everything you need to know about Kepler JSON's security, permissions, and architecture.
ModHeader was penalized by Google Chrome Web Store for injecting unauthorized ad and tracking scripts after ownership transfers. Kepler JSON is 100% open-source under the MIT license, has no analytics SDKs, and runs purely on local declarativeNetRequest rules with zero cloud communication.
JavaScript numbers are 64-bit floating-point (IEEE 754), meaning integer precision is lost above 9,007,199,254,740,991 (2^53 - 1). Traditional JSON viewers parse JSON with JSON.parse, permanently destroying large backend IDs. Kepler JSON pre-scans the raw HTTP text stream at document_start and wraps large integers so they display exactly as returned by your server.
Never. Kepler JSON has zero remote servers, databases, or API telemetry. All rules and variables are stored strictly on your local disk in chrome.storage.local. Team profile sharing operates via client-side LZ-string compression copied straight to your clipboard.
Legacy extensions keep a persistent JavaScript background page or webRequest event listener active for every single browser request. Kepler JSON compiles user rules into Chromium's native C++ declarativeNetRequest engine. Once compiled, Chromium handles the network headers directly—Kepler JSON's service worker goes to sleep with 0% CPU footprint.
Free, open-source, and installs in 5 seconds. Join developers who demand 0% background overhead and uncompromised privacy.