Privacy Policy

Last updated: February 26, 2026

1. Introduction

Welcome to CHROMANGA. This Privacy Policy explains how we handle information when you use our Chrome Extension. We are committed to transparency about our data practices, which can be summed up simply: we do not collect your personal data.

2. What Data We Collect

2.1 Chrome Extension

CHROMANGA is designed with a privacy-first architecture. The Extension does not collect, transmit, or store any personal information. Specifically:

No user accounts or authentication are required.
No analytics, telemetry, or usage tracking is performed.
No images or manga pages are ever sent to our servers or any third-party server.
No browsing history is recorded or transmitted.
No cookies are set by the Extension.

The only data the Extension stores is saved locally on your device using Chrome’s built-in storage APIs:

User Preferences (via Chrome Storage API): display settings such as color saturation, denoising preferences, image quality, WebGPU toggle, cache size limits, view mode, and your custom site allowlist. These never leave your browser.
Cached Colorized Images (via IndexedDB): temporarily cached results of colorization to avoid re-processing. Cached images are stored as WEBP data with a SHA-256 hash identifier and are automatically evicted using a least-recently-used (LRU) policy or after 24 hours, whichever comes first.

2.2 Website

Our Website is a static informational site built with Next.js. It does not require sign-up, does not collect form data, and does not use analytics services such as Google Analytics, Mixpanel, or Segment.

The only cookie used on the Website is a theme preference cookie (light/dark mode), managed by the next-themes library. This cookie is stored locally in your browser and is never transmitted to us.

3. How Colorization Works (Data Flow)

When you colorize a manga page, the entire process happens locally on your device. Here is the exact data flow:

The Extension’s content script detects manga images on the page you are reading.
The image data is extracted using an HTML Canvas element or fetched via the background service worker (to bypass CORS restrictions). No credentials or cookies are sent with these fetch requests.
A SHA-256 hash of the image is computed to check the local IndexedDB cache.
If not cached, the image is passed to an offscreen document running ONNX Runtime Web (by Microsoft), which performs AI inference using a colorization model bundled with the Extension.
Inference runs on your device’s hardware via WebGPU (preferred) or WebAssembly (WASM) as a fallback. No data is sent to any external server.
The colorized result is returned and displayed in place of the original image. Small results (<5 MB) are cached locally in IndexedDB; larger results can be downloaded to your device.

In summary: Your manga images never leave your browser. All AI processing is performed locally using a model that ships with the Extension. There are zero network calls to CHROMANGA servers during colorization.

4. Chrome Extension Permissions

The Extension requests the following permissions under Chrome’s Manifest V3 framework. Each permission is used solely for the purposes described below:

storage — Saves your preferences (color saturation, denoising settings, site allowlist, etc.) locally via Chrome’s Storage API. No data is synced or transmitted externally.

activeTab — Grants access to the currently active tab so the Extension can detect and replace manga images on the page you are viewing. This permission is scoped only to the tab you interact with.

scripting — Allows dynamic injection of content scripts to detect manga images and render the colorization UI overlay on supported sites.

downloads — Enables downloading large colorized images (>5 MB) directly to your device when they exceed the in-browser cache limit.

offscreen — Creates an offscreen document to run the ONNX Runtime inference engine in an isolated context, separate from visible tabs. This is required for local AI processing.

tabs — Queries open tabs to determine which sites are supported for content script injection and colorization.

Host Permissions (pre-listed manga sites) — At install time, the Extension is granted access only to a curated list of manga reader domains (such as MangaDex, MangaPlus, MangaFire, and others listed in the Extension’s built-in site configuration). These permissions let the content script auto-inject on those sites and allow the background service worker to fetch image data for colorization. Image fetches are always made with credentials: ’omit’, so your cookies, session tokens, and login state are never attached.

Optional Host Permissions (custom sites) — If you want to use CHROMANGA on a site not in the built-in list, you can add it through the Extension’s popup. Chrome will prompt you to approve access to that specific domain before the Extension can operate there. This permission is never requested silently—it requires your explicit consent each time. You can revoke any granted optional permission at any time through Chrome’s extension settings.

5. Third-Party Services

5.1 ONNX Runtime Web (Extension)

The Extension uses ONNX Runtime Web, an open-source inference engine by Microsoft, to run the AI colorization model. The ONNX Runtime library and model files are bundled with the Extension and execute entirely on your device. No data is sent to Microsoft or any other party.

5.2 Google Fonts (Website)

Our Website uses Google Fonts (Inter typeface) served via next/font, which downloads font files at build time. When you visit the Website, your browser may connect to Google’s font servers (fonts.googleapis.com and fonts.gstatic.com). Google’s privacy policy governs any data collected during that connection. We do not receive any data from Google in this process.

6. Data Sharing and Transfers

We do not sell, rent, share, or transfer any user data to third parties. Since we do not collect personal information, there is no data to share. There are no advertising networks, data brokers, or affiliate tracking integrations in CHROMANGA.

7. Data Retention

All data stored by the Extension resides locally on your device:

Preferences: Stored indefinitely until you change them or uninstall the Extension.
Cached images: Automatically purged after 24 hours or when the cache exceeds your configured size limit (LRU eviction). You can also clear the cache manually from the Extension settings.

Uninstalling the Extension removes all locally stored data, including preferences and cached images.

8. Children’s Privacy

CHROMANGA does not knowingly collect any personal information from anyone, including children under the age of 13. Since no personal data is collected at all, there is no specific data processing related to minors.

9. Your Rights

Because we do not collect personal information, most data-subject rights (access, correction, deletion, portability) under regulations like the GDPR, CCPA, and similar frameworks are inherently satisfied. You have full control over the data stored locally on your device:

You can view and modify your preferences at any time through the Extension’s options page.
You can clear the image cache from the Extension settings.
You can uninstall the Extension to remove all associated data.

10. Security

The Extension operates under Chrome’s Manifest V3 security model, which enforces a strict Content Security Policy (CSP) restricting script execution to Extension-bundled files only. Image fetch requests are made with credentials: ’omit’ to prevent cookies or authentication tokens from being sent. Our Website is served with security headers including X-Frame-Options: DENY, X-Content-Type-Options: nosniff, and Referrer-Policy: strict-origin-when-cross-origin.

11. Changes to This Policy

We may update this Privacy Policy from time to time. If we make material changes, we will update the “Last updated” date at the top of this page. We encourage you to review this policy periodically. Your continued use of CHROMANGA after changes constitutes acceptance of the updated policy.

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