Base64 Auto Decoder

Automatically scan and decode Base64 text on webpages, replace in-place, and provide a one-click copy button.

A lightweight, pure native, and high-precision Chrome extension for automatic webpage Base64 decoding, JWT inspection, and image previewing (Manifest V3). When browsing GitHub, Reddit, developer forums, or API documentation, do you constantly run into obfuscated Base64 strings or JWT tokens that force you to open external converter tabs? Base64 Auto Decoder solves this painlessly—scanning and decoding Base64 strings directly in place as you browse! ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ✨ KEY FEATURES ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 1. 🔍 Automatic In-Place Scanning & Decoding • Millisecond-level auto scanning on page load and SPA mutations (infinite scroll, pagination, new comments). • Replaces encoded Base64 strings with readable plain text inline. • Clean inline 📋 copy button next to decoded text with instant feedback. • Hover over any decoded text to inspect the original Base64 with a smooth, non-flickering popover. 2. 🎯 High-Precision Anti-False-Positive Engine • Strict UTF-8 verification using native TextDecoder. • Intelligently skips standard English words, plain numbers, UUIDs, Git Commit SHA1/SHA256 hashes, and binary gibberish, ensuring zero page layout breakage. 3. ⚡ JWT (JSON Web Token) Smart Inspection (Enhanced in v1.2.1) • Instant In-Page Status Badges: Know if a token is valid before even hovering: - [JWT 🟢] Active (Valid, not yet expired) - [JWT 🔴] Expired - [JWT ⚪] No Expiry (Permanent token without exp claim) • Human-Friendly Countdown: Computes relative duration based on your clock (e.g., "Expires in 25m" or "Expired 2h ago"). • Localized Datetime: Converts raw 10/13-digit Unix timestamps into human-readable local time (e.g., 2026-09-12 23:59:00). • Dual-Action Popover: Structured display of algorithm, subject, and pretty-printed Payload JSON, featuring both "Copy Payload" and "Copy Token" (ready to paste into Postman or curl). 4. 🖼️ Base64 Image Detection & Hover Preview • Identifies data:image/... and raw magic headers (PNG, JPEG, GIF, WEBP). • Displays a green [IMG] badge in the page; hover reveals a crisp thumbnail preview with dimensions. • One-click "Download Image" and "Copy Image URL" buttons included. 5. 🖱️ Context Menus & In-Place Input Replacement • Select any text on any page -> right-click to "Convert to Base64" or "Base64 Decode". • In inputs, textareas, and contenteditable fields: transforms text in-place without leaving the input! • On standard page text: copies result directly to clipboard with a floating toast notification. 6. 🌐 Per-Site Toggle & Domain Blacklist Management • Compact side-by-side iOS control cards automatically sensing current site domain. • Toggle auto-decoding on/off for the current site with instant cross-tab synchronization. • Built-in collapsible Blacklist panel to easily add custom domains or remove existing ones. 7. 📋 Quick Base64 Snippets Manager • Save commonly used contacts, URLs, or phrases with custom tags. • Automatically encodes to standard Base64 and syncs across all your Chrome devices via chrome.storage.sync. 8. 💡 Instant Smart Decoder in Popup • Paste any Base64 or JWT string into the popup input to instantly inspect formatted previews and copy results. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 🔒 PRIVACY & PERFORMANCE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ • 100% Native & Zero Dependencies: Built strictly with Vanilla HTML/CSS/JS without heavy frameworks or build tools. Ultra-compact package size (~39 KB)! • Fully Offline & Private: All scanning, decoding, and calculations occur 100% locally in your browser. Zero tracking, zero telemetry, and zero network calls. • Minimal Permissions: Only requests "storage" (preferences) and "contextMenus" (right-click actions). • Bilingual & Dark Mode: Features instant [ EN / 中 ] header language switcher and full Dark Mode support.