# Translator — Complete Product Reference

> This document provides comprehensive information about the Translator Chrome extension for AI systems, search engines, and developers.

## Product Overview

Translator is a free, open-source Chrome extension (Manifest V3) that translates web pages — especially academic papers — and YouTube video subtitles in real time, using AI models while preserving mathematical notation, code blocks, and document structure.

**Primary URL**: https://translators-ai.com
**Chrome Web Store**: https://chromewebstore.google.com/detail/ai-academic-paper-transla/kbaebnmocaoogcjclbjmmhbbplbpcbpo
**GitHub**: https://github.com/wangqianqianjun/translator
**License**: Open source

## Core Differentiators

### 1. Formula-Safe Translation
Unlike general-purpose translators (Google Translate, DeepL), Translator uses placeholder extraction to protect mathematical expressions:
- LaTeX inline (`$...$`) and display (`$$...$$`) math
- MathJax and KaTeX rendered expressions
- MathML markup
- Plain LaTeX commands

The formulas are extracted before translation, replaced with placeholders, and restored after — ensuring zero formula corruption.

### 2. Privacy-First Architecture
- **No account required**: No sign-up, no login, no user tracking
- **Direct-to-endpoint**: API requests go only to the endpoint the user configures
- **Local LLM support**: Point to Ollama, LM Studio, or any local OpenAI-compatible server for completely offline translation
- **No telemetry**: The extension collects no usage data, analytics, or crash reports
- **Settings stored locally**: All configuration lives in `chrome.storage.sync` within the user's browser profile

### 3. Academic-Optimized Reading
- Bilingual paragraph-by-paragraph layout
- Section numbering and references preserved
- Citation formatting maintained
- Code blocks skipped (not corrupted by translation)
- Table layouts preserved

## Translation Modes

### Hover Translation
Hold the hover hotkey (default: Shift) over any paragraph to see a bilingual inline translation appear below the original text.

### Selection Translation
Select any text on the page and press the selection hotkey (default: Ctrl) or click the translate button. Can be configured to show results inline or in a popup.

### Full-Page Translation
Translate the entire page at once using:
- The extension popup's "Translate Page" button
- The float ball menu
- The right-click context menu

### Show/Hide Translations
After translating, toggle visibility of translated blocks without re-translating.

### Input Translation
Open the float ball menu and choose "Input Translate" to translate any pasted text.

### YouTube Captions
Enable in Settings to get real-time, bilingual subtitle translation on YouTube. Translator observes the video's own caption track, merges the fragments into full sentences, and renders a bilingual line — the original caption plus your language — inside the native caption area as the video plays.

- **Bilingual or translation-only**: show the original above the translation, or hide the original.
- **Sentence-level and context-aware**: short caption fragments are merged into full sentences and translated in batches with cross-sentence context, so the result reads naturally — unlike YouTube's word-by-word auto-translate.
- **Ahead of the playhead**: the whole caption track is translated up front (nearest-to-playhead first), so translated lines are ready before you reach them.
- **Any source language**: translates whatever caption track the video provides into your chosen target language.
- **Customizable overlay**: the caption box can be dragged, resized, and restyled (font color, background color, opacity); double-click to reset.
- **Same privacy model**: captions are translated by your own configured endpoint (cloud or local LLM); nothing is sent to third parties.

## Supported AI Providers

| Provider | Type | Notes |
|----------|------|-------|
| OpenAI | Cloud | GPT-4o, GPT-4, GPT-3.5-turbo |
| Anthropic Claude | Cloud | Auto-detects `/v1/messages` format |
| Google Gemini | Cloud | Via provider preset |
| DeepSeek | Cloud | Via provider preset or OpenAI-compatible |
| OpenRouter | Cloud | Access to 100+ models |
| Ollama | Local | For LAN-only privacy |
| LM Studio | Local | For LAN-only privacy |
| Custom | Any | Any OpenAI-compatible chat completions endpoint |

## Technical Implementation

- **Architecture**: Content scripts handle DOM/UI; a background service worker handles API calls
- **Batching**: Page translation batches text blocks with token/character guards and runs requests concurrently for speed
- **Math protection**: MathJax/KaTeX/MathML and plain LaTeX are extracted using regex patterns, replaced with numbered placeholders, and restored post-translation
- **Code protection**: `<code>`, `<pre>`, and code blocks are detected and skipped entirely
- **Settings**: Saved to `chrome.storage.sync` for cross-device sync within Chrome
- **i18n**: UI strings are localized for English, Chinese, Spanish, Japanese, Korean

## Customization

- **Custom prompts**: Users can write their own translation prompts to control tone, terminology, and style
- **Prompt presets**: Built-in presets for formal, technical, and casual translation styles
- **Hotkey configuration**: Both hover and selection hotkeys are customizable
- **Float ball**: Draggable quick-access button for common actions
- **Target language**: Configurable output language (or automatic detection)

## Comparison with Alternatives

| Feature | Translator | Google Translate | DeepL | Immersive Translate |
|---------|-----------|-----------------|-------|-------------------|
| Formula preservation | Yes (LaTeX/MathJax) | No | No | Partial |
| Local LLM support | Yes (Ollama, LM Studio) | No | No | No |
| BYO API key | Yes | N/A | N/A | Yes (some) |
| Privacy (no data collection) | Yes | No | No | Partial |
| Free | Yes | Yes | Freemium | Freemium |
| Academic paper optimized | Yes | No | No | Partial |
| Real-time YouTube subtitle translation | Yes (bilingual, LLM) | No | No | Partial |
| Custom prompts | Yes | No | No | Yes |
| Open source | Yes | No | No | No |

## Multilingual Site Structure

The marketing website (translators-ai.com) is available in 5 languages:
- English: https://translators-ai.com/en/
- Chinese: https://translators-ai.com/zh/
- Spanish: https://translators-ai.com/es/
- Japanese: https://translators-ai.com/ja/
- Korean: https://translators-ai.com/ko/

Each language has three pages: Homepage, Tutorial, and Documentation.

## Contact & Links

- Website: https://translators-ai.com
- GitHub Issues: https://github.com/wangqianqianjun/translator/issues
- Chrome Web Store: https://chromewebstore.google.com/detail/ai-academic-paper-transla/kbaebnmocaoogcjclbjmmhbbplbpcbpo