Translate PDF documents using LLMs. Supports OpenAI, Claude, Gemini, and any OpenAI-compatible API.

Preserves original PDF layout — backgrounds, images, shapes, and logos stay intact. Only text is replaced with translations.

npm install -g pdf-translate

Or run directly without installing:

npx pdf-translate input.pdf -l zh-TW

# Translate to Traditional Chinese (default)
pdf-translate input.pdf -l zh-TW

# Translate to Japanese using Claude
pdf-translate input.pdf -l ja --provider claude

# Translate using Gemini
pdf-translate input.pdf -l ko --provider gemini --model gemini-2.5-flash

# Use a local model (Ollama, vLLM, etc.)
pdf-translate input.pdf -l zh-TW --base-url http://localhost:11434/v1 --model qwen3

# Translate specific pages
pdf-translate input.pdf -l zh-TW --pages 0-4

# Specify output path
pdf-translate input.pdf -l de --output translated.pdf

# List available models from a provider
pdf-translate models --provider claude

1. Extract — pdf_oxide reads text spans with coordinates, fonts, and colors
2. Translate — LLM translates each page independently (page-by-page to prevent context bleeding)
3. Replace — Content stream manipulation: strip original text operators, inject translated text with CJK font embedding
4. Output — Modified PDF with original layout preserved

┌──────────────────────────────────────────────┐
│  Node.js CLI (TypeScript)                    │
│  - Command-line interface                    │
│  - LLM API calls (openai SDK)               │
│  - Per-page translation with batching        │
├──────────────────────────────────────────────┤
│  Rust Core (pdf_oxide + lopdf)               │
│  - PDF text extraction with coordinates      │
│  - Content stream manipulation               │
│  - CJK font embedding (Noto Sans CJK TC)    │
│  - Mixed CJK/Latin font rendering            │
└──────────────────────────────────────────────┘

• Multi-span lines: Text split across multiple PDF spans on the same line may show gaps after translation. Paragraph grouping is planned for v0.2.0.
• No text reflow: Translated text longer than the original may overflow its bounding box.
• CJK font size: The embedded Noto Sans CJK TC font adds ~16MB to the output file. Font subsetting is planned.
• First CJK run: Downloads the CJK font (~16MB) on first use. Cached after that.

• Rust (stable)
• Node.js >= 22
• pnpm >= 10

# Build Rust core
cargo build --release --manifest-path crates/core/Cargo.toml

# Install Node.js dependencies
pnpm install

# Build CLI
pnpm --filter pdf-translate build

# Run in development
pnpm --filter pdf-translate dev -- input.pdf -l zh-TW

# Run tests
cargo test --manifest-path crates/core/Cargo.toml --lib

MIT