---
title: Docling Multi-Template Extraction API
emoji: 📄
colorFrom: blue
colorTo: green
sdk: docker
pinned: false
license: apache-2.0
---

# Docling Multi-Template Document Extraction API

🚀 Deploy Docling on Hugging Face Spaces with dynamic template matching for invoice and payment advice extraction.

## Features

- 🔄 **Dynamic Template Discovery**: Automatically detects and loads templates from the `templates/` directory
- 🎯 **Smart Name Matching**: Works with any naming convention (snake_case, kebab-case, PascalCase)
- 🤖 **Auto-Detection**: Automatically identifies document types from content
- 📊 **Structured JSON Output**: Extract invoices, payment advices, and custom documents to JSON
- 🌐 **REST API**: Easy integration with n8n, Make, Zapier, or custom workflows
- 🎨 **Web UI**: Built-in Gradio interface for testing

## Quick Start

### Deploy to Hugging Face Spaces

1. **Create a new Space:**
   - Go to [huggingface.co/spaces](https://huggingface.co/spaces)
   - Click "Create new Space"
   - Name: `docling-api` (or your preferred name)
   - SDK: **Docker**
   - Hardware: **CPU basic (free tier)** - 2 vCPU, 16 GB RAM

2. **Clone and push code:**
```bash
git clone https://huggingface.co/spaces/YOUR-USERNAME/docling-api
cd docling-api

# Copy all files from this project
# (app.py, templates/, requirements.txt, Dockerfile, README.md)

git add .
git commit -m "Initial deployment"
git push
```

3. **Wait for build** (5-10 minutes for first deployment)

4. **Your API is live at:** `https://YOUR-USERNAME-docling-api.hf.space`

## API Endpoints

### Extract Document Data
```http
POST /api/extract
Content-Type: multipart/form-data

Query Parameters:
- template_type: auto | payment_advice | invoice | custom_template
```

**Example with curl:**
```bash
curl -X POST "https://YOUR-SPACE.hf.space/api/extract?template_type=auto" \
  -F "file=@invoice.pdf"
```

**Response:**
```json
{
  "success": true,
  "template_used": "invoice",
  "data": {
    "bill_no": "JRPL14725-26",
    "bill_date": "03-12-2025",
    "total_amount": 16618.0,
    "seller": {
      "name": "Jobuss Resources Pvt Ltd",
      "gst_no": "27AAECJ2353C1ZX"
    },
    "buyer": {
      "name": "Reliance Industries Limited",
      "vendor_code": "3347687"
    }
  },
  "filename": "invoice.pdf"
}
```

### List Available Templates
```http
GET /api/templates
```

### Template Variations
```http
GET /api/templates/variations
```

## Flexible Naming

All these work identically:
```bash
?template_type=payment_advice    # snake_case
?template_type=payment-advice    # kebab-case
?template_type=PaymentAdvice     # PascalCase
?template_type=PAYMENT_ADVICE    # UPPER_CASE
```

## Using with n8n

### Setup HTTP Request Node

1. **Method:** POST
2. **URL:** `https://YOUR-SPACE.hf.space/api/extract`
3. **Query Parameters:**
   - Name: `template_type`
   - Value: `auto` (or specific template name)
4. **Body Content Type:** Multipart-Form-Data
5. **Body Parameters:**
   - Name: `file`
   - Type: `n8n Binary File`
   - Input Data Field Name: `data` (or your binary field)

### Example n8n Workflow

```
[Trigger/File Input] 
    ↓
[HTTP Request - Docling API]
    ↓
[Code Node - Parse Response]
    ↓
[Database/Spreadsheet Output]
```

### Parse Response in Code Node (n8n)

```javascript
// Access the extracted data
const response = $input.item.json;

if (response.success) {
  const data = response.data;
  
  return {
    invoice_number: data.bill_no,
    date: data.bill_date,
    amount: data.total_amount,
    vendor: data.seller?.name,
    all_data: data
  };
}
```

## Adding Custom Templates

Create a new file in `templates/` directory:

### Example: `templates/purchase_order_template.py`

```python
from pydantic import BaseModel, Field
from typing import Optional, List

class POLineItem(BaseModel):
    item_code: Optional[str] = Field(default=None)
    description: Optional[str] = Field(default=None)
    quantity: Optional[float] = Field(default=None)
    unit_price: Optional[float] = Field(default=None)
    total: Optional[float] = Field(default=None)

class Vendor(BaseModel):
    vendor_id: Optional[str] = Field(default=None)
    name: Optional[str] = Field(default=None)
    address: Optional[str] = Field(default=None)

class PurchaseOrder(BaseModel):
    document_type: str = Field(default="purchase_order")
    po_number: Optional[str] = Field(default=None)
    po_date: Optional[str] = Field(default=None)
    delivery_date: Optional[str] = Field(default=None)
    vendor: Optional[Vendor] = Field(default=None)
    subtotal: Optional[float] = Field(default=None)
    tax_amount: Optional[float] = Field(default=None)
    total_amount: Optional[float] = Field(default=None)
    line_items: Optional[List[POLineItem]] = Field(default=[])
```

**That's it!** The template is automatically discovered and available at:
```
?template_type=purchase_order
```

## Template Naming Convention

File must follow this pattern:
- **Filename:** `{template_name}_template.py`
- **Class name:** PascalCase version of template_name (e.g., `PurchaseOrder`)
- **Must inherit from:** `pydantic.BaseModel`

Examples:
- `payment_advice_template.py` → class `PaymentAdvice`
- `invoice_template.py` → class `Invoice`
- `purchase_order_template.py` → class `PurchaseOrder`

## Auto-Detection Keywords

Edit `template_router.py` to add detection rules:

```python
detection_rules = {
    "payment_advice": ["payment advice", "payment document"],
    "invoice": ["tax invoice", "bill no", "invoice date"],
    "purchase_order": ["purchase order", "po number"],
    "your_custom_type": ["your", "keywords", "here"],
}
```

## Web Interface

Access the Gradio UI at: `https://YOUR-SPACE.hf.space/gradio`

- Upload documents
- Select template or use auto-detect
- View extracted JSON instantly

## Supported Document Formats

- PDF documents
- Images (PNG, JPG, JPEG)
- DOCX (requires additional configuration)

## Hardware Requirements

### Free Tier (CPU basic)
- ✅ Standard invoices (1-5 pages)
- ✅ Payment advices
- ✅ Simple documents
- ⚠️ Large PDFs may timeout (30s limit)

### Upgraded Tier (Recommended for production)
- CPU basic upgrade: 4 vCPU, 16 GB RAM
- Faster processing
- Handle larger documents

## Troubleshooting

### Template Not Found Error
```json
{"detail": "Template 'xyz' not found. Available templates: payment_advice, invoice"}
```
**Solution:** Check filename matches `{name}_template.py` pattern

### Timeout Errors
**Solution:** Upgrade to larger hardware tier or reduce document size

### Import Errors
**Solution:** Ensure all dependencies in `requirements.txt` and rebuild Space

## API Rate Limits

Hugging Face Spaces free tier:
- No official rate limit
- Fair usage policy applies
- For production: Consider Hugging Face Pro ($9/month)

## Local Development

```bash
# Clone repository
git clone https://huggingface.co/spaces/YOUR-USERNAME/docling-api
cd docling-api

# Install dependencies
pip install -r requirements.txt

# Run locally
uvicorn app:app --host 0.0.0.0 --port 7860 --reload
```

Access at: `http://localhost:7860`

## Environment Variables

Optional configurations (add in Space settings):

```bash
# Logging level
LOG_LEVEL=INFO

# Max file size (MB)
MAX_FILE_SIZE=50
```

## Security Notes

- ⚠️ Free tier Spaces are public by default
- 🔒 For sensitive documents, use private Spaces (Hugging Face Pro)
- 🔐 Consider adding API key authentication for production

## Contributing

Add new templates or improve detection logic:

1. Fork the Space
2. Add your template in `templates/`
3. Update detection rules in `template_router.py`
4. Test with sample documents
5. Submit pull request

## License

Apache 2.0

## Support

- Documentation: [Docling GitHub](https://github.com/docling-project/docling)
- Issues: Create issue in your Space repository
- Community: Hugging Face Discord

## Credits

Built with:
- [Docling](https://github.com/docling-project/docling) - Document processing
- [FastAPI](https://fastapi.tiangolo.com/) - Web framework
- [Gradio](https://gradio.app/) - Web interface
- [Pydantic](https://docs.pydantic.dev/) - Data validation

---

**Made with ❤️ for the document automation community**