Price Scout

Never overpay again. Track prices across online retailers.

Quick Navigation: Features | Quick Start | Usage Examples | CLI Reference | Contributing

What is Price Scout?

Price Scout is a self-hosted price tracker with local data storage. Track product prices across online retailers with all data stored locally (no cloud, no accounts) in a fast DuckDB database with built-in analytics.

Perfect for: Weekly grocery tracking, product comparison, finding deals, and price history analysis.

Key Features

Local Analytics - DuckDB Web UI for price trends and history visualization Local Data Storage - All data stored locally, no accounts, no cloud services Auto-Detection - Automatically detects retailer from URL Product Groups - Compare same product across multiple stores Basket Comparison - Compare total costs across multiple product groups Price Tracking - Historical data with automated change detection Configurable - YAML-based provider configs, easily extensible Docker Ready - One-command setup with virtual display for headless rendering Works with major retailers - Supermarkets, electronics, and more

Quick Start

Docker (Recommended)

The easiest way to use Price Scout with full features:

# 1. Pull and run the container
docker run -d \
  --name price-scout \
  -p 4213:4214 \
  -v price-scout-data:/app/data \
  bulletinmybeard/price-scout:latest

# 2. Scout your first product
docker exec -it price-scout price-scout track --url "PRODUCT_URL"

# 3. Access the web interface (optional)
# Open http://localhost:4213 in your browser

That's it! You're now ready to scout and monitor prices.

Example Output:

✓ Tracked: Example Product Name (500g)
  Price: €9.99
  Provider: store-a

Data saved to database.

Upgrading from a previous version?

price-scout --version

# Check migration status
price-scout db migrate status

# Automation-friendly check (exit 0=ok, 1=pending, 2=error)
price-scout db migrate check

# Apply pending migrations (backup first!)
cp ~/.price-scout/database.duckdb ~/.price-scout/database.duckdb.backup
price-scout db migrate apply

pip (Alternative)

For automation, CI/CD, or lightweight scripting:

# 1. Install with pipx (recommended)
pipx install price-scout

# 2. Install browser support
playwright install firefox

# 3. Scout your first product
price-scout track --url "PRODUCT_URL"

When to Use Docker vs pip

Recommendation: Use Docker for full features and better compatibility.

# Create local directories
mkdir -p data config provider_configs

# Download example configuration (optional)
curl -o config/config.yaml https://raw.githubusercontent.com/bulletinmybeard/price-scout/master/config.example.yaml

# Run with custom mounts
docker run -d \
  --name price-scout \
  -p 4213:4214 \
  -v "$(pwd)/data:/app/data" \
  -v "$(pwd)/config/config.yaml:/app/config.yaml" \
  -v "$(pwd)/provider_configs:/app/provider_configs" \
  bulletinmybeard/price-scout:latest

Usage Examples

Track Your Weekly Groceries

Use case: Track your regular grocery items and see which store offers the best price.

# Track items across stores
price-scout track --url "RETAILER_A_MILK_URL" --group "Weekly Groceries"
price-scout track --url "RETAILER_B_BREAD_URL" --group "Weekly Groceries"
price-scout track --url "RETAILER_C_COFFEE_URL" --group "Weekly Groceries"

# Or track multiple URLs at once
price-scout track \
  --url "RETAILER_A_MILK_URL" \
  --url "RETAILER_B_MILK_URL" \
  --url "RETAILER_C_MILK_URL" \
  --group "Weekly Groceries"

# Compare prices in the group
price-scout groups compare "Weekly Groceries"

# Check price history
price-scout history "PRODUCT_URL"

Example Group Comparison Output:

Weekly Groceries - Price Comparison
┌──────────────┬───────────┬───────┬────────┐
│ Product      │ Store     │ Price │ Change │
├──────────────┼───────────┼───────┼────────┤
│ Milk 1L      │ Store A   │ €1.29 │ ↓ €0.10│
│ Milk 1L      │ Store B   │ €1.39 │ → €0.00│
│ Milk 1L      │ Store C   │ €2.49 │ ↑ €0.20│
└──────────────┴───────────┴───────┴────────┘

Best Deal: Store A (€1.29 for Milk 1L)

Smart shopping: See price trends over weeks. Buy when prices dip, not at peak.

Compare Product Variants

Use case: Which coffee brand offers the best value per gram?

price-scout track --url "RETAILER_A_COFFEE_500G_URL" --group "Coffee"
price-scout track --url "RETAILER_B_COFFEE_250G_URL" --group "Coffee"
price-scout groups compare "Coffee"

Result: See price per unit (€/kg, €/liter) to compare apples-to-apples across different package sizes.

CLI Commands

Common Workflows

# Quick price check (without saving to database)
price-scout track --url "URL" --check

# Track and add to group in one command
price-scout track --url "URL" --group "Group Name"

# Track from a file (one URL per line, # comments are being ignored)
price-scout track --url-file weekly_groceries_products.txt
price-scout track -F weekly_groceries_products.txt --group "Weekly Groceries"

# Refresh all tracked products (creates new snapshots)
price-scout refresh

URL File Argument: The --url-file option searches for files in:

• Current directory
• Data directory (./data/ local, /app/data/ Docker, ~/.price-scout/data/ global)
• User directory (~/.price-scout/)

Basic Commands

# Track a product
price-scout track --url "URL"
price-scout track --url "URL" --group "Group Name"

# Refresh prices (update all tracked products)
price-scout refresh

Product Groups

# Sync groups from config.yaml to database
price-scout groups sync

# List all groups
price-scout groups list

# Compare prices within a group
price-scout groups compare "Group Name"

# Compare basket costs across multiple groups
price-scout compare groups --name "Coffee" --name "Milk" --name "Bread"

Database Management

# Initialize database
price-scout db init

# Show database info
price-scout db info

# Reset database (caution!)
price-scout db reset

Tips & Tricks

ZSH/Bash Function for Docker Users

If you're using Docker, create a shell function to run Price Scout commands more conveniently:

Setup (add to ~/.zshrc or ~/.bashrc):

# Price Scout wrapper function
scout() {
    if ! docker ps --format '{{.Names}}' | grep -q 'price-scout'; then
        echo "Error: price-scout container is not running"
        return 1
    fi
    docker exec -it price-scout price-scout "$@"
}

Usage:

# Instead of: docker exec -it price-scout price-scout track "URL"
scout track "URL"

# Instead of: docker exec -it price-scout price-scout groups compare "Group"
scout groups compare "Group"

Automated Price Monitoring

Schedule regular price updates with cron:

# Add to crontab (run every day at 8 AM)
0 8 * * * docker exec price-scout price-scout refresh

Handling Multi-Offer Products

Many retailers offer different product options and prices, commonly to find for refurbished items or product editions:

Example for a refurbished product):

• Refurbished "Excellent" condition: €509.99
• Refurbished "Very Good" condition: €495.99
• Refurbished "Good" condition: €491.99

How Price Scout Handles This

Price Scout uses an offer selection strategy to determine which price to track:

• first (default) - Select the first price from multi-offer products
• cheapest - Select the lowest price regardless of its availability
• cheapest_available - Select the lowest price that's in stock

Configuration Example:

extraction:
  json_ld:
    offer_selection_strategy: "first"  # or "cheapest" or "cheapest_available"

Strategy Locking

Once a product is tracked and the first snapshot created, the strategy for this product will be locked to the offer_selection_strategy at the time to prevent inaccurate "price changes" over time.

Example of what strategy locking prevents:

• Day 1: Track with cheapest strategy → €491.99 (Good condition)
• Day 2: Config changed to first → €509.99 (Excellent condition)
• Without locking: Database shows 3.7% "price increase" but nothing actually changed!

To change the strategy for a tracked product:

1. Delete the product (removes snapshots, tracking entry, and any now-empty groups):

   price-scout track --delete --url "PRODUCT_URL"
   

2. Re-track the product URL (new strategy will be locked)

Best Practices

For new products (single offer): No action needed - works automatically

For refurbished with multiple offers:

• Use first strategy (default) for most reliable tracking
• Or use cheapest_available if you want best deals
• Understand you're tracking a price point, not a specific condition

For condition-specific tracking:

• Track each condition as a separate product
• Use different product names (e.g., "PS5 (Refurbished - Good)")

Note: Schema.org Limitations

Unfortunately, Schema.org doesn't have a standard for refurbished condition grades (Excellent/Good/Fair). Most retailers mark all offers as generic "RefurbishedCondition" without specifying the grade in structured data.

The condition grades you see in the UI aren't in the JSON-LD data that Price Scout extracts. This is a limitation of the standardized format, not the tool.

Platform Compatibility

Price Scout works on most operating systems:

Technical Note: Docker provides virtual display support (Xvfb) for maximum compatibility.

Contributing

We welcome contributions! Price Scout is built to be extensible—adding new retailers is straightforward.

Adding a New Retailer

Most retailers can be added with just a YAML configuration file:

# provider_configs/new-retailer.yaml
name: "new_retailer"
country: "XX"
base_url: "https://www.retailer.example"
extraction:
  priority: ["json-ld"]  # Most sites support JSON-LD Schema.org

No Python code required for standard retailers. See provider_configs/ directory for examples.

Development Setup

Using Docker Compose (recommended for development):

# Clone the repository
git clone https://github.com/bulletinmybeard/price-scout.git
cd price-scout

# Copy example configuration
cp config.example.yaml config.yaml

# Start with docker-compose (includes all volume mounts!)
docker compose up -d

# Your code changes are immediately reflected
docker exec -it price-scout price-scout --version

Using Poetry (local development):

# Install Poetry
curl -sSL https://install.python-poetry.org | python3 -

# Install dependencies
poetry install

# Install Firefox support
playwright install firefox

# Run Price Scout
poetry run price-scout --help

Ways to Contribute

• Add new retailers - Create YAML configs for stores you use
• Report bugs - Open GitHub Issues with reproduction steps
• Suggest features - Share your ideas for improvements
• Improve documentation - Help others get started
• Write tests - Increase code coverage (current: 37%)

Architecture

Technical Stack

• Browser Automation: Playwright with Firefox (best compatibility)
• Database: DuckDB (columnar analytics database, 100x faster than SQLite for analytics)
• Extraction: JSON-LD (Schema.org structured data) with PyLD library
• CLI Framework: Click with rich formatting
• Data Validation: Pydantic2 with strict type checking
• Docker: Multi-arch support (AMD64 + ARM64) with Xvfb for virtual display

Key Design Decisions

Why DuckDB?

• Optimized for analytics queries (price trends, comparisons)
• Columnar storage = fast aggregations
• Exports to Parquet for zero-copy reads
• Built-in Web UI for data exploration

Why JSON-LD Extraction?

• Standardized format (Schema.org)
• Better compatibility across retailers
• Self-documenting data structure

Why Docker-First?

• Consistent environment across platforms
• Includes Xvfb for headless browser rendering
• DuckDB Web UI included out-of-the-box
• No dependency management hassles

Acknowledgments

Price Scout uses these excellent open-source projects:

• Playwright - Browser automation
• DuckDB - Analytics database
• Click - CLI framework
• Pydantic - Data validation
• PyLD - JSON-LD processing
• Chalkbox - GUI framework

License

MIT License - see LICENSE file for details.

Summary: Free for personal and commercial use. Attribution appreciated but not required.