Ecommerce Price Watcher

Monitor product URLs, keep price history, detect offers, and output alert-ready JSON.

Quick start

Use scripts/price_watch.py.

# URL mode
python3 skills/ecommerce-price-watcher/scripts/price_watch.py add \
  --url "https://example.com/product" \
  --target-price 399990 \
  --currency CLP

# Item mode (discover URLs from query)
python3 skills/ecommerce-price-watcher/scripts/price_watch.py add-item \
  --query "iPhone 13 128GB Chile" \
  --target-price 349990 \
  --currency CLP \
  --trusted-only \
  --max-results 5

python3 skills/ecommerce-price-watcher/scripts/price_watch.py check --all

Commands

• add: add a single product URL
• add-item: discover product URLs from an item query, then add watches
• list: list watched products
• check --id <id>: check one product now
• check --all: check all products now
• remove --id <id>: delete watcher
• history --id <id>: print full price history

Alert behavior

A check produces alerts when at least one condition matches:

1. price_drop: current price < previous price
2. target_hit: current price <= target price

Alert payload includes:

• product id
• title
• old/new price
• drop percent (when available)
• URL
• timestamp

Item-query mode details

add-item uses a lightweight search discovery flow to find candidate product links.

• --trusted-only restricts discovered URLs to a curated trusted domain list.
• --max-results controls how many links are added.
• Duplicate URLs are skipped safely.

This gives users natural language entry ("track iPhone 13 128GB") instead of forcing direct URLs.

Parsing strategy

Use a layered parser:

1. JSON-LD offers.price
2. Open Graph/meta price fields
3. Generic HTML regex fallback

When multiple prices are found, choose the lowest positive value as the current offer candidate.

Security standards

• Accept only http/https URLs.
• Enforce request timeout.
• Enforce response body size cap.
• Do not execute remote JavaScript.
• Store no API keys/tokens in watcher data.
• Treat all page content as untrusted.
• Return structured JSON for safe downstream automation.

Limits and operational notes

• Some stores block bot-like requests (403). This is expected on certain sites.
• Price extraction is best-effort and may need store-specific adapters over time.
• For production alerting, run check --all on schedule and forward only non-empty alerts.

Suggested scheduled usage

Run every 30–120 minutes via cron, then send each alert to Telegram/WhatsApp/Discord.