WhatDiff

A minimal webpage change-monitor. Run it on a schedule (cron) and it compares each configured page against its last-known state, reporting a line-by-line diff whenever something changes.

Use it to watch a product page, a news article, a blog post, a price, a "back in stock" label — anything on the web.

WIP: this is a small work-in-progress script.

Configure

Create config.json with one entry per page you want to watch:

[
  {
    "url": "https://example.com",
    "selector": {
      "type": "id",
      "value": "idofelement",
      "count": 0
    }
  }
]

• url — the page to monitor.
• selector.type / selector.value — which element to track (e.g. an element id).
• selector.count — which match to use when the selector returns several (0-based).

Run

pip install requests beautifulsoup4
python main.py

The first run records the current state into a data/ folder; subsequent runs compare against it and print a unified diff of what changed. Schedule it with cron to monitor continuously, e.g.:

*/30 * * * * cd /path/to/whatdiff && python3 main.py