Yodobashi Automated Checkout Bot

Build a production-ready browser automation tool for the Yodobashi online store that completes the entire checkout flow through a clean, fully documented API. The core objective is to reach the order-confirmation page—reliably and at speed—so downstream systems can act on the result in real time.

Key workflow
• Accept an item URL or product-code via my API, log in through a rotating proxy pool with one of many stored accounts, add the item to cart, apply any available coupons, and finish payment.
• On success—or failure—immediately post a JSON payload to a specified Discord webhook so I can monitor every attempt.
• Everything must run headless; Playwright or Puppeteer preferred for speed, but I’m open to other Chromium-based solutions if you can prove lower latency.

Must-have features
• Multi-account login automation routed through proxies
• Automated purchase and payment confirmation
• Discord webhook reporting (success / fail, order ID, used account)
• Full API surface (start job, job status, cancel, logs) with token authentication
• Optimised execution time; benchmark your solution and share metrics

Acceptance criteria
1. Completing checkout on a test SKU under real-world load in ≤ 10 seconds average.
2. Handling at least 50 parallel checkouts without CAPTCHA blocks or proxy leaks.
3. API and codebase delivered with README, environment variables template, and sample cURL calls.
4. Error handling that categorises issues (out of stock, payment decline, proxy timeout, etc.) in webhook responses.

When you reply, focus on relevant experience building high-speed e-commerce bots, dealing with anti-bot measures, and integrating webhooks or REST APIs. Links or brief descriptions of similar projects are enough—I’ll follow up for deeper details after review.