PHP Debit Card Validator

I already have an active API and a working endpoint that return the response codes I need; what’s missing is the actual PHP tool that will hit that endpoint, feed it card data, and clearly tell me whether a given debit card is valid.

Here is what I need built:

• A clean PHP script (or small set of scripts) that accepts card number, expiry, and CVV, calls my provided endpoint, and parses the response so it reads “valid” or “invalid” to the user in real-time.
• The checker will live on its own URL and does not have to hook into my existing marketplace back-end—you will simply see the marketplace so the look and feel can stay consistent.
• Basic error handling for malformed inputs, rate-limit or timeout responses, and any non-200 codes returned by the API.
• A short README that explains required PHP version, any composer packages used, and how to swap in my live API key when I move from sandbox to production.

Acceptance criteria
1. Submitting a known-good test card returns “valid” instantly.
2. Submitting an intentionally bad card returns “invalid” with the proper message.
3. No sensitive details ever log to disk or echo to the browser console.
4. Code installs with a single composer install (or none if you keep it vanilla PHP).

I will share the endpoint URL, the marketplace link for styling reference, and my test API key as soon as we begin.