Looking for a developer to build a Gold price calculator and lead capture page

I am launching a new gold-buying brand and I need a talented developer to help me build a sleek, highly trustworthy standalone landing page. The heart of this website will be an interactive gold price calculator. I want my customers to be able to come to the page, type in how many grams of gold they have, select their gold's karat (10k, 14k, 18k, 22k, or 24k) from a dropdown menu, and instantly see the cash offer I am making them. How the math needs to work:The calculator needs to connect to a live gold market feed (like GoldAPI.io) so it always uses today's current gold price. Since gold market prices are listed in ounces, the code will need to convert that price into grams. The final price shown to the customer should automatically calculate to exactly 80% of the live gold melt value. The Lead Capture feature:Once the customer sees their price, I want a section to pop up that says something like, "Happy with this price? Lock it in before the market changes!" There should be a clean box where they can type in their phone number and a big button that says "Lock in this Price." When they click it, I want their phone number and their gold calculation details sent directly to me (either via email or text message) so I can reach out to them and finalize the deal. What I'm looking for in a freelancer: -You know how to build clean, modern, mobile-friendly web pages. -You have experience working with live APIs (fetching live data streams). -You can help me set up the lead form so I get notifications when people submit their numbers. -You communicate clearly and don't mind explaining things in plain English! If this sounds like a project you’d love to work on, please apply and show me a couple of examples of calculators or interactive forms you’ve built before. Let me know what platform or code you think would be easiest for us to use! i will be giving you the business name and everything else. Here's a website i am inspired by i have attached screenshots below as well: https://thealloymarket.com/calculators/gold/scrap-gold-calculator/