Senior Front-End Engineer – Interactive Financial Simulation Widgets (TypeScript / JavaScript)

About Genieum Genieum is an Australian fintech developing a global B2B trade-credit platform for Australia, the United Kingdom and the United States. We have already completed the commercial design, financial modelling and mathematical logic for a suite of interactive financial simulation widgets. We are now seeking an experienced front-end engineer to convert those completed specifications into production-quality interactive widgets. This is not a greenfield software design project. The mathematical models, calculation logic and developer specifications have already been completed. Your role is to engineer them into production-ready browser-based widgets. IMPORTANT Please do NOT apply if you are primarily: a WordPress developer; a Laravel or PHP CRUD application developer; a React web application developer with no experience building financial calculators; a UI designer without strong JavaScript engineering skills; an agency intending to subcontract the work; a developer who has not previously built interactive financial calculators or simulation tools. We are specifically seeking someone who has previously built interactive browser-based financial calculators or simulation widgets. The Project Initially the project consists of approximately six browser-based interactive widgets, including: Supplier Financial Benefit Simulator Buyer Working Capital Simulator Partner Income Simulator Single Invoice Transaction Simulator Assumption Manager Scenario / Sensitivity Analysis The widgets will be used: on our public website; within landing pages; within Moodle LMS; within educational resources; as standalone marketing assets. These widgets are not intended to become part of our core application platform. Existing Materials The successful developer will receive: comprehensive business specification; calculation logic; working HTML proof-of-concept; plain-English functional guide; developer workbook; validation and acceptance tests. The mathematical model author (located in India) will remain available throughout development to answer implementation questions and verify calculations. Technical Requirements The widgets should be built using: Required HTML5 CSS3 TypeScript (preferred) or modern JavaScript (ES6+) Chart.js Backend Very limited PHP endpoints only where required for: configuration; assumptions; analytics events. The calculations themselves should execute entirely within the browser. Design Objectives The widgets should: load quickly; work on desktop, tablet and mobile; be embeddable into different websites; be reusable across multiple pages; separate calculation logic from presentation; use configurable assumptions rather than hard-coded values; support Google Analytics events; support Microsoft Clarity; support future CRM integration. Phase 1 Deliverable Initially this engagement is for: review the supplied documentation; recommend the final technical architecture; identify any implementation questions; provide a fixed-price quotation and development plan. Developers progressing successfully through Phase 1 will be invited to complete Phase 2. Phase 2 Deliverable Build all widgets. Testing against supplied acceptance tests. Deployment-ready source code. Implementation documentation. Required Experience You should have demonstrable experience building: financial calculators; investment simulators; mortgage calculators; lending calculators; insurance calculators; pricing simulators; interactive business tools. Please include links where possible.