Esther Amoo

Frontend Web Developer with 3+ years of experience building production-grade, HIPAA-compliant healthcare applications and SaaS platforms using React, Next.js, TypeScript, and Tailwind CSS. Track record integrating large-scale REST API service layers, architecting scalable dashboard systems, and shipping accessible, high-performance interfaces deployed on Cloudflare Workers. Skilled at translating complex product and design requirements into clean, type-safe, maintainable code within fast-moving cross-functional teams.

Frontend Developer - WithinLabs - Dallas, TX, USA (Remote)

(2025-04)

Healthcare Technology

• Implemented and integrated 30+ RESTful API service modules against a Rails backend — covering billing, insurance, Stripe subscriptions, coupons/promotions, waitlist management, templates, and user management — each with full CRUD operations, Zod response validation, and TanStack Query cache management, built on a reusable 4-layer pattern (Types → Service → Hook → Page) adopted across 25+ dashboard modules.
• Integrated Stripe billing APIs including subscription migrations with proration behavior control, versioned billing products and plans, and full coupon/promotion code lifecycle management (create, activate, deactivate, validate).
• Built the insurance API layer — usage analytics, payer directory, enrollment tracking, billable-status API log monitoring, stale claims detection, and ERA report attribution — including a CSV export endpoint with client-side file download.
• Designed a parameterized query builder used across all paginated endpoints (insurance logs, payers, enrollments, coupons, waitlist), supporting dynamic filtering, sorting, and shareable URL-based pagination state via nuqs.
• Implemented token-authenticated API calls with automatic refresh queue coalescing and HIPAA-compliant headers on every request, eliminating concurrent refresh race conditions and improving interface responsiveness by 40%.
• Developed a real-time analytics dashboard with timezone-aware KPI filtering, SSR-safe Recharts rendering, and per-section error boundaries — all with zero PHI exposure — alongside 24+ white-labeled Next.js marketing sites built on a shared, WCAG 2.1 AA-compliant component library.
• Wrote unit tests with Vitest/Testing Library and E2E tests with Playwright, and maintained multi-environment CI/CD pipelines (GitHub Actions) deploying to Cloudflare Workers via OpenNext.

Frontend Developer Intern - Intern Pulse - Nigeria

(2024-10 - 2025-03)

SaaS Development

• Designed responsive components for an auction marketplace platform, increasing user engagement by 50%.
• Streamlined REST API integrations, decreasing data latency by 60% and reducing development cycles by 30% through reusable dynamic components.
• Partnered with design teams to align feature functionality with business objectives, ensuring on-time project delivery.

Frontend Developer Intern - Afribreath Ltd - Nigeria

(2024-05 - 2024-10)

E-Commerce

• Improved e-commerce site performance with Tailwind CSS and TypeScript, boosting page load speed by 45%.
• Implemented real-time data rendering via API integrations, improving user experience by 30% and team output by 25% through Git-based version control workflows.

Higher National Diploma - Computer Science - Osun State Polytechnic (2006-06)