Cortance

Senior Frontend / Mobile Engineer

Bohdan B

Information

Available hours \ week
40 h/w
Seniority level
Senior
Years of experience
8 yrs.
Location
Ukraine
Nationality
Ukraine
Timezone
(GMT+02:00) Kyiv

Languages

English
Advanced (C1)

About

Bohdan focuses on building real-time web and mobile user experiences, with about 8 years in production delivery as a Senior Frontend / Mobile Engineer. He works primarily with JavaScript, React.js, TypeScript, React Native, Angular, Node.js, iOS and Android, balancing product UI polish with maintainable architecture. Typical work includes migrating legacy codebases, shaping front-end structure, and shipping features end to end from discovery to release. His scope often involves live communication and data-heavy screens: WebRTC calls with quality monitoring, WebSockets event flows, and resilient client behavior under poor networks. He also delivers integrations around REST API, GraphQL, Redux-Saga, and testing with Jest. Industries covered include healthcare, HealthTech, hospitality operations, betting-style consumer apps, analytics dashboards, etc.

Main technologies

Additional skills

Experience

MediFlow — Telemedicine Platform for 24/7 Doctor Consultations

Senior Frontend Engineer

About the Project

Telemedicine platform enabling 24/7 patient-doctor video consultations, with real-time streaming as a business-critical, uptime-sensitive component of patient care.

  • HealthTech

Responsibilities

- Owned client-side WebRTC implementation end-to-end: RTCPeerConnection lifecycle, SDP/ICE negotiation, H.264/VP8 codec configuration; - Implemented adaptive bitrate streaming and graceful degradation for stable video consultations under variable network conditions; - Built real-time session quality monitoring to detect and respond to degraded connections during live calls; - Utilized Supabase Realtime for instant event propagation (call invitations, session status changes, chat messages); - Worked in a production system where connection stability directly affected patient care outcomes.

Skills & technologies

App for Hospitality Staff Management

Team Lead / Front-End Developer

About the Project

App helping hospitality businesses manage room readiness and staff task assignment across basic and Pro subscription tiers.

  • Management

Responsibilities

- Led a React Native/Expo mobile and web app from FE architecture through TestFlight and App Store release, supervising junior developers; - Completely restructured and refactored the codebase from JavaScript to TypeScript, taking over an inherited, partially-built application and stabilizing it for production; - Implemented In-App Purchases (IAP) with StoreKit for Pro subscription tiers, including sandbox testing and App Store review compliance; - Utilized Supabase for user authentication and real-time task status synchronization; - Implemented global state management (Recoil) and built a new taskboard feature from scratch; - Built a new sign-up flow with integration options for various third-party PMS platforms.

Skills & technologies

Online Betting Platform

Front-End Developer

About the Project

Web and mobile betting app offering live odds, real-time scores, and in-app challenges across multiple sports.

  • E-commerce
  • Entertainment

Responsibilities

- Inherited an existing web application from a prior team, conducted structured code review to map implemented features against business requirements, and ported it into native mobile apps for iOS and Android; - Built live-odds and real-time score features shared across web and mobile clients; - Maintained and extended existing functionality across both platforms in parallel.

Skills & technologies

Veterinary Project — AI Pet Health Mobile App

Front-End Developer

About the Project

Mobile application that leverages AI to support proactive pet health management, letting users log symptoms and receive instant, AI-generated assessments.

  • HealthTech

Responsibilities

- Built the React Native/Expo mobile client for symptom logging and health tracking; - Implemented instant AI-generated assessments and tailored care recommendations based on logged data; - Integrated Supabase for real-time data synchronization and user authentication; - Integrated the mobile client with a Node.js/MongoDB backend for continuous data sync.

HealthApp — Doctor's Appointment Platform

Team Lead / Front-End Developer

About the Project

One of the largest doctor-appointment platforms in the market, enabling online appointments and remote consultations at scale.

  • Healthcare

Responsibilities

- Joined as senior developer and grew into leading the front-end team as the platform scaled to hundreds of thousands of patients; - Built the core appointment-booking flow, including consultation entry points and numerous scheduling filters; - Provided technical leadership and mentored front-end engineers as the team grew.

Meal & Delivery Planning Platform — Admin Dashboard

Front-End Developer

About the Project

Administration service for doctors to monitor patient device data (insulin injections, sugar levels) and adjust treatment plans accordingly.

  • HealthTech

Responsibilities

- Built the admin dashboard for doctors to view and manage continuously collected patient device data; - Implemented real-time aggregation and statistical display of large-volume health data on the admin page; - Handled large, constantly-updating data volumes as a core technical challenge of the platform.

Health & Activity Analytics Dashboard

Front-End Developer

About the Project

Smartwatch-connected web dashboard providing insight and coaching into user activity and sleep patterns.

  • Healthcare

Responsibilities

- Built a dashboard with charts and widgets tracking walked distance, sleep, and calories burned; - Implemented per-day, per-month, and per-year views of user activity statistics; - Delivered the full UI/UX and markup for the analytics dashboard.