Senior Full-Stack Engineer - Web & Mobile (Scala/React)

FlexTrade; City Of London; On-site; GBP 70,000 - 105,000; Full time

Job summary

FlexTrade UK Ltd. is seeking an experienced full-stack developer to join the FlexONE team. You will work on Scala/Play backend and React/AG-Grid frontend, contributing from an MVP to a full-featured web and mobile companion app.

Based in London with our UI-focused team, you will own design, migrations to React Native, testing, and collaboration with desktop teams to ensure feature parity. Strong communication and ownership are essential to thrive in our fintech environment.

Qualifications

• Deep full stack expertise and production web app experience.
• Significant experience in React and modern TypeScript.
• Willingness to own backend (Java/Scala preferred).
• Experience building or maintaining cross‑platform mobile apps.

Responsibilities

• Design & Build: deliver robust features across Scala/Play backend and React/AG‑Grid frontend.
• Mobile Migration: plan migration from CodenameOne to a JS framework (likely React Native).
• Quality & Reliability: champion testing, observability, and performance.
• Team Growth: mentor engineers, assist with hiring and onboarding as the team scales.
• Collaboration: ensure feature parity with the Desktop app team.
• Backend: Scala, Play Framework, REST/JSON and gRPC.
• Frontend: React, TypeScript, AG-Grid.
• Mobile: migrate to React Native or similar JS cross‑platform framework.

Skills

Deep full stack expertise

React

TypeScript

Java/Scala experience

Mobile capability

Communication

Tools

Scala

Play Framework

REST/JSON

gRPC

CodenameOne

React Native

Job description

FlexTrade UK Ltd. is seeking an experienced full-stack developer to join the FlexONE team. You will work on Scala/Play backend and React/AG-Grid frontend, contributing from an MVP to a full-featured web and mobile companion app.

Based in London with our UI-focused team, you will own design, migrations to React Native, testing, and collaboration with desktop teams to ensure feature parity. Strong communication and ownership are essential to thrive in our fintech environment.