Senior Full-Stack Engineer: React.js + Python (FinTech)

OANDA; Kraków; Hybrid; PLN 260,000 - 420,000; Full time

Job summary

OANDA is seeking a Senior Full Stack Engineer to shape the architecture of onboarding flows using React.js and Python (FastAPI). You will own features end-to-end, integrate third-party services, and collaborate with teams globally.

The role emphasizes autonomy, modern tooling including AI assistants, and strong English communication in a hybrid setup in Kraków, Zabłocie. You’ll contribute to robust, scalable cloud-based solutions for fintech onboarding.

Qualifications

• Extensive commercial experience as a Full Stack Developer with React.js and Python (FastAPI).
• Experience with system design, clean architecture, and cloud environments.
• Proven API integrations with third-party services (identity, payments, e-sign).
• Strong testing skills with PyTest, Cypress, Playwright and CI/CD pipelines.
• Excellent English communication (C1) for cross‑functional collaboration.
• High autonomy, ownership, and mentoring abilities.
• Knowledge of Domain-Driven Design (DDD) and Infrastructure as Code (Terraform).
• Experience with modern developer tooling, including AI assistants.

Responsibilities

• Drive the architecture, design, build, and maintain onboarding forms and registration workflows using React.js and Python (FastAPI).
• Oversee third-party vendor API integrations (APIs/SDKs) and collaborate with external providers and internal teams.
• Independently own features and technical initiatives end-to-end — from design to production deployment.
• Ensure clear communication in English across cross-functional teams and stakeholders.
• Write clean, testable code adhering to SOLID and Clean Code, with strong reviews.
• Champion modern tooling (AI assistants, Claude Code) to streamline development and automation.
• Lead team technical discussions, mentor engineers, and drive system-architecture improvements.

Skills

Full stack development

React.js

Python (FastAPI)

System design

Google Cloud Platform

API integrations

Automated testing

CI/CD

English (C1)

Mentoring

DDD

IaC (Terraform)

AI tooling

Tools

PyTest

Cypress

Playwright

Terraform

Claude Code

Job description

OANDA is seeking a Senior Full Stack Engineer to shape the architecture of onboarding flows using React.js and Python (FastAPI). You will own features end-to-end, integrate third-party services, and collaborate with teams globally.

The role emphasizes autonomy, modern tooling including AI assistants, and strong English communication in a hybrid setup in Kraków, Zabłocie. You’ll contribute to robust, scalable cloud-based solutions for fintech onboarding.