Senior Fullstack Engineer — Remote & React/Laravel

X-FLOW; Warszawa; Hybrid; PLN 180,000 - 280,000; Full time

Job summary

X-FLOW is seeking a Senior Fullstack Engineer to join our flagship project, Happy Color. You will design backend APIs in PHP/Laravel and build frontend interfaces with TypeScript/React.

You will optimize performance, define API contracts, and contribute to testing, CI, and observability. Flexible hours and remote/office options enable a creative, dynamic work environment.

Collaborate with a diverse global team and grow your skills while delivering high-quality products loved by millions.

Qualifications

• :

Responsibilities

• Design and develop RESTful APIs using PHP/Laravel.
• Build frontend applications using TypeScript/React with a focus on performance and Developer Experience (DX).
• Integrate with external services; define and maintain API contracts.
• Optimize performance, perform profiling, and reduce latency.
• Design database schemas, handle migrations, indexing, and query optimization.
• Contribute to quality assurance: write tests (unit/integration/e2e), conduct code reviews, and automate checks.
• Ensure observability and reliability: implement logs, metrics, alerts, and traces.
• Participate in designing architectural solutions.

Skills

PHP

Laravel

TypeScript

React

Redux Toolkit

REST API

PostgreSQL

MySQL

Redis

Kafka

OAuth2/JWT

DDD/SOLID

Tools

GitLab CI

Jest

Playwright

Job description

X-FLOW is seeking a Senior Fullstack Engineer to join our flagship project, Happy Color. You will design backend APIs in PHP/Laravel and build frontend interfaces with TypeScript/React.

You will optimize performance, define API contracts, and contribute to testing, CI, and observability. Flexible hours and remote/office options enable a creative, dynamic work environment.

Collaborate with a diverse global team and grow your skills while delivering high-quality products loved by millions.