X-FLOW is a mobile game development company established in 2018. We gained recognition after the release of Happy Color, the most popular digital coloring book and one of the most successful ad-driven mobile apps in the world. We take pride in our diverse and talented team and partners, spread across the UK, Cyprus, the Netherlands, and other regions worldwide.
We are currently looking for a Senior Fullstack Engineer for our flagship project, Happy Color.
Key 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.
Requirements:
- 4+ years of experience with PHP, strong knowledge of Laravel (DI, queues, profiling, REST, modularity).
- 4+ years of experience with TypeScript, strong knowledge of React/Redux Toolkit, routing, build processes, and bundle optimization.
- Databases: PostgreSQL/MySQL, Redis; experience with schema design, indexes, and transactions.
- Message Queues/Buses: Kafka — experience with event-driven integrations.
- Security: OAuth2, JWT.
- Understanding of DDD, SOLID, 12-Factor App methodology, and observability (Prometheus/Grafana, OpenTelemetry).
Nice to have:
- Experience with Golang development.
- Development experience with Ant Design (Antd) 5+.
- Experience with or understanding of GitLab CI, feature flags, migrations, and blue-green/rolling deployment strategies.
- Testing tools: Jest, Playwright; for PHP — PHPUnit/Codeception; integration/e2e testing experience.
Technology Stack (Core):
- Backend: PHP (Laravel), REST, PostgreSQL/MySQL, Redis, Kafka, Clickhouse.
- Frontend: TypeScript, React, Redux Toolkit.
- DevOps: GitLab CI, Docker.
- Observability: Prometheus, Grafana, OpenTelemetry, Sentry.
What We Offer:
- Competitive salary and benefits package.
- Opportunity to work with a talented and passionate team in a creative and dynamic environment.
- Flexible working hours and remote/office work options.
- Career growth and professional development opportunities.
- A fun and inclusive company culture that celebrates diversity and creativity.
Join us and let’s create great product together!
When you apply for this role, we process your personal data in accordance with our Candidate Privacy Notice (https://xflowgames.com/candidate-privacy-notice).
Skills Required
- 4+ years of experience with PHP and strong knowledge of Laravel (DI, queues, profiling, REST, modularity).
- 4+ years of experience with TypeScript and strong knowledge of React and Redux Toolkit, routing, build processes, and bundle optimization.
- Experience designing and developing RESTful APIs.
- Experience with PostgreSQL or MySQL and Redis; schema design, indexing, and transactions.
- Experience with message queues/event buses, specifically Kafka.
- Knowledge of security protocols: OAuth2 and JWT.
- Understanding of DDD, SOLID principles, and 12-Factor App methodology.
- Experience with observability and reliability tooling: Prometheus, Grafana, OpenTelemetry (logs, metrics, traces, alerts).
- Experience in performance optimization, profiling, and latency reduction.
- Experience contributing to quality assurance: writing unit/integration/e2e tests, performing code reviews, and automating checks.
What We Do
Game dev company founded in 2018, creators of Happy Color® – the world’s most popular colouring app.
