The Role
Design and build backend microservices in Go and frontend features in TypeScript/React. Integrate external services, optimize performance and scalability, design databases and migrations, implement CI/CD and containerized deployments, ensure test coverage and observability, and contribute to architecture and RFCs.
Summary Generated by Built In
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 (Go/TypeScript) for our flagship project, Happy Color.
Key Responsibilities:
- Design and develop microservices in Go (REST/gRPC), public and internal APIs.
- Develop frontend using TypeScript (React) with a focus on performance and Developer Experience (DX).
- Integrate with external services, develop contracts.
- Optimize performance, profiling, reduce latency, and scale systems.
- Design database schemas, perform migrations, indexing, and query optimization.
- Implement and maintain CI/CD, cloud infrastructure (AWS) with Docker/Kubernetes.
- Ensure quality: writing tests (unit/integration/e2e), code reviews, automation of checks.
- Ensure observability and reliability: logging, metrics, alerting, tracing.
- Participate in architectural design, RFCs/ADRs.
Requirements:
- 3+ years of commercial development experience, including 3+ years with Golang and 3+ years with TypeScript.
- Proficient in Go: context handling, concurrency (goroutines/channels), profiling (pprof), gRPC/REST, generics, modularity.
- Strong frontend skills with TypeScript: React, state management (Redux Toolkit), routing, bundle formation, and optimization.
- Databases: PostgreSQL/MySQL, Redis; design, indexing, transactions.
- Queues/Buses: Kafka/NATS — experience in designing event-driven integrations.
- CI/CD: GitLab CI, feature flags, migrations, blue‑green/rolling deployments.
- Testing: Jest, Playwright; for Go — testing/testify, integration/e2e.
- Security: OAuth2, JWT.
- Understanding of DDD principles, SOLID, 12-factor methodology, observability (Prometheus/Grafana, OpenTelemetry).
- Russian - С1/higher, English - B1.
Nice to have:
- Data architecture: CQRS/Event Sourcing, idempotency, deduplication.
- Experience building BFFs, WebSockets.
- Feature flags, experiments/A-B testing, product metrics.
Technology Stack (Primary):
- Backend: Go, gRPC/REST, PostgreSQL, Redis, Kafka.
- Frontend: TypeScript, React, Redux Toolkit, Playwright.
- DevOps: GitLab CI, Docker, nice to have: Kubernetes, AWS, Helm.
- Observability: Prometheus, Grafana, Loki, 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
- 3+ years commercial development experience, including 3+ years with Golang and 3+ years with TypeScript.
- Proficient in Go: context handling, concurrency (goroutines/channels), profiling (pprof), gRPC/REST, generics, modularity.
- Strong frontend skills with TypeScript: React, state management (Redux Toolkit), routing, bundle formation and optimization.
- Databases: PostgreSQL/MySQL and Redis; schema design, indexing, transactions.
- Experience with queues/buses: Kafka and/or NATS and designing event-driven integrations.
- Implement and maintain CI/CD (GitLab CI), feature flags, migrations, blue-green/rolling deployments.
- Testing: Jest and Playwright for frontend; Go testing and Testify for backend; integration and e2e tests.
- Security: OAuth2 and JWT.
- Observability and reliability: Prometheus/Grafana, OpenTelemetry (logging, metrics, tracing).
- Docker and container-based deployment experience.
- Experience with profiling and performance optimization (pprof), reducing latency and scaling systems.
- Understanding of DDD principles, SOLID, 12-factor methodology.
- Languages: Russian - C1 or higher; English - B1.
- Data architecture: CQRS/Event Sourcing, idempotency, deduplication.
- Experience building BFFs and WebSockets.
- Experience with feature flags, A/B testing, and product metrics.
- Kubernetes, AWS, Helm experience.
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The Company
What We Do
Game dev company founded in 2018, creators of Happy Color® – the world’s most popular colouring app.
