About the Role We're looking for a

Senior Backend Developer

who thrives in a deeply hand-on environment and enjoys being close to the code on a daily basis. This role is heavily focused on building, optimising, and scaling backend services in a high-load system where performance and reliability are critical.

You'll be working on complex, real-time challenges at the core of our platform - improving latency, ensuring high availability, and making systems more efficient at scale. This is not a coordination-heavy role; it's for someone who enjoys writing production code, solving tough engineering problems, and seeing the direct impact of their work.

If you're product-driven, take ownership, and prefer a "build first, improve fast" approach while working on systems where every millisecond matters - this role will feel like home.

Key Responsibilities

Work as part of a cross-functional team owning a core product within the platform

Design, build, and deliver new backend features end-to-end in a distributed environment

Write high-quality, production-level code daily, contributing directly to a high-load, scalable system

Take ownership of services handling financial transactions at scale, with a strong focus on reliability and accuracy

Proactively suggest and implement improvements in architecture, processes, and development practices

Participate in code and architectural reviews to maintain high engineering standards

Solve complex business and technical challenges with pragmatic, efficient solutions

Participating in

on-call rotations

within the squad to ensure the reliability and availability of our systems

Play an active role in ongoing tech transformation initiatives across the platform

Collaborate closely with engineers, product, and other stakeholders to deliver impactful solutions used by millions globally

Requirements

Solid experience with Node.js/TypeScript is ideal,



but we also welcome experts in other OOP languages such as Java, Python, C++, C#, or Go

Strong understanding of asynchronous programming techniques

Deep production experience with Kafka: confident reasoning about consumer-group rebalances and their impact on in-flight processing, offset-commit strategies under retries and duplicate delivery, and the limits of "exactly-once" semantics

Experience designing idempotent, retry-safe handlers for at-least-once pipelines: transactional outbox, idempotency keys, and deduplication

Experience building services with gRPC or similar RPC frameworks

Strong knowledge of relational databases such as MySQL or PostgreSQL, plus production experience with at least one NoSQL technology at scale, such as DynamoDB, MongoDB, or Redis

Hands-on experience running services on Kubernetes and AWS/GCP: deployment, autoscaling, resource limits, and production debugging

Production operations experience: on-call ownership of a high-load system, including incident response, impact assessment, root-cause analysis, and post-incident improvements

Nice to Have

Experience with ClickHouse or other columnar/analytical databases

Experience with multi-region / failover architectures: data replication, regional isolation, and graceful degradation

Practical use of AI coding agents such as Cursor or Claude Code as part of daily development: effective prompting, reviewing, and validating AI-generated code

Understanding of application security and industry best practices

Gambling domain experience

What We Offer

Competitive Salary

Quarterly Bonuses

Unlimited Paid Time Off

Unlimited Paid Sick Leave

Remote & Adaptable Working

Private Medical Insurance

Financial Support for Life Events

Professional Development Budget

International Exposure

Regular Company Events

*Benefits may vary depending on location and contractual agreement

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📌 Senior Backend Engineer (Core Team) (Madrid)
🏢 Playson
📍 Madrid