Senior Backend Developer

Build the backend services behind a real-time gaming platform processing tens of thousands of messages every second.

Senior Backend Developer - Real-Time Platform

Paris, France · Permanent · On-site

What you'd actually work on

• Designing highly available backend architecture for a real-time transactional platform
• Building and maintaining scalable microservices using server-side JavaScript
• Developing APIs and data models used by the platform's core services
• Contributing to a communication gateway handling authentication, flow control, routing, and asynchronous messaging
• Developing user registration services capable of absorbing significant traffic peaks
• Adding new functionality and mechanics to the platform's core engine
• Improving application performance, scalability, and resource usage
• Designing automated unit, functional, integration, and load tests
• Reviewing code and contributing to shared engineering standards
• Deploying services on managed cloud infrastructure
• Implementing monitoring and investigating production performance
• Maintaining technical and architectural documentation
• Working with frontend, data, infrastructure, security, and project teams

Where it gets technically interesting

• A communication gateway processing tens of thousands of messages per second
• Event-driven services where ordering, retries, duplicate messages, and partial failures must be managed explicitly
• Server-side JavaScript used for concurrent, high-throughput systems beyond standard web applications
• Services that must absorb sudden traffic peaks without affecting availability
• Asynchronous messaging and in-memory data structures supporting real-time application flows
• Relational databases operating under concurrent transactional workloads
• Query optimisation, transaction boundaries, and lock management under contention
• Caching and load-distribution decisions that directly affect performance and consistency
• A modular platform requiring continuous availability and strict protection of user data

What we're looking for

• 5+ years of experience building and operating backend services in production
• Strong experience with server-side JavaScript and Node.js
• Experience developing services that handle high request or message volumes
• Good understanding of high availability, load distribution, scalability, and caching
• Experience designing microservices and event-driven architectures
• Strong knowledge of asynchronous messaging systems and in-memory data structures
• Experience with relational data modelling and complex query optimisation
• Understanding of transactions, concurrency, locking, and data consistency
• Practical experience with automated unit, functional, integration, and load testing
• Knowledge of containers, continuous deployment pipelines, and monitoring tools
• Ability to investigate performance and production issues across multiple technical layers
• A Master's degree or equivalent technical background

The company

A European digital entertainment company operating high-volume online platforms across several markets.

The organisation employs approximately 500 people and serves hundreds of thousands of active users. Its proprietary transactional platform supports real-time activity, personalised user experiences, and fraud prevention while maintaining strict availability and data protection requirements.

Health insurance, profit-sharing, and an employee incentive scheme.

Languages: Native or bilingual French and professional English.