Senior Backend Engineer, Gaming Platform

The French Sourcer; Paris; Hybrid; EUR 90,000 - 130,000; Full time

Benefits offered by this job

Health insurance

Profit-sharing

Incentive schemes

Job summary

The French Sourcer is hiring a senior backend engineer in Paris to design and build scalable Node.js microservices for a real-time gaming platform. You will own services from development to production, focusing on high availability, low latency, and robust data modeling with PostgreSQL/MySQL.

A strong DevOps mindset and experience with containers and CI/CD are essential. You will work in a hybrid setup in Paris, collaborating with frontend, data, security, and infrastructure teams to deliver

Qualifications

• 5+ years of backend engineering on high-traffic platforms (10K+ req/sec)
• Strong production experience with load balancing, high availability, caching, databases
• Expertise in event-driven distributed architectures with Redis/Kafka
• Relational DB skills (MySQL/PostgreSQL) and strong data modeling
• DevOps mindset with containers, CI/CD, and monitoring tools
• Master's degree with a French scientific preparatory class background is required
• Bonus: JavaScript/Node.js production experience and online gaming know-how

Responsibilities

• Design and build Node.js microservices for a gaming platform handling tens of thousands of requests per second
• Develop a scalable authentication, rate limiting, routing, and pub/sub gateway
• Create a high-uptime player registration service for peak sign-ups
• Add new game types and operations to the core engine with stability safeguards
• Design APIs and relational schemas with attention to performance and locking
• Establish testing strategies from unit to load tests and enforce code quality
• Own services in production: deployment, monitoring, tuning, and cross-team collaboration

Skills

Backend engineering

Distributed systems

Performance optimization

DevOps mindset

English communication

Education

Master's degree with French scientific preparatory class

Tools

Node.js

Redis

Kafka

PostgreSQL/MySQL

Docker/Kubernetes

CI/CD tooling

Job description

Paris, France · Permanent · Hybrid

Keep a real-time gaming platform fast and correct when tens of thousands of messages per second hit it at peak, and every lost or duplicated message lands in front of a player with real money on the table.

What you'd actually work on

• Designing and building Node.js microservices for a gaming platform that serves more than 10,000 requests per second, with high availability as a baseline requirement
• Building a communication gateway that handles authentication, rate limiting, routing, and pub/sub messaging at tens of thousands of messages per second
• Building a player registration service that can absorb peaks of around 1,000 sign-ups per second when a big event or campaign brings everyone to the platform at once
• Adding new game types and special operations to the core game engine, so the product team can launch new formats without putting stability at risk
• Designing APIs and relational data models for transactional flows, with close attention to query performance, transactions, and locks
• Setting up a serious testing strategy, from unit and functional tests to load tests that replay production-like traffic, and raising the code quality bar through thorough code reviews
• Owning your services in production: deployment on managed cloud infrastructure, monitoring, performance tuning, and documentation, working closely with the front-end, data, infrastructure, security, and project teams

Where it gets technically interesting

• An event-driven, distributed architecture where game actions and transactions move between services in real time, so ordering, retries, and idempotency stop being theory the moment a message gets delivered twice
• Redis and Kafka at the center of the platform, used for pub/sub, streams, in-memory data structures, and pipelines that have to stay fast under heavy and very uneven load
• A relational data layer (PostgreSQL or MySQL) behind transactional flows, where your locking and transaction design directly decides both correctness and latency
• A proprietary transactional game engine that supports personalized game sessions and built-in anti-fraud mechanisms, which means every new feature has to fit inside strict rules on fairness and data integrity
• Traffic that is anything but flat: evening peaks, major sports events, and promotions put load balancing, caching, and scaling choices to the test on a regular basis
• A regulated industry with always-on expectations, where downtime is visible to hundreds of thousands of players right away, so failure isolation and graceful degradation are part of every design discussion

What we're looking for

• 5+ years of backend engineering experience, including significant time building services on a high-traffic platform (10K+ requests per second)
• Solid production experience with load balancing, high availability, scaling, caching, databases, and storage
• Strong command of event-driven distributed architectures, and deep knowledge of Redis or Kafka (data structures, pub/sub, streams, pipelines)
• Strong relational database skills with MySQL or PostgreSQL: data modeling, query optimization, transactions, and locks
• A DevOps mindset, with hands-on use of containers, CI/CD pipelines, and monitoring tools
• A Master's degree with a French scientific preparatory class background (Maths Sup/Spé), which is a firm requirement for this role
• Bonus: production experience with JavaScript and Node.js, since the existing microservices run on it, and a background in online gaming, sports betting, or another platform with sharp traffic peaks

The company

An established online gaming and sports betting operator headquartered in Paris, with several hundred thousand active players, a strong position in France, and a growing presence in other European markets. Around 500 people, with a product built on in-house technology that handles massive real-time data flows. This is a newly created role in a backend team of four engineers and a lead developer, who you'd report to directly. It's a hands-on individual contributor role with no management, with long-term growth possible and a proper onboarding inside the tech team. Company health insurance, plus profit-sharing and incentive schemes (participation and intéressement).

Languages: French (native or bilingual), English (professional)