Context & Mission

We are looking for a curious and rigorous Junior Backend Engineer to help design, build, and operate our microservices powering the Lefty platform. You’ll work primarily with Java (21+) and modern JVM tooling, build gRPC/Protobuf APIs consumed by our apps, and contribute to data-heavy services using Elasticsearch, ScyllaDB and MariaDB. You’ll collaborate with senior engineers, learn best practices, and take ownership of well-scoped features from design to production.

You’ll join an agile, ambitious team that values technical excellence, observability, and reliability. You’ll contribute to services that ingest and process large-scale social data, including features leveraging open-source AI models to enrich and classify content.

About the position

• Design and implement services in Java: Build well-structured, maintainable microservices with clean boundaries and clear domain models.

• Define fast, typed APIs: Ship and evolve gRPC services with Protobuf schemas. Keep contracts stable and backward compatible.

• Search and storage at scale: Model and query data effectively with Elasticsearch for search and ScyllaDB for high-throughput, low-latency workloads.

• Quality and reliability: Write unit and integration tests, participate in code reviews, and contribute to resilient, observable systems with logging, metrics, and tracing.

• Operate what you build: Help monitor production, debug incidents with teammates, and propose pragmatic improvements.

• Collaborate cross-functionally: Work closely with Product, Frontend, and Data to clarify requirements and deliver business value incrementally.

• Build and test with Bazel: Use Bazel as our build system for fast, reproducible, and scalable builds and CI. It’s a Google-grade toolchain that helps us keep builds hermetic and reliable.

We are looking for an engineer with 0–2 years of professional experience in backend development.

Technical skills

• Java fundamentals: Solid understanding of modern Java features, concurrency basics, and the JVM ecosystem.

• API development: Experience building backend APIs.

• Microservices basics: Understanding of service boundaries, configuration, and inter-service communication.

• Git: Daily use of Git.

Soft skills & mindset

• Ownership / autonomy: You follow through on your tasks, ask for help early, and care about the impact on users.

• Learning mindset: You’re eager to deepen your backend fundamentals and learn from reviews and pairing.

• Pragmatism: You balance iteration speed with system stability and maintainability.

• Team spirit: We’re a kind, supportive team that values a positive, energetic atmosphere. We help each other grow, celebrate wins together, and keep a good mood even when the problems are hard.

Nice to have

• Exposure to gRPC/Protobuf.

• Good knowledge of SQL and Hibernate ORM.

• Datastores: Familiarity with at least one of the following and readiness to learn both: Elasticsearch, MariaDB and Cassandra/ScyllaDB.

• Testing: Comfortable writing unit tests and basic integration tests.

• CI: Experience with CI pipelines.

• Knowledge of streaming or batch data processing patterns.

• Exposure to AI/Open-source models integration in backend services.

• HR call (10min)

• Online coding test (~30min)

• Interview with CTO and a member of the tech team (~1,5 hours)

We welcome international candidates already holding a valid French work visa. Please note that we are not able to provide visa sponsorship at this stage.