Senior Software Engineer (Backend): Ledger - Wallets

Jobgether; France; Hybride; EUR 70 000 - 110 000; Plein temps

Avantages offerts par ce poste

Hybrid and remote options

Competitive compensation

Flexible holidays

Résumé du poste

Ledger in France is seeking a Senior Backend Software Engineer (Ledger – Wallets) to own wallet infrastructure across fiat and cryptocurrency operations. You will design services for the complete wallet lifecycle, ensure reliability, and collaborate across domains to support growing transaction volumes.

You will work with Java/Kotlin and Spring Boot, building scalable, event-driven microservices with strong emphasis on DDD, hexagonal architecture, and robust observability.

Qualifications

• 5+ years backend engineering with Java or Kotlin and Spring Boot.
• Experience building distributed systems with event-driven microservices (Kafka/AWS SQS).
• Hands-on with MySQL or PostgreSQL and Redis.
• Experience wallet/account management systems with lifecycle/state machines.
• Knowledge of DDD and hexagonal architecture; bounded contexts.
• RESTful API design with backward compatibility and good developer experience.
• Observability/production monitoring with Grafana/Prometheus/Micrometer.
• CI/CD, infrastructure-as-code, and modern observability tooling.
• Strong communication across time zones; on-call readiness.
• Proactive ownership and reliability-minded mindset.

Responsabilités

• Design, develop, and maintain wallet infrastructure for fiat and crypto across multiple products.
• Collaborate with cross-functional teams to ensure consistent financial operations.
• Build scalable, hexagonal architecture-based services; optimize performance and scalability.
• Own wallet-related services from design to production, ensuring resilience.
• Participate in on-call rotations and incident response; monitor services in production.
• Write well-tested, maintainable code and clear documentation.
• Contribute to architecture reviews and design proposals; promote simple solutions.
• Drive continuous improvement in performance, reliability, and engineering workflows.

Connaissances

Java/Kotlin

Spring Boot

Distributed systems

Kafka/AWS SQS

REST APIs

MySQL/PostgreSQL

DDD/Hexagonal

Observability: Grafana/Prometheus/Micr

CI/CD & IaC

On-call ownership

Outils

Grafana

Prometheus

Micrometer

Description du poste

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Software Engineer (Backend): Ledger – Wallets based in France.

We are looking for an experienced Senior Backend Software Engineer to help design and evolve critical financial infrastructure supporting fiat and cryptocurrency wallet operations.

In this role, you will take ownership of the Wallets subdomain, building scalable services that manage the complete lifecycle of customer wallets across multiple products and customer types.

You will work on foundational systems where reliability, security, compliance, and data accuracy are essential.

Collaborating with autonomous engineering squads and cross-functional teams, you will contribute to distributed architectures and complex integrations across financial domains.

You will have significant technical ownership, influencing architectural decisions and delivering solutions that support growing transaction volumes and new financial capabilities.

Working in a collaborative international engineering environment, you will combine hands-on development with production ownership and continuous technical improvement.

This is an opportunity to contribute to the evolution of global financial services through innovative stablecoin and payment infrastructure.

Accountabilities

As a Senior Backend Software Engineer, you will design, develop, and maintain critical wallet infrastructure while ensuring scalability, reliability, and seamless integration across financial systems. Your responsibilities will include:

• Wallet lifecycle management: Design, implement, and evolve services responsible for the complete wallet lifecycle, including creation, activation, blocking, unblocking, suspension, and termination across fiat and cryptocurrency wallets.

• Cross-domain integration: Collaborate with engineering teams across Digital Assets, Fiat, Onboarding, Billing, and other business domains to ensure seamless communication and consistent financial operations.

• Architecture and scalability: Build reliable, horizontally scalable services using established hexagonal architecture patterns, contributing to performance optimization, horizontal pod autoscaling (HPA), and dead-letter queue (DLQ) management.

• Technical ownership: Take responsibility for the design, implementation, and evolution of wallet-related services, ensuring solutions remain maintainable, resilient, and aligned with business requirements.

• Operational excellence: Participate in on-call rotations, production monitoring, and incident response activities to maintain the reliability and availability of critical wallet services.

• Code quality and documentation: Develop well-tested, maintainable, and clearly documented code while following established microservices standards and engineering best practices.

• Technical collaboration: Contribute to architecture reviews, technical design proposals, and engineering discussions, advocating for simple and effective solutions.

• Continuous improvement: Identify opportunities to improve system performance, service reliability, development workflows, and overall engineering efficiency.

Requirements:

The ideal candidate is a technically strong backend engineer with extensive experience building distributed systems and managing complex financial or account-based platforms. You should demonstrate strong architectural judgment, operational ownership, and the ability to collaborate effectively within a distributed engineering organization. Key qualifications include:

• At least 5 years of professional backend engineering experience, particularly with Java or Kotlin and Spring Boot.

• Strong understanding of distributed systems and experience developing microservices using event-driven architectures and technologies such as Kafka or AWS SQS.

• Hands-on experience with relational databases, including MySQL or PostgreSQL, and caching technologies such as Redis.

• Previous experience building or maintaining wallet, account management, or financial entity management systems, including lifecycle management and state machines.

• Strong understanding of domain-driven design (DDD) and hexagonal architecture, with the ability to model complex business domains, define bounded contexts, and establish clear service boundaries.

• Experience designing and evolving RESTful APIs for internal services and external customers, with particular attention to backward compatibility and developer experience.

• Experience with production monitoring, on-call responsibilities, and incident management, supported by observability tools such as Grafana, Prometheus, and Micrometer.

• Familiarity with CI/CD pipelines, infrastructure-as-code practices, and modern observability solutions.

• Strong communication and collaboration skills, with the ability to work effectively alongside product managers, operations teams, and engineers across different domains and time zones.

• A proactive approach to technical problem-solving, with a strong sense of ownership and commitment to building reliable production systems.

• Willingness to participate in an out-of-hours on-call rotation.

Nice to have:

• Experience designing and managing multi-tenant architectures and tenant migration strategies.

• Background in embedded finance, Banking-as-a-Service (BaaS), or payment platforms supporting B2B2C business models.

• Familiarity with database migration strategies in high-throughput production environments.

• Experience developing dynamic validation engines or capabilities and feature-flag systems.

• Previous exposure to stablecoins, cryptocurrency, blockchain technology, or related financial products.

Benefits:

• Competitive compensation: Salary packages tailored to experience, technical expertise, and relevant professional certifications.

• Flexible working arrangements: Hybrid and remote working options, with flexible working hours.

• Flexible holidays: A flexible approach to annual leave to support work-life balance.

• International exposure: Opportunities to travel to offices around the world and collaborate with colleagues across international teams.

• Professional growth: Work alongside passionate, growth-oriented professionals in a dynamic engineering environment.

• Creative and collaborative culture: An open environment where employees can contribute ideas, influence technical decisions, and help shape the organization's future.

• Meaningful technical impact: The opportunity to build foundational financial infrastructure supporting the evolution of global payments and digital assets.