Senior Backend Engineer — Blockchain Wallet Services — Hybrid, Paris, France

Overview

Develop the services that connect consumer wallets and institutional custody platforms with blockchain networks. The work covers account information and the complete transaction lifecycle, requiring careful treatment of differences between chains. Production ownership is central: the engineer who designs an integration also helps observe its behavior, diagnose failures and improve the reliability of the services around it.

Requirements

• Bring at least five years in backend engineering with ownership of distributed systems in production.
• Have hands-on integration experience with at least two of account-based, UTXO and privacy-preserving blockchain models.
• Understand event-driven systems and observability, show interest in Scala and functional programming, and be comfortable contributing TypeScript.
• Write clear English design and incident documentation and review AI-generated code critically.

Responsibilities

• Build services for account creation, transaction history, transaction construction, broadcast and lifecycle tracking.
• Lead blockchain integrations from architectural decisions through release, coordinating clear service boundaries with wallet and coin-integration teams.
• Maintain service-level measures, distributed tracing and useful operational evidence, and resolve incidents across service boundaries during the support rotation.
• Review designs and code, improve test coverage and technical documentation, and guide AI coding tools with explicit specifications and verification.
• Share practical knowledge with other engineers and contribute to consistent backend engineering standards.

Conditions

• This is full-time hybrid work in Paris, including production incident rotation.

Tech stack

• Scala
• TypeScript
• PostgreSQL
• RabbitMQ
• NATS
• Datadog