Backend Engineer (m/f/d)

Qivalis; Oelsnitz; Vor Ort; EUR 70.000 - 110.000; Vollzeit

Zusammenfassung

Qivalis in Europe seeks a Senior Backend Engineer to own secure, compliant backend systems powering a fintech platform with a focus on auditability and security. You will drive Fireblocks crypto custody integration and contribute to a modern Kotlin/Spring Boot backend across Europe.

The role requires strong ownership, collaboration with CTO, Product, QA, and Compliance, and a commitment to scalable, auditable infrastructure in a regulated environment.

Qualifikationen

• 5-8 years of production experience as a Backend or Full-Stack Engineer.
• Strong experience with Kotlin or JVM languages (Java) and Spring Boot.
• Hands-on expertise with event-driven architectures (Kafka or similar).
• Proven experience designing RESTful APIs and integrating third-party systems.
• Solid understanding of OAuth 2.0 / OIDC and identity providers (Zitadel/Keycloak/Auth0).
• Experience in regulated environments (fintech, banking, ISO 27001, PCI-DSS) with auditability.

Aufgaben

• Own the Fireblocks crypto custody integration and maintain it with external partners.
• Design secure, auditable integration layers between backend services and external APIs.
• Develop backend services using Kotlin/Spring Boot for scalable, maintainable solutions.
• Build and operate RESTful APIs and event-driven architectures (Kafka).
• Implement secure authentication/authorization flows using OAuth/OIDC (Zitadel).
• Apply compliance-by-design across backend development for auditability and regulatory alignment.
• Collaborate with QA, Security, and Compliance to ensure high-quality releases.

Kenntnisse

Kotlin

Spring Boot

PostgreSQL

Kafka

REST APIs

OAuth/OIDC

Regulated environment

Ownership mindset

Tools

Kafka

PostgreSQL

Zitadel

Keycloak

Auth0

Jobbeschreibung

About the Role

As a Senior Backend Engineer, you will play a key role in building the secure and compliant backend infrastructure of a fast-growing, Amsterdam-based fintech backed by leading European banks. The company is developing a MiCA-compliant, euro-denominated stablecoin and is progressing towards authorisation by the Dutch Central Bank.

In this role, you will take ownership of critical backend systems that power next-generation digital payment infrastructure across Europe. A central focus will be the internalization and further development of the Fireblocks-based crypto integration, while contributing to a modern Kotlin/Spring Boot backend in a highly regulated environment.

You will work closely with the CTO, Product, QA, and Compliance teams, shaping systems end-to-end - from architecture to implementation - with a strong focus on scalability, auditability, and security.

Your Responsibilities

• Take full ownership of the Fireblocks crypto custody integration, including knowledge transfer from external partners and ongoing development.
• Design and implement secure, auditable integration layers between backend services and external APIs, ensuring full traceability.
• Develop and maintain backend services using Kotlin/Spring Boot, translating product requirements into scalable and maintainable solutions.
• Build and operate RESTful APIs and event-driven architectures (e.g. Kafka), ensuring reliability, fault tolerance, and idempotency.
• Implement secure authentication and authorization flows using OAuth/OIDC-based identity solutions (e.g. Zitadel).
• Apply a compliance-by-design approach across all backend development, ensuring auditability and alignment with regulatory standards.
• Collaborate closely with QA, Security, and Compliance teams to ensure high-quality releases and successful audit outcomes.

Required Qualifications

What You Bring

• 5-8 years of experience as a Backend or Full-Stack Engineer in production environments.
• Strong experience with Kotlin or JVM-based languages (Java), as well as Spring Boot and PostgreSQL.
• Hands-on expertise with event-driven architectures (e.g. Kafka or similar messaging systems).
• Proven experience designing RESTful APIs and integrating third-party systems.
• Solid understanding of OAuth 2.0 / OIDC and identity providers such as Zitadel, Keycloak, or Auth0.
• Experience working in regulated environments (e.g. fintech, banking, ISO 27001, PCI-DSS) with a focus on auditability.
• Strong ownership mindset and ability to communicate technical concepts to non-technical stakeholders.

Core Competencies

• Technical ownership - You take full responsibility for the systems you build and proactively manage risks and dependencies.
• Compliance and security mindset - You embed auditability, traceability, and security into every layer of your work.
• Collaborative engineering - You work closely with cross-functional teams and contribute to a strong engineering culture.
• System thinking - You design scalable, resilient architectures and understand the broader system impact of your work.
• Adaptability - You bring structure and clarity to complex, evolving environments and shifting priorities.