Senior Backend Engineer - Api Trading EMEA F - M - D H/F Flowdesk

> International environment (English is the main language)

> 50% of transportation costs & a sustainable mobility agreement

> Swile lunch voucher (€9.25 per day, 60% covered)

> 100% Alan Blue covered for you and your children

> Wellpass contribution to gym membership

> Team events and offsites

Here's what you can expect if you apply

- HR call (30') Get to know Flowdesk and discuss your experience.
- Introduction interview with the Head of Engineering (30')
- Technical Test
- Technical round with the Head Of Engineering (60') & Team Fit (60') onsite
- Wrap Up Interview (45'), Learn about Flowdesk's culture and how we work.
- C-Level Interview (30')

We focus on conversations, not trick questions. These discussions will help you understand how Flowdesk operates and allow you to share your journey and what you're looking for in your next role.

We are committed to an inclusive and accessible recruitment process. If you require any reasonable adjustments or have specific needs to enable you to participate fully in the interview or assessment process (e.g., a sign language interpreter, extra time for a test, or an accessible location), please contact us to discuss how we can support you.

Must Have

- English is mandatory
- 5+ years of backend software engineering experience, ideally in trading, crypto, or high-throughput financial systems.
- Proven track record designing and shipping client-facing APIs used in production.
- Hands-on experience building and operating backend services in Rust.
- Comfortable owning services in production - performance, observability, debugging.
- Direct experience building or maintaining a public API for an exchange or trading firm (or very similar environment).
- Strong knowledge of REST and WebSocket APIs (protocol design, error handling, rate limits, versioning).
- Experience with OpenAPI (specs, code generation, compatibility management).
- FIX protocol knowledge is a big plus.
- Solid experience implementing API authentication (HMAC / key-based auth, signatures, tokens).
- Understanding of common API attack vectors and mitigations (OWASP-style threats, replay attacks, abuse control).
- Comfortable working with TypeScript for SDKs, tooling, or integration layers.
- Able to think from the integrator's perspective - how developers discover, test, and use your APIs.
- Clear, concise communicator in English (written and spoken).
- Able to work closely with trading, product, and other engineering teams, challenge requirements when needed, and converge on practical solutions.

Nice to Have

- Experience in crypto trading, digital asset exchanges, or market making.
- Exposure to matching engines, execution engines, or algorithmic trading systems (designing APIs around them is a strong plus).
- Strong interest or background in security (secure coding practices, threat modeling, cryptographic primitives).
- Contributions to open source around APIs, Rust, or security.

Founded in 2020, Flowdesk is a regulated, full-service digital asset trading and technology firm that specializes in market making, OTC, and treasury management services.

With offices globally, we have engineered a trading infrastructure that integrates more than 120 centralized and decentralized exchanges. Combining proprietary technology with significant experience from traditional markets and algorithmic trading, Flowdesk brings control and transparency to digital asset markets.