Senior Backend Engineer | Cybersecurity AI AppSec

United States Digital Space LLC; Paris; Hybride; EUR 90 000 - 130 000; Plein temps

Avantages offerts par ce poste

Significant equity

Top-tier health insurance

Meal vouchers

Gym subscription

Learning budgets

Premium equipment

Open-source time

Conference presentations

Résumé du poste

United States Digital Space LLC in Paris is seeking a Senior Backend Engineer to join a security-focused research team. You will champion innovation and translate research into production-grade solutions that scale.

You will design autonomous scanning systems, build a robust detection engine, and integrate AI-driven testing to improve coverage while controlling false positives across a Kubernetes-based platform.

Qualifications

• 4+ years of experience in backend engineering, security research, or applied R&D in a product environment.
• Strong software engineering fundamentals and ability to work across domains (systems, networking, web architectures)
• Proficient in at least one backend language (Python, Go, or similar)
• Experience designing and shipping production systems with measurable impact
• Ability to translate complex ideas or research into reliable, scalable implementations
• Strong analytical mindset, with a focus on pragmatism and impact
• Comfortable collaborating across engineering and security to deliver end-to-end solutions

Responsabilités

• Agentic scanning systems: Build systems that autonomously explore applications, maintain context, and execute complex testing strategies.
• Security detection engine: Design and implement reliable, production-grade vulnerability detection logic (injection, auth issues, business logic flaws, etc.).
• AI-driven testing: Integrate LLMs and structured reasoning into scanning workflows to improve coverage and reduce false positives.
• Distributed infrastructure: Work on systems that orchestrate thousands of concurrent scans (Kubernetes, queues, resource management).
• Performance & reliability: Ensure scans are fast, deterministic, and cost-efficient despite high complexity and concurrency.
• Core platform design: Contribute to architecture decisions around memory systems, execution environments, and data models.

Connaissances

Backend engineering

Security research

Distributed systems

Performance optimization

Cross-functional collaboration

Outils

Python

Go

Kubernetes

PostgreSQL

Kafka

Terraform

GitLab CI

Playwright

Description du poste

Location: Paris (75002) | Hybrid (2 days remote/week)

About the company

Join the company, a fast-growing leader in AI-powered cybersecurity. Our mission-driven engineering team (18 engineers, 4 technical leads, 3 product owners) is dedicated to redefining application security with cutting-edge detection and automation.

We operate at the forefront of technology and research from our Paris office.

About the Role

As a Senior Backend Engineer you will work in a team with talented security researchers. You'll champion innovation, and ensure research translates into impactful production solutions.

What You'll Do

• Agentic scanning systems: Build systems that autonomously explore applications, maintain context, and execute complex testing strategies.

• Security detection engine: Design and implement reliable, production-grade vulnerability detection logic (injection, auth issues, business logic flaws, etc.).

• AI-driven testing: Integrate LLMs and structured reasoning into scanning workflows to improve coverage and reduce false positives.

• Distributed infrastructure: Work on systems that orchestrate thousands of concurrent scans (Kubernetes, queues, resource management).

• Performance & reliability: Ensure scans are fast, deterministic, and cost-efficient despite high complexity and concurrency.

• Core platform design: Contribute to architecture decisions around memory systems, execution environments, and data models.

Our Tech Stack & Focus

• Languages: Python (primary), Go (performance/network components)

• Runtime: Containerized workloads on Kubernetes (EKS), supporting long and resource-intensive scans

• Scaling: Kubernetes Jobs & queue-driven autoscaling

• Web Automation: Playwright + headless Chromium

• Data: PostgreSQL, S3-compatible object storage, Redis (limited use)

• Messaging: Kafka

• Observability: OpenTelemetry, Grafana Cloud

• CI/CD & Infra: GitLab CI, Terraform

Perks & Benefits

• Significant equity (Stock Options/BSPCE) - become a core stakeholder in the company's journey

• Top-tier health insurance with Alan

• Meal vouchers with Swile

• EGYM Wellpass sport subscription

• Continuous learning: budgets for books and online courses

• Premium equipment to support your work

• Dedicated time for open-source projects

• Present research at top international conferences (RSAC, BlackHat, DEFCON, BSides, APIDays)

About You

• 4+ years of experience in backend engineering, security research, or applied R&D in a product environment

• Strong software engineering fundamentals and ability to work across domains (systems, networking, web architectures)

• Proficient in at least one backend language (Python, Go, or similar)

• Experience designing and shipping production systems with measurable impact

• Ability to translate complex ideas or research into reliable, scalable implementations

• Strong analytical mindset, with a focus on pragmatism and impact

• Comfortable collaborating across engineering and security to deliver end-to-end solutions

Nice to have:

• Experience in application security (web security, pentesting, bug bounty, etc.)

• Exposure to AI/LLM-based systems

• Familiarity with browser automation or large-scale distributed systems