Senior Application Security Engineer

Nabla; Paris; On-site; EUR 90,000 - 150,000; Full time

Job summary

Nabla in Paris is seeking a Senior Security Engineer to bring AppSec expertise to product squads and strengthen security across cloud, CI/CD, and AI features. You’ll own threat modeling, code reviews, vulnerability triage, and secure-by-default libraries, partnering with developers to build robust protections for PHI and patient data.

The role blends hands-on engineering with security design and cross-team collaboration.

Qualifications

• 5 to 8+ years in security engineering, including at least 2 to 3 years in application or product security
• Deep understanding of modern web and API security: OAuth 2.0 / OIDC, session and token design, multi-tenancy, OWASP Top 10 and API Top 10
• Strong coder, able to read and fix production code (Kotlin/Python) and automate in Python
• Experience running threat modeling and security design reviews in CI with a real triage loop
• Excellent communicator who earns developers' trust and works with engineering, compliance and IT
• Fluent in French and English (oral and written)

Responsibilities

• Partner with product squads as their go-to security engineer: design reviews and per-feature threat modeling
• Secure authentication/authorization surfaces (OAuth clients, tokens, multi-org tenancy) and identify access control flaws
• Triage and prioritize findings from SAST/SCA/secrets/IaC scanners; drive backlog down
• Secure AI/LLM features: prompt injection, permission scoping, PHI leakage controls
• Run external testing program: scope pentests, validate fixes, manage vulnerability disclosure
• Build secure-by-default guardrails and secure coding guidelines

Skills

OAuth/OIDC

API security

Kotlin

Python

Threat modeling

CI/CD security

Bilingual FR/EN

Tools

SAST

SCA

Secrets scanning

IaC scanners

Code review tooling

Job description

About NablaNabla delivers a unified clinical AI platform used by healthcare organizations across specialties and care settings. The platform includes:

About NablaNabla delivers a unified clinical AI platform used by healthcare organizations across specialties and care settings. The platform includes:Ambient AI documentation that captures clinical conversations and generates structured notes.AI-powered dictation and clinical workflow tools embedded directly within EHR systems.Agentic AI capabilities that support multi-step clinical and administrative tasks.Enterprise-grade infrastructure built for secure deployment across health systems.About The RoleWe are scaling our healthcare AI platform, with more products, integrations and AI agents, and more protected health information (PHI) flowing through them. To keep pace, we're growing our security engineering team and looking for an exceptional Senior Security Engineer.Our cloud infrastructure handles highly sensitive healthcare data, so security is core to everything we do. Our engineers already ask the right questions every day: can we use a one-time token here? How long should it live? How do we scope this OAuth Client?You'll work directly with our Lead Security Engineer to bring real AppSec expertise into the product squads, and to strengthen security well beyond them.This is a hands-on, high-impact role. About half your time goes to AppSec, but it is deliberately a broad security engineering role, not a pure code-review or pentest job. You'll regularly cross into platform and cloud, CI/CD and detection, and you'll own problems from start to finish. Code scanning, SCA and AI-driven code review are already running, but there is no AppSec process to undo. The threat-modeling practice, the security review loop, the triage rhythm and the secure-by-default libraries don't exist yet. You'll build them and run them.If you're pragmatic, love working shoulder to shoulder with developers, and want your work to protect patients' most sensitive data, this role is for you.Responsibilities

• Partner with the product squads as their go-to security engineer: design reviews, per-feature threat modeling, and fast, opinionated answers on authN/authZ, tokens and session design.
• Secure our authentication and authorization surfaces (OAuth clients, one-time codes, multi-org tenancy, the Core API user API, embedded/postMessage SDKs) and hunt for BOLA, IDOR and broken access control before attackers do.
• Run the code-security findings loop: triage and prioritize results from our SAST, SCA, secrets and IaC scanners and AI-driven code review, route them to the right owners with SLAs, and drive the dependency-vulnerability backlog down, fixing issues yourself when that's faster.
• Secure our AI/LLM features and internal agents, covering prompt injection, tool and permission scoping for autonomous agents, PHI leakage, de-identification assurance and model/API egress.
• Run the external testing program: scope and run pentests (web, mobile, backoffice), validate fixes, operate our vulnerability disclosure program, and stand up a bug bounty.
• Build secure-by-default guardrails (secure coding guidelines, hardened libraries and patterns, pre-commit and PR checks) so the secure path is the easy path.

Qualifications

• 5 to 8+ years in security engineering, including at least 2 to 3 years in application or product security, or experience as a software engineer with a strong security focus.
• Deep understanding of modern web and API security: OAuth 2.0 / OIDC, session and token design, multi-tenancy, and the OWASP Top 10 and API Top 10. You can find access-control flaws by reading code.
• Strong coder, comfortable reading and fixing production code (mostly Kotlin and Python, plus web, mobile and desktop clients) and automating in Python.
• Experience running threat modeling and security design reviews, and operating SAST, SCA and secrets scanning in CI with a real triage loop, not just a dashboard.
• Genuine breadth: comfortable moving between an API design review, a supply-chain hardening PR and an incident in the same week, and honest about what you don't know yet.
• Excellent communicator who earns developers' trust and works well with engineering, compliance and IT.
• Full professional fluency in French and English (oral and written).

Nice to have: LLM / AI agent security, mobile app security, pentest or bug bounty experience, GCP / GKE, or experience in healthcare or another regulated industry.Life at NablaWhen you join Nabla, you join a team that is driven by excellence, curiousity, and kindness. Together, we’re committed to making clinicians’ lives easier and improving healthcare experiences for everyone. We believe clinicians should be able to focus on what they were trained to do, caring for their patients, and that no patient should feel their visit was rushed.We work hard and make time to have fun, too. Our #nablabla channel is just as active as #feature-show-off. We support well-being with workday activities at least three times a week; choose from yoga, running, Pilates, or HIIT. We also host regular off-sites, meet up across New York, Paris, San Francisco, and other cities, and keep the chocolate and nuts well stocked.If this sounds like an environment where you’ll thrive, we look forward to reading your application.Our Values at NablaJoining Nabla means being part of a team that shares a commitment to excellence, humility, growth, and inclusion.Every day is a new chance to excelWe aim for nothing less than the best and are willing to put in the effort and dedication required to exceed standards. We learn from yesterday’s failures and do better every day.Stay humbleThere’s no place for ego in our team. Our collective success is more important than individual achievements. We see humility as wisdom — keeping focus on the bigger picture.Feedback is a giftWe embrace feedback and foster a culture of trust and respect that helps everyone grow. We communicate openly about both achievements and challenges, and we actively involve each other in finding solutions.Committed to diversityWe recognize the ongoing challenge of diversity in tech. Our responsibility starts with fostering an inclusive environment where everyone feels empowered to be their authentic selves and do their best work.Diversity & InclusionDiversity and inclusivity are fundamental values at Nabla. We embrace individuals from various backgrounds, including race, gender, educational history, sexual orientation, and beyond.As an equal opportunity employer, we actively seek out and welcome applicants from diverse backgrounds, believing that a wide range of perspectives enriches our team and enhances our ability to innovate and thrive.