App Security Expert - Remote

About the role

A partner company, represented by Jobgether, is looking for an App Security Expert based in Estonia to work remotely. The role strengthens application security by designing realistic test environments and evaluating vulnerabilities in traditional and AI-powered applications, with a focus on large language model (LLM) risks such as sensitive information disclosure and excessive agency. It is a full-time, independent engagement of about 40 hours per week.

Key responsibilities

• Design and build application fixtures with representative vulnerabilities or secure implementations, focusing on OWASP risks affecting LLM applications.
• Create realistic test scenarios for LLM security concerns and deterministic test cases with security-context manifests.
• Develop reference solutions and hidden answer keys so AI systems and scanners can evaluate vulnerable versus secure code.
• Assess and refine testing pipelines so synthetic security tasks are realistic, reproducible and technically challenging.
• Build, inspect and secure application codebases, identify advanced vulnerabilities and propose remediation.
• Contribute to security architectures for traditional applications and agent-based systems, and improve AI-powered static application security testing (AI-SAST).
• Document findings, testing approaches and remediation recommendations, and collaborate with distributed teams.

Required profile

• At least 5 years of experience in application security, secure software development, cybersecurity engineering or a related field.
• Proven ability to design, implement, secure and test application codebases.
• Experience designing or evaluating security architectures for traditional software and agent-based systems.
• Excellent technical writing and communication skills; able to work independently in a fully remote setting.

Required skills

• Strong knowledge of LLM security, including prompt attacks, sensitive information disclosure and excessive agency.
• Experience with AI-powered static application security testing (AI-SAST), automated code analysis or AI-assisted security evaluation.
• Familiarity with OSWE-level application security concepts and vulnerability research.
• Deterministic testing, synthetic security fixtures or structured evaluation frameworks are highly desirable.

What we offer

• Hourly pay of $40 to $80 depending on experience and expertise.
• Fully remote work, starting as soon as possible.
• Initial 12-month long-term contract, with flexible independent engagement as a freelancer or contractor.
• Work on cutting-edge challenges in application security, LLM vulnerabilities and agent-based architectures.