Senior JavaScript Security Researcher

About the Job

Title: Senior JavaScript Security Researcher

Position: Full-time | 40 hours per week

Location: Amsterdam, Netherlands | Work From home (2-3 days per week in the office)

Salary Range: 80.000,- to 100.000,- annually

At ThreatFabric, we help the world's leading banks stay ahead of fraudsters, scammers, and cybercriminals. Our technology protects millions of users every day by detecting fraud, malware, and emerging attack techniques before damage is done. As a Senior JavaScript Security Researcher, you'll explore new browser capabilities, uncover detection methods, and turn cutting-edge research into real-world protection used at global scale. Your discoveries won't remain on a whiteboard, they'll directly help safeguard people and businesses around the world

As a senior JavaScript Security Researcher, you’ll be responsible for maintaining our FRS web SDKs. Next to that you’ll be driving the new (detection) capabilities of our SDK. This includes detecting and investigating fraud patterns & trends. You’ll be working closely with Threat Analysts and Product teams to enhance fraud detection. Part of your job is exploring and experimenting with (new and upcoming) browser APIs, and research how these APIs can be used to create new and novel detections mechanism. This requires a creative and out-of-the-box mindset. Proven experience with browser and JavaScript security research is a plus.

The position

You should have the ability to research, develop, manage, test, and deploy browser-based JavaScript code in the following areas:

• Latest browser fingerprinting tactics
• Ability to research the underlying working of browser APIs
• Ability tocome up withnovel to use these APIs for detection; this includes looking for anomalies, side channels, and other side effects of these APIs
• Creating a production ready web SDK

Your daily work is to collaborate with the behaviour and device risk analytics tech team including backend engineers, data scientists and product managers.

You are expected to be able to work with minimal guidance as lead research and JavaScript engineer.

Since you will be working in a startup environment, passion and motivation are key to success and pleasure at work.

Responsibilities

Your key responsibilities will include:

• Maintaining our FRS web SDKs
• Driving the new (detection) capabilities of our SDK
• Detecting and investigating fraud patterns & trends
• Working closely with Threat Analysts and Product teams to enhance fraud detection
• Exploring and experimenting with (new and upcoming) browser APIs
• Researching how these APIs can be used to create new and novel detections mechanism

What We Offer

• A 12-month employment contract with the intention to extend. Subject to mutual satisfaction, this may lead to a permanent position.
• A competitive salary that reflects your skills and experience with a salary range between: 80.000,- to 100.000,- annually.
• 25 Holidays per year
• 8% holiday allowance (included in annual salary).
• A Pension Scheme.
• A stimulating and supportive work environment that encourages growth and development.
• The opportunity to make a meaningful impactina rapidly growing tech company.
• Flexible Remote / Hybrid work from home options to promote work-life balance.
• Flexible working hours.
• ActiveThreatFabric events and FitFabric bootcamps.
• Active knowledge sharing huddles.

Skills and qualifications

• 8+ years relevant experience in JavaScript and or framework development.
• Familiar with Browser APIs including APIs needed for browser, mouse, keystroke, scroll dynamics.
• Able to work with Open Source development workflow using git.
• Excellent debugging and problem-solving skills.
• Knowledge of Docker is a nice to-have.
• Proficient English writing skills to document work and communicate project status.
• Be a team player and feel comfortable communicating and collaborating with other team members.

Creativity and Innovation:

• Generates and implements creative, innovative solutions to complex problems.

Problem-Solving:

• Communicates solutions clearly and concisely.
• Possesses a scale-up mentality where flexibility and adaptability are key.

Communication and Interpersonal Skills:

• Communicates technical concepts effectively to diverse audiences.
• Thrives in collaborative environments, fostering teamwork and cooperation.
• Demonstrates empathy and understanding in interpersonal interactions.

Continuous Improvement:

• Actively seeks opportunities to enhance workplace practices and product quality.
• Embraces a mindset of ongoing learning and development to stay ahead of industry trends.

Information Security, Business Continuity & Privacy:

• Proactively engages in maintaining information security and privacy standards.

Why us?

About ThreatFabric

At ThreatFabric, we're not just shaping the future of cybersecurity - we're defining it. With our headquartered in the vibrant city of Amsterdam, ThreatFabric stands at the forefront of combating online fraud, mobile malware, and threat intelligence.

Costly online scams, fraud and malware attacks are rampant. Victims’ life savings are stolen, but so are their confidence and trust. On top of this, financials' brand and reputation are damaged. Many lack online visibility to trigger prompt reaction, and the industry faces regulatory reimbursement pressure.

This is why ThreatFabric provides web and mobile security: scam, fraud and malware detection and prevention, and threat intelligence to be proactive. We help the biggest financial brands protect their customers and their reputation in a world where attacks escalate, and trust erodes.

Join Our Dynamic Team

Ready to dive into the heart of innovation? Our team is a melting pot of talent, passion, and expertise from all corners of the globe. Behind ThreatFabric's success lies a diverse ensemble of technical experts, data scientists, and thought leaders united by a passion for innovation. With a global perspective and a collaborative spirit, our team leverages innovative technology and thousands of data points to deliver security solutions.

As a scale-up, we embrace a scale-up mentality where flexibility, adaptability, and a dynamic approach are essential.

Our Core Values

At ThreatFabric, our culture is defined by three guiding principles:

• One Team: Collaboration fuels our success as we work together to tackle complex challenges.
• Continuous Excellence: We're committed to pushing boundaries and exceeding expectations in everything we do.
• Customers at the Heart: Our customers are not just clients — they're partners. Their success is our priority.

Interested?

Are you as excited about this opportunity as we are? We can't wait to hear from you! Apply through the Personio Link, and let's make innovation happen together! We aim to fill this vacancy Q1 2026.

What's next?

So, you've hit send - what happens now? First, we'll do a screening to ensure we're a good match. If all goes well, you'll be invited for an initial chat with us. Then, there's a second interview, and we may include an assessment to better understand your skills. Ready to take the plunge?

Please note: Pre-employment screening is part of our selection process. We do not accept unsolicited resumes from recruiters or employment agencies.