Fullstack Engineer

Description nSure.ai is the payment fraud prevention provider of choice for Crypto, Gaming and Gift Cards. We offer a managed service based on adaptive AI that deploys, for each customer, a dedicated model trained on their data. Focusing on behavioral patterns - the most accurate and uniquely effective way to mitigate modern scalable fraud - our solution takes a fundamentally different approach to detecting fraud and preventing it from happening. Our customers benefit from the highest-efficacy decisions delivered in under 500 ms, with up to 98% approval rates and a chargeback guarantee, generating zero-risk net incremental profit. We’re looking for a Fullstack Engineer to join our team and push forward the technology that powers our fraud prevention engine. In this role, you’ll be responsible for evolving the logic, infrastructure, and performance of our systems, spanning both frontend interfaces and high-performance backend services. You’ll design and build user-facing features and resilient backend services end to end, improve latency and reliability at scale, and contribute to the architecture of a distributed microservices ecosystem. This is an opportunity to make a direct impact on our product, performance, and customers in a fast-moving startup environment where ownership, initiative, and curiosity truly matter. Requirements BSc in Computer Science, Software Engineering, or a related field, or equivalent practical experience. 6+ years of fullstack development experience Experience building scalable, user-facing applications using modern libraries and frameworks Experience with at least one NoSQL document store (e.g., MongoDB, Couchbase) Experience designing and implementing RESTful APIs Strong testing mindset and experience with automated testing frameworks A proactive, curious, and problem-solving mindset with a strong sense of ownership Fluent English (written & spoken) Nice to Have Hands-on experience with at least one streaming or message/event system (Kafka, RabbitMQ, AWS SQS, etc.)] Background in payments, fintech, or fraud prevention Responsibilities Design, develop, and optimize full-stack features, including frontend components and backend services in a modern microservices architecture Build and maintain low-latency APIs that power real-time decisioning, and develop responsive user interfaces Improve system reliability, scalability, and security through engineering best practices Write clean, maintainable, and well-tested code (unit + integration tests) Collaborate in architecture discussions, influence decisions, and drive technical improvements