Scrambly is one of the fastest-growing adtech startups in the world, featured in the AppsFlyer Performance Index and Singular ROI Index in just 3.5 years.

We’re growing 250%+ YoY across revenue, team, product, and technology — fully bootstrapped and profitable.

We’re building the future of app discovery: a reward-powered alternative to the App Store and Google Play. Our loyalty-driven ecosystem connects millions of users with the world’s top apps and delivers unmatched, ROI-focused growth for mobile advertisers.

Our mission is to build a true alternative to traditional app stores — fueled by rewards and data — and create a new, performance-first growth engine for mobile app advertisers.

We are looking for a Senior Backend Engineer to join the team building the core systems behind Scrambly. In this role, you will work across two key areas: user-facing product systems - solving complex scalability challenges for a platform serving millions of users globally, - and the internal platform, covering admin systems, tooling, and back-office automation that power our operations team.

Your focus will be on writing robust, high-performance code and bridging the gap between product requirements and technical reality. You will work within a modern tech stack to ensure our systems remain fast, reliable, and easy to maintain as we grow.

Architecture & Development: Design, build, and maintain highly scalable Node.js (NestJS) RESTful APIs and distributed systems. Ensure seamless frontend integration and drive long-term architectural improvements.

Quality & Mentorship: Champion clean, testable code standards and foster a culture of technical curiosity by mentoring engineers through code reviews and pair programming.

Infrastructure & Performance: Monitor system reliability, resolve bottlenecks, manage containerized application lifecycles, and partner with DevOps to optimize CI/CD pipelines.

Cross-Functional Collaboration: Partner with Product, Design, and QA to translate requirements into robust technical specs, while clearly communicating technical constraints to non-technical stakeholders.

• Experience: 5+ years of software engineering experience, with a strong focus on backend development.
• Tech Stack: Strong proficiency in Node.js and modern frameworks like NestJS.
• System Design: Excellent system design skills and a solid understanding of backend architecture, RESTful APIs, and distributed systems.
• Infrastructure: Experience with cloud platforms (GCP preferred; AWS or Azure acceptable), containerization (Docker), and orchestration/IaC (Kubernetes, Terraform, Helm).
• Databases & Messaging: Proficiency with relational (e.g., PostgreSQL), NoSQL (e.g., Redis) databases, and message queues (e.g., RabbitMQ, GCP Pub/Sub, Redis Pub/Sub).
• Frontend Autonomy: Hands-on experience with React, capable of implementing basic UI features for internal tools independently.
• Collaboration: Strong communication and collaboration skills, comfortable working in a fast-paced team environment.
• English: Upper-Intermediate or higher (B2/B2+, written and spoken). You need to be able to communicate clearly in English to work effectively in an international team and participate in architectural discussions

• Scale: Experience in a B2C startup that has scaled to millions of users.
• Additional Stack: Basic proficiency in Go; able to read, write, and maintain basic Go services without starting to learn from scratch.

• Work on systems where performance optimizations translate to immediate user impact for millions of users.
• A culture of code reviews, knowledge sharing, and mentorship where the best idea wins.
• A fast-paced environment where your code quickly translates into real user value.
• We value the stability and value of what you ship, not just the number of lines of code.

By submitting this application, I agree that my personal data will be collected, processed, and retained by the company solely for the purposes of managing and assessing my candidacy.

Notice: This is a remote position based in Spain.