Senior Backend (AI / Machine Learning) Engineer

Quick Summary
Role Focus: We are looking for a Senior Backend (AI / Machine Learning) Engineer who can design, build, and deploy intelligent systems in real-world production environments.
Hours: Full-time
Location: Fully remote
EU Time Zone: Looking for people in Europe due to time zone alignment.
GB Language: Native or professional English required. All company and client communication is in English. Spanish is a bonus, as the project is developed for the Latin American market.
4+ years of experience in backend development (Python, Java), combined with hands-on experience in implementing and deploying AI features & Machine Learning models and data pipelines using Python.
Salary Range: €3,000 - €4,000/month gross (dependent on experience level)

About Afternow

We are partners in your digital journey. We bring together strategy, design, and technology to build systems that flex as your future unfolds.

Afternow creates the digital systems brilliant companies are built on. Strategy, identity, web and product design, and technology that scales. Every part of the process supports and informs the other, creating an environment that works today and adapts to wherever the business goes next.

We work primarily with ambitious, digitally focused organizations navigating change. From startups finding their footing, to scale-ups building momentum, to established enterprises reshaping their digital foundations. Our partnerships are built on clarity, craft, and care.

Since 2012, we've grown from our roots on Island Krk, Croatia, to a fully remote team of more than thirty talented people working across the globe. We've partnered with companies including AWS, ThoughtSpot, Progressive, Descartes, ShipBob, Quillbot, Teachable, Crisp, CloudZero, Kinetik, and many more.

4.6 Glassdoor Rating - Join our team and discover why our people consistently rate us so highly.

The Role

We are seeking a Senior Developer with a deep specialization in Machine Learning, Data & AI to help us design, build, and deploy intelligent systems for digital products and platforms. In this role, you will work at the intersection of AI, machine learning, data engineering, and software development. You will be responsible for turning data-driven ideas into reliable production features, from model integration and data pipelines to scalable APIs and cloud-native services. You will collaborate closely with backend engineers, product managers, designers, and client stakeholders to create practical AI and ML solutions that solve real business and user problems.

What You'll Do

• Machine Learning Engineering: Design, implement, and deploy machine learning features in production environments.
• Data Pipelines: Build reliable data pipelines for processing, transforming, and preparing data for ML models, analytics, and intelligent product features.
• API Development: Create internal (gRPC) and external (REST) APIs that allow AI/ML services to be consumed by other applications and systems.
• Experimentation & Optimization: Support experimentation, validation, monitoring, and continuous improvement of ML models and AI-driven features.
• Performance & Scalability: Ensure that ML-powered features are reliable, performant, maintainable, and built to scale.
• Cross-functional Collaboration: Work closely with product managers, backend engineers, frontend engineers, QA, and design teams to define, refine, and deliver intelligent product experiences.
• End-to-end Ownership: Own AI and ML capabilities from technical discovery and prototyping through production deployment, monitoring, maintenance, and iteration.
• Cloud & Infrastructure Collaboration: Work with DevOps and backend teams to deploy, monitor, and scale ML-powered services in AWS cloud environments.
• AI-assisted Development: Use coding agents and AI development tools to improve development speed, testing, documentation, and code quality, while remaining accountable for architecture, security, reliability, and production outcomes.
• AI/ML Service Development: Develop and maintain dedicated AI/ML services, primarily using Python and modern backend engineering practices.
• Model Integration: Integrate, serve, and maintain ML models within scalable backend systems and microservices architectures.
• AI Evaluation & Observability: Define evaluation criteria, test datasets, monitoring, tracing, and quality metrics for AI-powered features. Identify failure modes and implement appropriate safeguards and fallback behaviour.

What We're Looking For

• 5+ years of backend development experience with Python & preferably Java Spring Boot.
• Strong hands-on experience with Python and common ML/data libraries and frameworks.
• Experience building and deploying production-grade machine learning features, not only experiments or notebooks.
• Solid understanding of data pipelines, model serving, APIs, and backend system integration.
• Experience with MLOps tools and workflows, cloud infrastructure, preferably AWS.
• Familiarity with microservices architecture and modern backend engineering practices in Java.
• Understanding of ML lifecycle concepts such as training, evaluation, deployment, monitoring, and iteration.
• Experience with databases, data processing, and structured/unstructured data.
• Familiarity with NLP, RAG, LLMs, recommendation systems, prediction models, vector databases, embeddings, agentic AI systems, tool calling, workflow orchestration, or other applied AI/ML domains is a strong plus.
• Ability to translate complex data and ML concepts into practical, usable product features.
• Strong problem-solving skills and a pragmatic engineering mindset.
• Hands-on experience using AI coding tools or agents as part of a professional software development workflow.
• Experience evaluating AI or ML systems using automated tests, offline evaluations, production metrics, and human feedback.
• Clear communication skills and the ability to collaborate with technical and non-technical stakeholders.
• Languages: Fluent in English to seamlessly integrate with our international team and clientele. Since the product is focused on the Latin American market, being Spanish-speaking is an advantage.

What To Expect

• Flexibility - We have standard 40-hour work weeks. While our agency's working hours are from 9 am to 5 pm CET, you'll have the freedom to work flexible hours and maintain a healthy work-life balance. Just make sure the majority of your working hours fall within that time frame.
• Remote work & Tooling - We operate as a fully remote team. We utilize HubStaff for time tracking and work transparency. We value trust and output, and these tools help us streamline administrative overhead.
• Culture - We value collaboration, openness, a willingness to learn, lead, and a curious nature. Our approach encourages mistakes as long as we are willing to learn from them, fostering a culture where growth comes from understanding and overcoming challenges.
• Autonomy and responsibility - You'll be trusted to get things done efficiently and effectively.

Hiring Process

1. Application review - We'll review your experience, background, and overall fit for the role.
2. Video Call with HR - Initial conversation about fit, availability, and expectations.
3. Second interview with Leadership - If there is a strong match after the first conversation, we'll invite you to a second interview with the Leadership team. This discussion will focus primarily on cultural fit, ownership, communication, and the way you approach collaboration and problem-solving. We may also revisit a few technical topics if anything needs additional clarification.
4. Welcome to Afternow!

Afternow is an equal opportunity employer. We believe diverse teams build better products and create better experiences. We encourage applications from people of all backgrounds, experiences, and perspectives.