Node.js Developer with AI experience (AdTech)

Sigma Software

About The Position

Sigma Software is seeking a Middle/Senior AI and Back-End Developer to help transform a global AdTech product into a modern, AI-enabled ecosystem. The role contributes to a Platform-First architecture built around reusable microservices, serverless infrastructure, and intelligent automation. The customer is a Sweden-based AdTech company whose self-serve advertising platforms automate direct transactions between advertisers and premium global publishers. The product serves globally recognized publishers and processes millions of advertising transactions worldwide. The project is transitioning an existing AdTech ecosystem from monolithic and client-specific implementations to a scalable, API-driven, multi-tenant platform. The team builds cloud-native solutions using AWS serverless technologies and introduces AI-assisted automation, recommendation systems, workflow optimization, data enrichment, and LLM-powered capabilities across the advertising lifecycle. The developer will build and maintain back-end microservices and AI-enabled services with TypeScript and Node.js, design and integrate AI and LLM-powered features, and develop scalable serverless solutions. They will work with cross-functional teams on API-first architecture, contribute reusable engineering components and standards, and help ensure service performance, reliability, observability, tenant data isolation, and quality. The role also supports platform transformation, technical decision-making, and continuous improvement.

Requirements

At least 7 years of commercial experience as a back-end developer.
Strong hands-on experience with TypeScript and Node.js.
Experience building API-first microservice architectures.
Practical experience integrating AI services, LLM APIs, or AI-assisted workflows.
Hands-on experience with AWS serverless technologies, including Lambda, API Gateway, DynamoDB, and EventBridge.
Understanding of RESTful and GraphQL APIs.
Knowledge of prompt engineering concepts and AI integration approaches.
Understanding of multi-tenant architectures and logical data isolation principles.
Interest in AdTech products, automation, and AI-driven optimization.
Upper-Intermediate or higher English level.
Strong analytical and problem-solving skills.
Proactive, ownership-driven mindset.
Ability to collaborate effectively within distributed international teams.
Strong communication skills and attention to engineering quality.

Nice To Haves

Experience with machine learning and AI experimentation projects.
Exposure to recommendation systems or data intelligence platforms.
Experience working with vector databases.
Familiarity with Infrastructure as Code tools such as Terraform or CloudFormation.
Understanding of observability and monitoring practices in distributed systems.
Experience working with scalable cloud-native architectures.
Interest in innovation, experimentation, and continuous learning.

Responsibilities

Develop and maintain high-performance back-end microservices and AI-enabled services using TypeScript and Node.js.
Design, implement, and integrate AI- and LLM-powered platform features.
Build scalable serverless solutions using AWS Lambda, API Gateway, DynamoDB, and EventBridge.
Collaborate with cross-functional teams on API-first architecture and OpenAPI specifications.
Ensure tenant data isolation and compliance with established AdTech data models.
Contribute to reusable libraries, templates, AI integration patterns, and engineering standards.
Participate in code reviews focused on performance, reliability, observability, and service quality.
Translate product and AI feature requirements into scalable technical solutions.
Support platform transformation toward automation, standardization, and intelligent reusability.
Contribute to continuous improvement initiatives and technical decision-making processes.