Senior Software Engineer, AI-Driven SaaS (Barcelona)

Lengow; Bellprat; On-site; EUR 70,000 - 110,000; Full time

Benefits offered by this job

Gym membership discounts via Wellhub.

Private health insurance discounts.

Free organic fruit and coffee.

Job summary

Lengow in Barcelona is seeking a Senior Software Engineer to join the Market Intelligence team. You will design, build, and maintain AI-driven features, collaborating with the Engineering Manager and Product Manager to deliver scalable SaaS capabilities.

You will explore ML/DL models and LLM-based insights, own projects from discovery to delivery, and help modernize a large codebase toward modular, event-driven architecture. Proficiency in English is required.

Qualifications

• Senior-level software engineering experience with a track record of delivering production-grade software.
• Experience using AI coding agents as part of the software development workflow, with the ability to review, validate, and improve AI-generated code.
• Experience with cloud infrastructure and distributed systems (Kubernetes, queues like Celery, Redis).
• Experience building and maintaining SaaS applications in production.
• Strong fundamentals: maintainable, testable, scalable, well-structured code.
• Experience with Domain-Driven Design (DDD) and modular architecture.
• Professional proficiency in English, both written and spoken.

Responsibilities

• Join the Market Intelligence team, working alongside Senior Software Engineers and Software Engineers.
• Design, build, and maintain new products and features for clients, in collaboration with Engineering Manager and Product Manager.
• Explore and develop AI-based solutions, using ML/DL models and LLMs to generate insights and automate product capabilities.
• Take ownership of projects from discovery and technical design through implementation and delivery.
• Contribute to modernization of legacy codebase toward a modern, scalable, event-driven architecture.
• Work on systems that process large amounts of public web data to generate actionable insights.
• Collaborate with UX, Infrastructure, and Data teams, as well as Support and CSMs, to solve customer problems.
• Mentor less experienced engineers and share knowledge to improve engineering practices.

Skills

Senior-level software engineering

AI coding agents

DDD principles

Software engineering fundamentals

English proficiency

Tools

Kubernetes

Celery

Redis

Job description

Lengow in Barcelona is seeking a Senior Software Engineer to join the Market Intelligence team. You will design, build, and maintain AI-driven features, collaborating with the Engineering Manager and Product Manager to deliver scalable SaaS capabilities.

You will explore ML/DL models and LLM-based insights, own projects from discovery to delivery, and help modernize a large codebase toward modular, event-driven architecture. Proficiency in English is required.