Senior Product Engineer: Full-stack with 80% Backend About Longtail Longtail is building an intelligent decision-streaming platform that helps airlines make smarter, faster commercial decisions in real time. Combining automation, proprietary algorithms, AI, and live data, our technology helps airlines optimize pricing, availability, and product flexibility across thousands of routes worldwide.

We’re a fast-growing, international team solving complex, real-world problems at scale.

The Role You’ll help build and evolve our new conversational analytics and intelligent alerting product, as it moves from beta to a scalable, production-ready platform.

This is a full-stack role with roughly 80% backend, 20% frontend. You’ll own features end to end: understanding customer problems, designing solutions, building and deploying them, and supporting them in production.

A key challenge on this team is building AI-native software customers can trust.

We’re looking for someone with

7+ years of engineering experience , including time spent operating production systems, not just shipping them.

What You’ll Do

Design and build backend services, APIs, and customer-facing capabilities: including conversational analytics, intelligent alerting, reports and saved analyses, and AI-powered/agentic workflows

Own features end to end, from customer problem through to production

Build reliable, asynchronous workflows with orchestration, error handling, recovery,



and observability baked in

Integrate with data, analytics, and AI model platforms

Design resilient systems that handle failures gracefully

Contribute to the React frontend when a feature calls for it

Improve testing, observability, security, and performance across the platform

Make pragmatic technical decisions as the product evolves, and help shape engineering standards and architecture as we grow

What We’re Looking For You're a strong backend engineer who:

Has built and operated production SaaS products

Has strong API, database, and SQL skills

Understands distributed systems, asynchronous processing, and failure modes

Cares about reliability, observability, security, and maintainability

Uses AI-assisted development tools such as Claude Code, OpenAI Codex, or similar, while applying strong engineering judgement

Working at Longtail We’re a collaborative, distributed team that values transparency, ownership, clear communication, and sustainable ways of working. You’ll have the autonomy to make meaningful technical decisions. We’re committed to building a respectful and inclusive workplace where people can do their best work.

Competitive Package with base + bonus + equity + Benefits (Private health insurance and Pension contribution, Learning and Development budget, Childcare, transport and meal vouchers…).

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📌 Senior Product Engineer (Madrid)
🏢 Longtail Technologies
📍 Madrid