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

Our Tech Stack
Backend: Java, Spring Boot, Python, FastAPI, MCP
Frontend: React, Vite, Zustand, Vitest, Nginx
AI & Data: Anthropic, OpenAI

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