Senior Full-Stack Product Engineer
The posting does not state a salary. This range is our estimate from the role, the location and the stack — treat it as a guide, not an offer.
- Level
- Senior
- Apply from
- Spain
About the role
- Design and build backend services and APIs.
- Contribute to the React frontend when needed.
- Own features end to end from design to production.
- Integrate with AI model platforms and data.
- Focus on reliability and observability in systems.
Skills the posting asks for
- Java
- React
- Spring Boot
- PostgreSQL
- AWS
Summarised from the employer’s posting, which is reproduced in full below.
The employer’s full posting
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 Sightline , Longtail's conversational analytics and intelligent alerting product, as it moves from beta to a scalable, production-ready platform.
This is a backend-focused full-stack role. 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: turning customer intent into secure, observable, explainable, and repeatable production workflows.
We're looking for someone with 7+ years of backend/full-stack engineering experience , including time spent operating production systems, not just shipping them.
What You'll Do
Backend: Java, Spring Boot, Python, FastAPI, MCP
Frontend: React, Vite, Zustand, Vitest, Nginx
AI & Data: Anthropic, OpenAI, OpenRouter, Databricks, PostgreSQL, Amazon Aurora
Infrastructure: AWS, Kubernetes, Docker, Terraform, Kong, Keycloak, OpenTelemetry, New Relic
What We're Looking For
You're a strong backend engineer who:
What Success Looks Like
Within your first few months, you'll:
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, the context to understand why your work matters, and the responsibility to see what you build succeed in production.
We're committed to building a respectful and inclusive workplace where people can do their best work.
Compensation & Benefits
Competitive Package with base + bonus + equity + Benefits (Private health insurance and Pension contribution, Learning and Development budget, Childcare, transport and meal vouchers…).
Interview Process
Intro call → Technical interview → System Design → AI-Assisted Coding Interview → Behavioural interview → Offer.
Ready to Build Something That Matters?
If you want to build AI-powered products that turn complex airline data into better commercial decisions — and solve the engineering challenges required to make AI reliable at enterprise scale — we'd love to meet you.
We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.
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 Sightline , Longtail's conversational analytics and intelligent alerting product, as it moves from beta to a scalable, production-ready platform.
This is a backend-focused full-stack role. 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: turning customer intent into secure, observable, explainable, and repeatable production workflows.
We're looking for someone with 7+ years of backend/full-stack 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 across Sightline's product and platform; 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
Backend: Java, Spring Boot, Python, FastAPI, MCP
Frontend: React, Vite, Zustand, Vitest, Nginx
AI & Data: Anthropic, OpenAI, OpenRouter, Databricks, PostgreSQL, Amazon Aurora
Infrastructure: AWS, Kubernetes, Docker, Terraform, Kong, Keycloak, OpenTelemetry, New Relic
What We're Looking For
You're a strong backend engineer who:
- Has built and operated production SaaS products
- Is comfortable contributing across the stack
- Has strong API, database, and SQL skills
- Understands distributed systems, asynchronous processing, and failure modes
- Cares about reliability, observability, security, and maintainability
- Enjoys owning features end to end and takes ownership of software beyond deployment
- Can turn ambiguous customer problems into pragmatic technical solutions
- Uses AI-assisted development tools such as Claude Code, OpenAI Codex, or similar, while applying strong engineering judgement
What Success Looks Like
Within your first few months, you'll:
- Ship a meaningful customer-facing capability
- Take ownership of a defined area of Sightline
- Improve the reliability or observability of an existing workflow
- Build a strong understanding of our architecture and customer needs
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, the context to understand why your work matters, and the responsibility to see what you build succeed in production.
We're committed to building a respectful and inclusive workplace where people can do their best work.
Compensation & Benefits
Competitive Package with base + bonus + equity + Benefits (Private health insurance and Pension contribution, Learning and Development budget, Childcare, transport and meal vouchers…).
Interview Process
Intro call → Technical interview → System Design → AI-Assisted Coding Interview → Behavioural interview → Offer.
Ready to Build Something That Matters?
If you want to build AI-powered products that turn complex airline data into better commercial decisions — and solve the engineering challenges required to make AI reliable at enterprise scale — we'd love to meet you.
We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.