Backend Stack Engineer

As a Senior Backend Stack Engineer in the Core Platform Team, you'll be a principal owner of the TMS (Translation Management System) Platform and connected services. That means driving the architecture, reliability, and evolution of services covering translation workflow orchestration, vendor management, customer management, and integrations with our internal services - file transformation, machine translation and many more.

You will set the technical direction for these services: defining how they scale, how they expose capabilities to other teams, and how they maintain the quality bar expected of infrastructure-grade software., * Lead backend architecture decisions: Author architecture decision records, define service boundaries, and ensure services are designed for scalability, resilience, and long-term maintainability.

• Design and enforce API contracts: Define and maintain clean, versioned, well-documented REST APIs consumed by internal teams and, increasingly, by AI agents.
• Drive technical quality: Own non-functional requirements - performance, observability, security, and availability - across the services you lead.
• Own your services end-to-end: From architecture and coding to deployment, monitoring, and on-call support ("You build it, you run it").

Technical leadership & team growth

• Mentor and upskill the team: Support mid-level and junior engineers through code reviews, pairing, and hands-on architectural guidance.
• Set and raise the engineering bar: Champion best practices in testing, code quality, incident response, and continuous delivery across the team.
• Drive DevOps and operational excellence: Own CI/CD pipelines, deployment reliability, and ensure platform services are observable, resilient, and secure.
• Collaborate cross-functionally: Work with product managers and domain experts across the business to shape the platform roadmap and translate real needs into sound technical solutions.

In one year, you'll know you were successful if

• The core platform services you own are more reliable, better documented, and better understood across the organization than when you joined.
• You have led at least one significant architectural improvement that measurably improved scalability, resilience, or developer experience for dependent teams.
• Your APIs and tool interfaces are trusted by both internal engineers and the AI orchestration layer - well-defined, stable, and easy to consume.
• Engineers on the team are measurably better for having worked alongside you - through code reviews, pairing, and the standards you've raised.

• 5+ years of backend engineering experience in production environments, with deep expertise in C#, .NET Core / .NET 8+, ASP.NET Web API, and microservices architecture.
• Proven track record of owning and evolving production services: schema migrations, API versioning, backward compatibility, and long-lived service maintenance.
• Strong experience with distributed systems concepts: event-driven architecture, message queues (Azure Service Bus, RabbitMQ), sagas, idempotency, and eventual consistency.
• Strong experience with AI developer tools (using and building custom agents, skills, instructions).
• Deep proficiency with relational databases (MSSQL and/or PostgreSQL): complex query design, schema design, indexing strategies, and performance tuning.
• Demonstrated experience making and documenting architectural decisions (ADRs, system design, trade-off analysis) with the ability to defend and adapt your choices.
• Hands-on DevOps experience: CI/CD pipelines, Docker, Kubernetes, Azure - with the mindset that owning deployment and operations is part of the engineer's job.
• Experience designing robust, versioned REST APIs consumed by multiple teams, including security considerations (OAuth 2.0, API key management, rate limiting).
• Some frontend exposure (Vue.js and/or TypeScript) - enough to contribute when needed, but the primary focus here is backend and platform.
• A track record of mentoring and uplifting junior engineers - through code reviews, design sessions, and raising the quality bar organically.
• Strong communication skills and the ability to articulate technical decisions to both engineers and non-technical stakeholders. English fluency required.
• Agile, collaborative, and opinionated in a constructive way - you push back when needed and bring others along.

This will make you stand out

• Experience with workflow automation frameworks (Temporal, Inngest or similar).
• Deep observability mindset: structured logging, distributed tracing (OpenTelemetry), alerting strategies, and SLO/SLA ownership for platform services.
• Experience with service mesh, API gateway patterns, or platform engineering practices at scale.

LanguageWire is a global leader in language and content services, dedicated to helping brands achieve their full global potential. Since 2000, we've evolved and built unique technology that enables seamless multilingual communication. Our worldwide network of language experts, together with our intuitive online platform, empowers brands to translate and manage multilingual content effortlessly., You'll join the Core Platform Team, one of the foundational engineering teams at LanguageWire. The team owns and operates multiple services that build up to the TMS Platform. These are the services our whole operation depends on. We value outcomes over output, shared ownership over silos, and continuous delivery over long release cycles. Our stack is built on .NET services, Azure, and modern API patterns., * Flat hierarchies, real responsibility and autonomy, direct feedback, and room to stand up for your ideas. * Internal development opportunities, ongoing support from your People Partner, and an inclusive and fun company culture. * International company with over 300 employees. Offices in Copenhagen, Aarhus, Stockholm, Varberg, London, Leuven, Lille, Paris, Munich, Hamburg, Sophia Antipolis, Atlanta, Finland, and Valencia. * Full-time FlexiWire@home option for remote work. You're always welcome in the office to collaborate and connect. * We take care of our people: Friday Bars, Summer and Christmas parties, and a genuine social culture. * Excellent location in modern offices in Valencia city center, with a rooftop terrace overlooking Town Hall Square. * Private health insurance. * International environment - more than 20 nationalities in the company. * Dog-friendly office, big kitchen with organic fruits, coffee, and snacks, plus a game room (foosball, darts, board games) and bike and car parking.