Senior Full Stack Engineer

Job Description

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. 

The role you’ll play 

As a Senior Full Stack Engineer in the Core Platform Team, you’ll be a principal owner of the foundational microservices that the rest of LanguageWire depends on. That means driving the architecture, reliability, and evolution of services covering authentication, object storage, notifications, email delivery, and integrations with our ERP and CRM systems — the backbone of the entire platform. 

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. You’ll also contribute to our growing Agentic Roadmap, shaping the tool interfaces and integrations that allow AI agents to invoke platform capabilities across the business — a natural extension of the microservices ownership you already hold. 

This is a role for someone who takes genuine pride in the craft of building robust, well-designed systems and who wants to be a multiplier: raising the technical level of the team around them, not just shipping code.

The team you’ll be a part of

You’ll join the Core Platform Team, one of the foundational engineering teams at LanguageWire. The team owns and operates 12 microservices that underpin the entire organisation, covering file storage, authentication, notifications, email delivery, and integrations with our ERP and CRM systems, among others. These are the services every other team depends on.

As LanguageWire invests in AI, the Core Platform Team is also taking on a new function: building the tools and integrations that allow AI agents to interact with our services and automate workflows across departments. As a senior member of the team, you’ll contribute to shaping that roadmap while remaining the backbone of the platform’s reliability and technical integrity. 

We value outcomes over output, shared ownership over silos, and continuous delivery over long release cycles. Our stack is built on .NET microservices, Azure, and modern API patterns. 

If you want to make a difference, make it with us by…

Core microservices ownership 

• Own and evolve foundational services: Take end-to-end ownership of platform microservices (authentication, storage, notifications, integrations), driving their architecture, reliability, and roadmap. 

• Lead backend architecture decisions: Author architecture decision records, define service boundaries, and ensure microservices 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”). 

Agentic Roadmap contribution 

• Build AI agent tool interfaces: Design and expose backend capabilities as well-defined tool schemas (OpenAPI specs, MCP server definitions, function schemas) that AI agents and LLM orchestration layers can reliably consume. 

• Integrate platform services with agentic workflows: Extend existing microservices to support the tool-calling patterns needed for end-to-end AI-driven automation across departments. 

• Apply agent-aware design patterns: Ensure platform APIs are structured for deterministic, reliable invocation by AI agents — with proper input validation, idempotency, and audit trails. 

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 microservices you own are more reliable, better documented, and better understood across the organisation 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. 
• You’ve contributed meaningfully to the Agentic Roadmap, enabling at least one AI-driven workflow that saves real time for an operational team. 

Desired experience and competencies  

What does it take to work for LanguageWire? 

What you’ll need to bring

• 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 microservices: 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. 

• 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 more 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

• Familiarity with AI agent tooling: designing tool/function calling schemas, MCP (Model Context Protocol) server definitions, or OpenAPI specs consumed by LLM orchestration layers. 

• Practical experience with LLM APIs (Anthropic, OpenAI, Azure OpenAI) and how to structure reliable, deterministic tool-calling pipelines. 

• Experience with workflow automation or agentic orchestration frameworks (LangChain, Semantic Kernel, Temporal, Azure Logic Apps, 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. 

Our perks 

• Flat hierarchies, real responsibility and autonomy, direct feedback, and room to stand up for your own 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. Of course, you are always welcome at the office to collaborate and connect with your colleagues. 

• We take care of our people and initiate many social get-togethers from Friday Bars a to Summer or Christmas parties. We have fun! 

• Excellent location in cool and modern office in Valencia city center, with a great rooftop terrace overlooking the Town Hall Square 

• Private health insurance 

• Working in an international environment—more than 20 different nationalities 

• A dog friendly atmosphere 

• Big kitchen with access to organic fruits, nuts and biscuits and coffee. 

• Social area and game room (foosball table, darts, and board games) 

• Bike and car parking 

About LanguageWire  

At LanguageWire, we want to wire the world together with language. Why? Because we want to help people & businesses simplify communication. We are fueled by the most advanced technology (AI) and our goal is to make customer's lives easier by simplifying their communication with any audience across the globe. 

Our values drive our behavior 

We are curious. We are trustworthy. We are caring. We are ambitious. 

At LanguageWire, we are curious and intrigued by what we don’t understand. We believe relationships are based on honesty and responsibility, and being trustworthy reinforces an open, humble, and honest way of communicating. We are caring and respect each other personally and professionally. We encourage authentic collaboration, invite feedback and a positive social environment. Our desire to learn, build, and share knowledge is a natural part of our corporate culture. 

Working at LanguageWire — why we like it:  

“As a Senior Full Stack Engineer at LanguageWire, my day is dynamic and collaborative, particularly within the Machine Learning team. I work closely with Machine Learning Engineers to integrate advanced AI capabilities into our web applications and APIs, aiming to enhance customer experiences through innovative features. I also collaborate with other development teams to ensure seamless integration and alignment of our technology solutions, fostering continuous learning and driving the evolution of LanguageWire's technology.” 

(Cristian, Senior Full-Stack Engineer, Poland) 

“What I enjoy the most about being a QA Engineer at LanguageWire is testing the products we provide to our customers. It feels rewarding to assure the quality and reliability of our designs. I also enjoy the teamwork involved in my job since I collaborate with many people, ranging from developers to product managers and linguists. In this way, I play a role in ensuring our projects' success, which is incredibly gratifying. I love knowing my work influences the outcome of our production of high-quality products for our customers. I also have the opportunity to work with the latest technologies adds an exciting challenge to my role.” 

(Ricardo, QA Engineer, Portugal) 

Yes, to diversity, equity & inclusion 

In LanguageWire, we believe diversity in gender, age, background, and culture is essential for our growth. Therefore, we are committed to creating a culture that incorporates diverse perspectives and expertise in our everyday work. 

LanguageWire’s recruitment process is designed to be transparent and fair for all candidates. We encourage candidates of all backgrounds to apply, and we ensure that candidates are provided with an equal opportunity to demonstrate their competencies and skills. 

Want to know more? 

We can’t wait to meet you! So, why wait 'til tomorrow? Apply today! 

If you want to know more about LanguageWire, we encourage you to visit our Website !