Top Software Engineer Jobs in Barcelona

Lead architecture and modernization efforts to migrate legacy monoliths to a Java/Kotlin/Spring stack, design patterns for zero-downtime displacement, mentor engineers, build and transition services from Go, collaborate with product across timezones, ensure observability with Grafana and tracing, enforce robust testing, and leverage agentic tools to accelerate refactoring.

Build and operate cloud platform services: implement features in production, own scoped projects from requirements to production, participate in design and code reviews, operate services including on‑call, automate repetitive work, and collaborate asynchronously with distributed teams.

As a Staff Software Engineer, you'll shape technical strategy, build integrations and services, lead operational processes, and mentor your team, ensuring high-quality code and fostering collaboration across teams.

As a Staff Full Stack Software Engineer, you'll guide technical strategy, mentor engineers, and ensure quality in full stack development while collaborating across teams.

Develop and enhance MAAS core components, improve architecture, collaborate across teams, and ensure high standards in documentation and CI practices.

Lead development of vector similarity search capabilities in Elasticsearch, including designing algorithms and data structures, implementing modern Java features, improving search relevance and performance, fixing bugs, and collaborating with a globally distributed engineering and open-source community. Own technical initiatives from design through delivery, guide cross-functional projects, and serve as an expert on Elasticsearch vector search.

Lead development of Elasticsearch vector search capabilities, including designing and implementing new features, algorithms, and data structures; improving search relevance, speed, and scalability; fixing complex bugs; and contributing to Apache Lucene. Collaborate with a globally distributed engineering and open-source community, provide technical leadership, review code, and guide cross-functional initiatives. Develop modern Java software and independently drive projects from technical design through delivery.

Lead Elasticsearch search relevance and vector search initiatives, designing and implementing new search features, algorithms, and data structures in modern Java. Improve performance, scalability, and relevance; resolve complex bugs; collaborate with a globally distributed engineering and open-source community; review code, guide technical decisions, and own projects from design through delivery.

Lead Elasticsearch search relevance initiatives, designing and implementing search features, algorithms, and data structures while resolving complex bugs. Improve vector search capabilities, performance, scalability, and code quality using modern Java. Collaborate autonomously with globally distributed engineers and open-source contributors through design, code review, issue triage, and cross-functional initiatives.

Lead development of Runware’s AI platform, including scalable backend APIs, SDKs, developer tools, and inference orchestration systems. Design high-performance distributed architectures, optimize image and video model integrations, improve reliability and observability, shape technical direction, and mentor engineers. Collaborate across platform, infrastructure, and product teams to deliver robust developer experiences and maintainable systems.

Design, build, and own scalable backend services, APIs, and high-performance web frontends for an autonomous procurement platform. Improve reliability, security, and performance, implement async task pipelines, and collaborate with product and design. Mentor juniors, participate in code reviews, and leverage AI-assisted tools while shipping iteratively in a globally distributed, async-first team.

Lead technical direction and hands-on execution for major products and systems. Design scalable backend, frontend, API, database, and cloud solutions; write and review code; make architecture trade-offs; resolve production issues; improve testing, security, observability, and engineering practices; lead critical initiatives and mentor engineers across distributed international teams.

Lead technical direction and hands-on execution for major software products and systems. Design scalable backend, frontend, API, database, and infrastructure solutions; write code; make architecture trade-offs; resolve production issues; improve engineering quality; lead critical initiatives; and mentor engineers across distributed international teams.

Owns technical direction and execution for major products and systems. Designs scalable, reliable architectures across backend, frontend, APIs, databases, and infrastructure; writes code; leads architecture decisions; resolves complex production issues; improves engineering quality; drives critical initiatives; and mentors engineers across teams.

As a Senior Software Developer/Scrum Master, you will lead the development team through the software lifecycle using Agile methodologies, design high-quality code in C#, and ensure continuous improvement while facilitating team dynamics.

Lead the migration of software from C# to Rust, design high-performance systems, and mentor developers while maintaining coding standards and software quality.

Design, build, test and deploy high-performance, multi-region microservices and RESTful APIs using cloud-native tooling. Modernize real-time content systems, troubleshoot production issues, collaborate with stakeholders, and mentor teams while following Agile/Scrum practices.

Design and evolve core cloud platform services, control-plane components, and internal APIs. Build platform abstractions, drive architectural initiatives (gRPC migration, eventing), write production-grade Go code, improve scalability and developer experience, and support production systems and incident response when needed.

Design and evolve core cloud platform services, control-plane components, internal APIs, and platform abstractions. Build production-grade Go services and tooling, drive architectural initiatives such as gRPC migration and eventing foundations, and improve scalability, reliability, and developer productivity. Collaborate across engineering teams, support production systems and incident response, and drive long-term technical solutions for managed cloud and enterprise deployments.

Design and scale backend systems, APIs, and services for Nango’s open-source developer infrastructure platform. Build APIs, SDKs, UIs, and runtime systems, optimize performance and reliability, solve integration challenges with customers, shape the roadmap, and maintain the open-source repository. The role requires strong ownership, product thinking, developer empathy, communication, and autonomy in a remote-first startup environment.

Design, develop and operate scalable Python backend services, REST APIs and cloud-native infrastructure for connected health devices. Improve performance, observability, deployment pipelines and system reliability; collaborate across Product, AI, Embedded and Frontend teams; mentor engineers and drive architectural decisions through production deployment.

Lead and evolve QA strategy and automation frameworks across backend, frontend and embedded systems. Design and maintain automated tests, integrate into CI/CD, define release acceptance criteria and quality gates, perform functional/regression/integration testing, analyze production issues, monitor quality metrics, and promote a quality-first culture.

The Fullstack Software Engineer will design and build the core billing platform, handling payments and transactions while ensuring system scalability and reliability.

As a Fullstack Software Engineer, you will develop the core billing engine, ensuring accurate transaction processing, integrating with systems and platforms, and collaborating with teams to maintain a unified platform experience.

As a Fullstack Software Engineer, you'll engineer systems for payroll and benefits, automate workflows, and collaborate with HR teams to improve user experience. You will work with modern technologies to simplify complex business processes.