Top Software Engineer Jobs in Barcelona

Build production-grade machine learning systems that connect data pipelines to user-facing software. Design robust system architecture, implement model inference, ship resilient full-stack/cloud services, and collaborate on UX-driven solutions using Python, APIs, and AWS.

As a Staff Platform Engineer at Joko, you will lead platform efforts, ensure infrastructure reliability, enhance developer experience, and optimize costs, focusing on security and scalability while collaborating across teams.

Senior engineer owning feature lifecycle: design, architecture, implementation, reliability, and cross-team impact. Lead architecture, SRE/observability, security practices, mentor engineers, and drive product-technical alignment using AI-augmented workflows.

Own and deliver backend identity systems for international markets, shaping technical direction, designing distributed, highly available services, and collaborating with product, design, and analytics. Improve reliability, performance, and operational health; participate in on-call rotation; set code and design standards; mentor and grow engineers; reduce toil and create runbooks/playbooks. Drive cross-team collaboration to meet regulatory and market-specific identity/KYC requirements.

Develop and maintain multi-platform motion control and communication libraries and GUIs for servo drivers. Implement advanced identification and tuning algorithms, optimize performance, produce internal architecture and design documentation, define test plans with QA, and collaborate closely with firmware teams to deliver robust motion control products.

Design, build, and operate reliable, scalable backend services, APIs, and platform components. Lead complex feature development from planning through release, improve service performance, monitoring, alerting, observability, and operational readiness, and collaborate with engineering, product, and QA teams. Serve as a technical contributor for debugging and architecture decisions while mentoring junior engineers and advancing engineering standards.

Build and maintain hardened Ubuntu-based container images and the automated CI/CD pipelines to build, test, scan, sign, publish, and retire them. Integrate upstream open-source projects, ensure security and cloud-native compatibility, collaborate with cross-functional teams, document and share knowledge, mentor colleagues, and contribute to hiring. Work in a distributed agile environment with occasional travel.

Build and scale a blockchain data platform handling petabytes of on-chain data. Design and implement distributed systems, data ingestion/decoding pipelines, and performant SQL processing. Write production code (Kotlin, Go, Java, Rust), improve developer experience, automate operations (including AI-driven automation), and own platform components.

Build and operate Grafana's bare-metal platform: provision storage, networking, and Kubernetes clusters; manage cluster networking, scheduling, and autoscaling; maintain Crossplane compositions and Terraform modules; collaborate with product teams; participate in on-call rotation and datacenter operations.

Lead and deliver Repayment UX features for Affirm's mobile products using React Native. Own quarterly goals, guide engineers through ambiguous problems, collaborate with product/design/analytics, ensure operational reliability (metrics and on-call), improve engineering standards, and mentor teammates to drive high-quality, scalable mobile experiences.

Develop and optimize algorithms for battery and renewable energy projects, analyze market data trends, and ensure algorithm performance.

Own and build the Android client for an AI-first app: implement AI features (chat, vision, voice), optimize performance and memory, design UX for streaming and partial results, integrate backend APIs, instrument analytics/logging, and collaborate with backend and ML teams to ensure stability, security, and scalability in production.

As a Backend Software Engineer, you'll design scalable backend systems, optimize database performance, and collaborate with front-end and DevOps teams.

Contribute to Juju's development, collaborate with teams on distributed systems, debug issues, and enhance cloud automation features.

Senior Staff Software Engineer will develop and integrate cloud-based full‑stack engineering tools for wind-turbine development. Responsibilities include full software lifecycle delivery, collaborating with product and engineering stakeholders, advancing modeling/process improvements, mentoring team members, and ensuring reliable production deployments and testing across frontend, backend, and data layers.

As a Senior Engineer, you'll develop scalable, event-driven backend architectures, design low-latency APIs, and contribute to product development across the stack while optimizing performance and collaborating on AI features.

Design, write, and test clean Java/Kotlin code using design patterns. Build resilient, secure, high-performance services handling millions of requests daily. Monitor, identify, and fix software defects. Work in Agile teams and use Spring Boot/Spring Cloud, Kafka, Docker, and Kubernetes.

Six-month full-time graduate program for final-year or recent engineering graduates. Work in production from day one, contribute to global-scale systems, learn from experienced engineers, and develop foundations in backend development, testing, CI/CD, cloud, and best practices. Potential transition to a permanent role after the program.

Design, implement, and maintain embedded real-time firmware for robotics platforms; own firmware lifecycle from architecture through validation and maintenance; diagnose system-level issues using hardware debugging tools; collaborate with electrical, controls, and software teams; advise leadership on firmware strategy and technical direction.

Design, implement, and optimize scalable application networking features (Ingress, DNS, private connectivity) for Elastic Cloud. Integrate security controls, conduct load and performance testing, troubleshoot network incidents, build tracing tools, and collaborate with cross-functional teams to meet application networking needs and improve observability and operability.

Software Engineers at QuantCo will design and develop scalable solutions, integrate models into client businesses, and improve products based on client feedback.

As an Ubuntu Core Software Engineer, you will design and implement features for the embedded Linux operating system, maintain boot mechanisms, debug system-level issues, and collaborate with a global team.

Build and maintain scalable backend services and web ecosystem components for a high-throughput ad-tech platform. Integrate Agentic AI (LangChain, AWS Bedrock), ensure cloud security (AWS WAF, CloudFront), own features end-to-end from architecture to deployment, and collaborate across teams to preserve data integrity and performance.

Design and implement backend trading services, own features end-to-end (schema, API, tests, UI integration), contribute to real-time infrastructure and client-facing APIs, and write integration tests against real dependencies.

Full-stack Developers at QuantCo build user interfaces for machine learning solutions, collaborating with data scientists and engineers to deliver actionable products.