Top Software Engineer Jobs in Barcelona

Design and build full-stack user interfaces for Elastic Fleet and Streams using TypeScript, React, and Node.js. Own complex projects end-to-end, make architecture and system-design decisions, establish coding standards, conduct code reviews, implement testing and deployment, and collaborate with distributed teams, designers, and product managers. The role focuses on scalable, data-intensive observability interfaces and requires strong communication, user focus, and technical leadership.

Build and deploy production LLM-powered agents that resolve health insurance questions, use member data and tools, interoperate with other AI agents, and support real-time voice conversations. Own evaluation datasets, automated quality monitoring, safety guardrails, and production optimization for resolution rate, answer quality, satisfaction, cost, and latency. Collaborate with care experts and product teams while contributing to technical direction and mentoring engineers.

Develop and enhance iOS applications using Swift and SwiftUI while translating business requirements into technical designs. The role involves making technology and infrastructure decisions, documenting architecture, improving team efficiency, mentoring and identifying engineering talent, and collaborating with technical and business stakeholders in English and Spanish. Experience with APIs, third-party libraries, mobile architectures, Git, DevOps, and published iOS apps is required.

Lead Android application architecture and technical decisions; establish development, testing, monitoring, and change-management processes; collaborate with product teams; reduce technical debt; and improve engineering productivity. The role requires native Android development with Kotlin and Jetpack Compose, plus knowledge of system design, APIs, design patterns, declarative UI, Git, and DevOps. Full-stack, cloud, GraphQL, Firebase, and AI tooling experience are advantageous.

Develop and modernize native iOS applications using Swift and SwiftUI. Improve application performance, scalability, reliability, and delivery efficiency while integrating cloud services and advanced technologies. Collaborate with cross-functional teams, document technical decisions, and apply API design, MVVM, declarative UI, data structures, system design, Git, and DevOps practices. Familiarity with GraphQL, Firebase, full-stack development, and AI tooling is advantageous.

Build and maintain software services and platforms for Stripe Tax. Own projects end to end, including scoping, design, implementation, and production deployment. Collaborate with product, design, infrastructure, marketing, and operations teams; debug production issues; improve operational health; pursue short- and long-term goals; and uphold engineering, security, and technical design best practices.

Own and evolve Trust & Safety systems for trade verification, review processing, and content moderation. Design reliable event-driven workflows, improve monitoring and authentication, diagnose distributed production issues, and lead incident response. Partner with vetting and reviews teams while delivering full-stack services using TypeScript, Node.js, Next.js, Datadog, SQL, and GCP. Help identify systemic risks early and improve team effectiveness through strong engineering practices and AI-assisted development.

Develop and enhance a live drive-thru Voice AI product through software engineering, AI/LLM prototyping and fine-tuning, conversation analysis, system integrations, and customer requirements gathering. Build, test, deploy, and improve production features while evaluating real dialogs and collaborating with customers and internal stakeholders.

Develop and enhance treasury automation products using Python and related backend technologies. Build and improve time-series cash-flow forecasting models, troubleshoot production issues, ensure service reliability and uptime, and improve engineering standards, code quality, and simplicity. The role also involves working with APIs, web and backend systems, Vue.js, SQL, and cloud-native infrastructure.

Designs, develops, and optimizes scalable software systems using Java, Spring Boot, ReactJS, Azure, Kubernetes, and Docker. Ensures software quality, reliability, performance, and scalability while monitoring system metrics and resolving defects. Collaborates with product managers, data engineers, and business leaders, proposes innovative solutions, and mentors junior developers. Requires expertise in distributed systems, PostgreSQL, APIs, testing, concurrency, caching, and AI-assisted development.

Build and operate high-scale JVM-based backend microservices using Java and Kotlin. Own services across architecture, implementation, deployment, monitoring, on-call support, and continuous improvement. Develop event-driven Kafka systems, apply concurrency and performance optimization, design resilient APIs, and operate containerized services with Kubernetes and CI/CD. Improve observability, reliability, automation, and developer productivity while collaborating cross-functionally, mentoring peers, and contributing to technical standards.

Maintain and evolve FAdmin, a mission-critical Ruby on Rails flyer processing system, and related Content Platform tools. Deliver roadmap features end to end, support service desk requests, use AI coding agents to improve delivery and code quality, write automated tests, participate in code reviews, and maintain CI/CD pipelines. The role requires production software development experience, relational database and SQL expertise, and strong English communication.

Build and operate full-stack systems for an AI-powered offensive security platform. Responsibilities include developing React frontends, TypeScript APIs, Kotlin and Go backend services, deploying on AWS, designing scalable systems, optimizing databases, supporting production, and owning features from concept through deployment. The role involves close collaboration with AI and security researchers in a fast-paced remote startup.

Build BLP’s core software across infrastructure, backend, machine learning, and product extension platforms. Responsibilities include operating secure and observable cloud infrastructure, developing performant distributed systems, applying AI to business problems, and enabling customer process automation. The role emphasizes formal reasoning, correctness by construction, maintainable systems, type systems, and functional programming. Work is available onsite in Zurich or remotely within Europe.

Develop and maintain Smadex’s real-time bidding platform using Java and NodeJS. Responsibilities include owning features, writing tested and efficient code, participating in code reviews and architectural decisions, monitoring deployments, ensuring production reliability, and collaborating in an agile engineering team.

Develop and deploy AI-powered 3D graphics solutions for desktop, web, VR, and AR applications using the Evergine engine. Build computer vision and spatial computing models, including NeRF, Gaussian Splatting, point-cloud processing, SAMv2, and GroundingDINO or FlorenceV2. Design scalable algorithms, integrate machine learning frameworks, and collaborate with research and engineering teams in an Agile environment.

Develop and maintain Elasticsearch’s Inference API and plugin framework, integrating internal and external machine learning providers. Responsibilities include API and protocol design, streaming, asynchronous execution, rate limiting, billing integration, provider configuration, testing, open-source contribution reviews, and incident on-call support. The role requires advanced Java expertise, concurrency knowledge, API design skills, and collaboration across distributed engineering teams.

Design, build, and deploy production-grade agentic AI systems: multi-agent orchestration, RAG pipelines, provider integration, LLMOps, observability, and reusable patterns. Embed with client teams, lead design sessions, tune embeddings/vector search, manage cost/latency tradeoffs, and define metrics for accuracy, safety, latency, and cost.

Lead full-stack engineering for scalable digital experiences, building React, Vue, or Angular front ends and .NET, Node.js, or Python back ends. Develop APIs, microservices, reusable components, CI/CD pipelines, automated tests, observability, and infrastructure automation. Set technical standards, guide architecture, mentor engineers, improve reliability and performance, and partner with product, design, and architecture teams. Explore AI enablement, programmable networks, data-driven UX, and developer tooling.

Build backend services, internal developer platforms, tooling, CI/CD systems, testing capabilities, and paved paths using Python. Improve developer experience, productivity, and the software delivery lifecycle through cloud-native, distributed systems and AI-driven workflows. Collaborate with engineering teams as platform users, use data and feedback to measure effectiveness, and influence architecture and technical decisions.

Lead development of scalable web applications and GraphQL APIs using JavaScript, React, Node.js, AWS, and PostgreSQL. Own product architecture, performance, reliability, CI/CD, testing, and engineering standards while mentoring junior developers. Collaborate with stakeholders, provide technical direction, build reusable solutions, and independently drive projects in an agile environment.

Build and maintain developer tools across SDKs, React Email, CLI, MCP, integrations, and supporting backend services. Collaborate on APIs, compatibility, testing, releases, documentation, and shared tooling. Support developers through GitHub issues and pull requests while designing reliable interfaces, error handling, and backward-compatible experiences. The role also involves operating systems with authentication, retries, rate limits, queues, monitoring, and error recovery.

Build and ship native Android features for an AI Neobank using Kotlin. Design clean user journeys for financial services, integrate backend APIs, improve performance and reliability, use analytics to iterate, and implement on-device AI where it improves UX.

Build and operate Alan’s internal agentic AI platform, including web experiences, agent orchestration, secure connectors, isolated runtimes, automations, evaluations, and developer tooling. Own work end to end across React interfaces, APIs, infrastructure, reliability, security, and production operations. Collaborate closely with product teams and internal users to create trustworthy, inspectable AI workflows and scalable platform capabilities.

Build the Ops AI Platform from the ground up, developing reliable AI agents, agent tooling, internal tools integrations, evaluation systems, safety controls, and human-in-the-loop workflows. Scale automation from dozens to tens of thousands of daily tasks while influencing architecture, code quality, product direction, engineering culture, mentoring, and hiring.