Top Software Engineer Jobs in Barcelona

Build full-stack data and AI applications, platform services, APIs, GenAI capabilities, and cloud-native infrastructure for Sanofi’s OneMesh ecosystem. Responsibilities include developing with React, TypeScript, Node.js, Python, and FastAPI; implementing RAG and agent orchestration; deploying on AWS and OpenShift; maintaining Terraform infrastructure and CI/CD pipelines; and ensuring security, observability, reliability, and production readiness. The role collaborates with data, machine learning, product, and business 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.

Develop and maintain high-performance full-stack software across the complete lifecycle, including architecture, implementation, testing, debugging, and continuous maintenance. Translate requirements into technical specifications, write robust C# code, ensure test coverage, participate in Agile planning, conduct code reviews, and use AI-supported tools to improve development and troubleshooting. The role requires advanced expertise with C#, WPF, .NET, SQL Server, Entity Framework, Git, and Agile methodologies.

Provides technical leadership for Elastic UI, a React and TypeScript design system used across Elastic products. Owns component architecture, APIs, theming, accessibility, versioning, migrations, performance, and long-term maintainability. Partners with design and engineering teams, drives adoption, mentors engineers, leads architectural decisions, and improves developer experience. The role also explores AI-assisted design-to-code, accessibility, and migration workflows while maintaining high quality standards.

Develop and maintain features for Smadex’s real-time bidding platform using Node.js and Java. Responsibilities include writing tested code, participating in code reviews and architectural decisions, monitoring deployments, supporting production reliability, and collaborating in an agile environment. The role requires Linux, Git, Docker, Docker Compose, testing, and CI/CD experience, with AWS and in-memory database knowledge as advantages.

Build and scale healthcare insurance products across claims management, insurance offers, and customer enablement. Design reliable systems, collaborate across teams, contribute to product decisions, mentor engineers, lead complex projects, and support hiring. Work with Python, JavaScript, React, React Native, PostgreSQL, and related web technologies in a product-focused engineering environment.

Build and operate full-stack software for clinical trial products, including backend services, APIs, data pipelines, React applications, and production AI/LLM features. Establish AI-assisted development standards, prompt engineering patterns, evaluation frameworks, and code quality gates. Support observability, reliability, CI/CD, infrastructure collaboration, secure regulated development, testing, code reviews, and mentoring.

Develop and operate full-stack software for clinical-trial products, building backend services, APIs, streaming pipelines, and React applications. Integrate production AI and LLM capabilities, establish prompt engineering and evaluation practices, and improve reliability, observability, CI/CD, security, and compliance. The role includes troubleshooting, code reviews, mentoring, and shaping AI-assisted engineering standards in a regulated environment.

Develop privacy, anti-tracking, and phishing protections for Firefox and improve the Gecko browser engine. Build performant, low-latency, maintainable software in C++, JavaScript, and Rust while collaborating asynchronously with a distributed team. The role requires independently scoping and delivering complex features, with emphasis on memory safety, multithreaded architecture, data streams, web privacy, and browser security.

Design and deliver internal systems, Go services, APIs, data models, dashboards, visualizations, and LLM-powered workflow features. The role includes writing specifications, estimating work, code reviews, testing, documentation, security, performance, accessibility, and collaboration with nontechnical stakeholders. The engineer will handle sensitive people data, mentor colleagues, and improve team practices in a globally distributed environment.

Designs and scales real-time identity verification services, including APIs, event-driven systems, architecture, CI/CD, observability, and reliability foundations. The role owns technical architecture, raises engineering standards, mentors engineers, collaborates with ML and product teams, and delivers secure, maintainable, high-throughput services for internal and external customers.

Design, develop, and maintain high-quality web applications using CodeIgniter and PHP. Collaborate with cross-functional teams to define and ship features, ensure application performance and quality, identify and fix bugs, and maintain code quality and automation.

Builds software solutions for end users as a general full-stack engineer. The role emphasizes collaboration, ownership, accountability, fast-paced execution, adaptability, multitasking, rapid learning, and an ambitious, outcome-driven approach.

Design, develop, debug, and improve Elastic’s hosted control-plane cloud offerings. Lead technical architecture, development best practices, scalable and reliable foundation work, automation, quality initiatives, and cross-team technical planning. Collaborate with distributed engineering, support, and product teams to diagnose complex issues and guide feature development.

Build and operate production AI infrastructure powering intelligent agents at scale. Develop high-performance Rust services for model inference, orchestration, and execution; design scalable distributed systems; establish MLOps, observability, guardrails, and failure recovery; and optimize latency, throughput, reliability, and cost. Partner with agent systems and infrastructure teams to turn prototypes into hardened services serving millions of users.

Build and maintain internal and public-facing APIs and services powering the Web App and developer experience. Develop API functionality, Admin API systems, WebSocket and REST behavior, and usage and billing integrations with Stripe. Investigate production issues and security vulnerabilities, write and review tested code, make technical decisions, and collaborate across engineering, Product, and Design teams.

Leads performance engineering and automation for Akamai’s cloud compute infrastructure. Designs distributed testing and benchmarking frameworks, establishes performance standards, optimizes CI/CD pipelines, analyzes telemetry, resolves bottlenecks, and mentors engineers. The role requires expertise in Python, Linux, Bash, Jenkins, Git, automated testing, and performance validation across hardware and software platforms.

Develop scalable performance-testing frameworks and automated benchmarking suites for distributed cloud platforms. Design regression, load, stress, and performance tests; establish hardware validation standards and performance thresholds; monitor latency, throughput, SLAs, and infrastructure bottlenecks; and integrate testing and performance gates into Jenkins CI/CD pipelines. Collaborate with developers, SREs, and datacenter teams to improve test architecture, resolve performance issues, and deliver actionable insights from telemetry and data analysis.

Lead the development of Runware's serverless platform by building core systems for AI workload management and providing technical guidance to the team.

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.

Develop cross-platform telecommunications applications for network optimization, automation, performance monitoring, data analytics, and visualization. Work with multidisciplinary telecom and software teams using Python, SQL, cloud technologies, Elastic Stack, and modern software development practices across 2G, 3G, 4G, 5G, and Open RAN environments. Troubleshoot development and production issues and support projects for wireless operators and vendors across Spain and Europe.

Build AI agents, reusable agent platforms, and automated workflows across the software development lifecycle. Develop integrations with codebases, APIs, MCPs, internal tools, and engineering systems. Prototype and scale AI capabilities, while designing context management, orchestration, verification, and human-in-the-loop mechanisms for safe, reliable automation. Measure agent effectiveness and collaborate with engineering, product, design, and data teams to identify automation opportunities and drive adoption.

Develop and support scalable MES applications, reporting solutions, CI/CD pipelines, and event-driven integrations for global manufacturing operations. The role involves Java and SQL development, troubleshooting integrated systems, root-cause analysis, documentation, process improvement, and collaboration with engineering, DevOps, and manufacturing teams.

Analyze anti-bot and bot-mitigation systems, identify how websites detect and block scraping activity, and develop repeatable testing and bypass approaches. Build a greenfield agentic environment for evaluating anti-bot behavior, contribute to backend systems at scale, investigate complex incidents, and communicate findings clearly. The role requires deep web protocol knowledge, strong Node.js, TypeScript, and Python skills, scientific problem-solving, AI coding agent proficiency, and independent execution in a remote-first team.

Develop and maintain highly available, scalable API services for a global payments platform. Design and ship new products, improve platform performance, automate development processes, and deliver secure, testable, documented software. Collaborate with international technology teams and stakeholders while applying Agile practices, evaluating technologies, and supporting reliable 24/7 transaction processing.