Top Software Engineer Jobs in Barcelona

Design, implement, and own end-to-end backend features in a Python-based, event-driven platform. Improve architecture for performance, reliability, and scalability, participate in design reviews, mentor peers, ensure CI/CD and testing best practices, and collaborate with Product and Data teams to deliver production-ready services.

Build and maintain Finance & Compliance services to calculate revenue, invoice partners and customers, automate tax reporting, and ensure scalable, reliable transaction processing. Design end-to-end features, participate in architecture, improve observability and performance, and mentor teammates while owning core components.

Lead the design and development of scalable backend APIs and services focusing on IBM Cloud, providing technical leadership and collaborating with cross-functional teams.

The Senior Software Engineer will collaborate in small teams to develop and maintain backend and frontend components, focusing on high-availability systems, writing tests, and continuous delivery on Google Cloud Platform.

Design, implement, test, and maintain cloud-first web applications. Build secure, maintainable code using event-driven architecture and cloud services (AWS/Azure). Collaborate with cross-functional teams, mentor junior engineers, and support CI/CD and PWA development.

The Senior Software Engineer will develop core business products, ensuring performance and scalability, and automate development processes while collaborating with stakeholders.

Design, build, and harden Chromium-based browser components in C++ to power Menlo's AI/agent initiatives; apply networking and HTTP security expertise; integrate AI agents and MCP servers; build tooling in Python or Rust; deploy and operate cloud infrastructure (AWS/GCP, Kubernetes, Terraform); debug and optimize performance-critical systems; collaborate cross-functionally.

Design, build, and operate Threat Protection and ShadowAI services: scalable distributed systems and APIs that detect and control risky web and generative AI usage. Own features end-to-end, maintain availability and latency SLOs, write tests, perform code reviews, use AI-assisted tools, and collaborate with cross-functional teams to improve detection accuracy and production reliability.

Lead architecture and technical direction for enterprise SaaS microservices. Contribute hands-on to critical code, design scalable distributed systems, ensure reliability and security, mentor engineers, and collaborate cross-functionally to align technical solutions with business goals.

Build and own backend integrations connecting Voxie's SMS platform to CRMs, POS, marketing tools, and messaging providers. Design scalable, testable serverless systems on AWS, handle high-throughput messaging, implement reliable API/webhook/SFTP/batch pipelines, and collaborate with sales, partners, and customers to scope and deliver integrations.

Provide organisation-wide technical leadership as a Staff Software Engineer: shape technical strategy, design scalable distributed systems, set engineering standards, mentor senior engineers, improve reliability/observability/CI-CD, and contribute hands-on to critical cloud-native payment systems.

Lead and own platform architecture across Infrahub ecosystem, implement high-impact architectural improvements, reduce technical debt, champion AI-first engineering, provide hands-on technical leadership, mentor engineers, and collaborate with product and leadership to ensure scalable, extensible systems.

Develop cloud-native production systems that process large data volumes. Engage in backend development with Rust and frontend with Angular. Collaborate on product development.

As a Senior Software Engineer, you'll design and build scalable market data systems, improve API architecture, and enhance overall system performance, contributing to Alpaca's infrastructure for trading financial assets.

Build and maintain core post-trade clearing systems and securities-finance infrastructure. Own projects end-to-end, design reliable distributed services and RESTful APIs, integrate new clearing partners, participate in on-call rotation, and improve systems to enable new product offerings.

Lead the development of software solutions for a logistics platform, overseeing technical strategy, mentoring teams, and ensuring high-quality software delivery.

Build and own end-to-end features across Sona’s platform using AI-assisted development. Direct and correct agent-produced code, work cross-functionally, engage customers in discovery and workshops, and contribute across scheduling, payroll, HR, and mobile domains.

As a Mid-Senior Software Engineer at Smadex, you will design and implement features, ensure code quality, and maintain system performance in a collaborative environment.

Build and maintain scalable landing experience apps and services using modern web stacks. Design and implement high-quality solutions, drive technical design, troubleshoot performance and stability issues, mentor junior engineers, collaborate with product and design, improve development processes, and maintain documentation. Participate in on-call rotations and hybrid office collaboration.

Design, build, operate, and support resilient distributed platform services. Write maintainable code, troubleshoot production issues, improve reliability and observability, and assist internal teams. Participate in on-call rotations and collaborate on platform evolution.

Lead design and delivery of scalable, secure cloud-native backend services, shape platform architecture, mentor engineers, contribute hands-on (Go/C++ backends, React frontends), establish engineering standards, improve observability and reliability, and collaborate with product and architecture teams to align technical investments.

Design, build, and operate distributed, high-volume transactional backend services in Go. Own scope, architecture, correctness guarantees, production behavior, observability, and automated verification. Collaborate across product, infra, and QA while using agent-driven engineering practices.

Build and maintain customer-facing growth features, instrumentation, and experimentation platforms. Partner with Product, Design, and Data to design and analyze A/B tests, ship reliable event pipelines, improve performance and scalability, mentor engineers, and shape technical strategy to drive acquisition, activation, engagement, retention, and monetization.

Lead end-to-end partner integrations: design and implement auth/identity flows, multi-tenancy, data movement, and production systems. Own infrastructure, CI/CD, deployments, observability and on-call. Collaborate with internal teams, work across external platforms, write design docs and set technical direction for a growing team.

Lead and be hands-on in architecture and shipping code to scale AI-powered mobile apps from 0->1 and 1->100. Own complex technical challenges, improve performance and reliability for millions of users, migrate critical infrastructure, raise engineering standards, and collaborate cross-functionally with product and design.