Top Software Engineer Jobs in Spain

The Software Developer will build scalable web applications, collaborate with full-stack engineering teams in an Agile environment, solve complex customer problems, review peer code, and contribute to cross-team projects. The role requires software development experience, database optimization knowledge, strong communication, adaptability to new technologies, and mentorship experience. It is based in Barcelona with hybrid office attendance expected at least twice weekly.

Develop and validate battery diagnostic algorithms, battery models, and BMS architectures for advanced energy storage systems. Lead or support international projects, customer technical discussions, characterization and validation testing, and test-data analysis. Supervise junior engineers and interns while collaborating with international teams. The role focuses on battery state detection, modeling, simulation, and AI-based algorithms using MATLAB and Simulink, with C and Python as valuable additional skills.

Design and build Go services for Telnyx’s serverless platform, function deployment pipeline, global control plane, and edge infrastructure. Own backend APIs, resource lifecycles, workload deployment, asynchronous workflows, observability, and reliability. Work with Kubernetes, distributed systems, relational databases, and multi-region services. Improve developer experience through APIs, CLI tooling, and clear error handling, while participating in on-call and diagnosing production performance and reliability issues.

Develop backend software for Arista’s CloudVision distributed network management platform. Design architectures, implement scalable services and network analytics applications, write automated tests, and deploy projects through continuous delivery pipelines. Collaborate with product management, customers, and project teams to define requirements and deliver production-ready solutions. Work with technologies including Go, C++, distributed systems, Kubernetes, Kafka, HBase, ClickHouse, Elasticsearch, and Zookeeper.

Software Engineering Intern supporting mobile game development in Unity. Responsibilities include helping build gameplay features, internal tools, and workflow improvements; testing, debugging, optimizing, and polishing gameplay; participating in code reviews; collaborating with designers and artists; proposing technical solutions; and documenting work. The role requires familiarity with Unity, C#, graphics, computer mathematics, and mobile platforms, plus enrollment in a relevant degree program.

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.

The Software Developer will design and develop web applications, improve system reliability, and collaborate on architecture and deployment strategies.

Develop and maintain highly available, secure, scalable API services for a global payments platform. Design and ship new products, improve platform performance, automate development processes, participate in Agile practices, and collaborate with global technology teams. The role requires strong Golang development skills, event-driven architecture experience, relational database knowledge, and familiarity with web and API solutions.

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.

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 and scale an AI-powered translation and localization platform using Java and Spring Boot. Develop REST APIs, microservices, and Kafka-driven pipelines; integrate LLMs and machine translation providers; optimize quality, scalability, latency, and cost; and support monitoring, testing, deployments, and production troubleshooting. Collaborate with engineering, product, and business stakeholders to expand multilingual content capabilities.

Build and improve reliable, user-focused product experiences across the frontend and backend. Partner with Product, Design, and Engineering to understand user needs, propose solutions, implement features, troubleshoot software, write documentation, and contribute to technical and product decisions. Develop tested JavaScript or TypeScript code using React, Node.js, and related technologies while continuously learning and taking ownership of increasingly complex problems.

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.

Build and improve frontend platform capabilities, developer tooling, Golden Paths, CI/CD, deployment workflows, and application architecture. Improve frontend delivery, performance, caching, observability, testing, and developer experience across the stack. Operate production systems, participate in incident response and technical discussions, establish practical standards, and collaborate with product engineers, platform teams, and technical leaders.

Build scalable, maintainable frontend applications using React, JavaScript, and Next.js. Develop reusable component libraries and design systems with Storybook and CSS-in-JS, ensuring WCAG 2.1 AA accessibility. Write clean, tested, documented code; optimize performance and cross-browser behavior; and collaborate with Product, Design, Backend, clients, and stakeholders. Work in Agile environments and use AI tooling to improve development workflows.

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.

Develop and maintain AI-powered web products and platforms using React, Next.js, Node.js, GraphQL, and related technologies. Responsibilities include writing clean, tested, documented code; making architecture and technology-stack decisions; adapting across varied stacks; collaborating with clients and teams; applying web standards, accessibility, and optimization practices; and using AI tools to improve workflows.

As a Senior Product Software Engineer, you will design, develop, and maintain software applications, collaborate with teams, optimize performance, and provide technical support.

Lead backend engineering for digital-asset integrations, building secure, scalable microservices on Kubernetes. Design event-driven architectures, integrate trading and custody systems, ensure regulatory controls, own delivery from estimation to production, write comprehensive tests, and collaborate with Product, Compliance, Risk, and Operations.

Build and operate production custody systems: signing service, key management, chain integrations, and transaction pipelines. Own end-to-end subsystems, integrate new chains, collaborate with cryptography on threshold signing and key recovery, write post-mortems, and produce clear async design docs and PRs.

The Senior Software Engineer will design and implement systems for AI integration, build scalable backend services, and mentor team members, ensuring high-quality systems that meet user needs.

Build AI-powered automation agents and modernize legacy enterprise systems for SME clients. Responsibilities include developing Python backends, integrating Salesforce, SAP, and Microsoft Dynamics, cleaning and transforming messy data, and delivering outputs through Power BI, PDFs, and APIs. The role involves working with LLMs, agent frameworks, and AI coding tools while collaborating with Spanish- and English-speaking clients in a fully remote consultancy environment.

Build and scale backend systems for AI-native construction procurement software. Own data models, GraphQL APIs, distributed processing semantics, integrations with construction ERPs, authorization, approvals, and transactional business workflows. Develop in Go with Postgres and AWS, while contributing to AI-driven document extraction, optimization, observability, and complex integrations. Collaborate in a fast-moving startup environment with evolving product requirements and strong ownership expectations.