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Senior Backend Engineer - Real-Time Health Data
Syntrace (via its Lingo digital health platform) is hiring a Senior Backend Engineer in Barcelona to design scalable, secure, resilient backend systems for real-time biosensor data analytics, leading high-performance APIs, event-driven services, and data integrations alongside Product, Mobile, SRE, and Data/ML teams.
Senior Backend Engineer - Real-Time Biosensor Data
Senior Backend Engineer at Hedon Technologies (Lingo digital health platform) designing, implementing, and optimizing scalable microservices and APIs that process real-time biosensor data to deliver live health insights, while collaborating with Product, Mobile, SRE, and Data/ML teams in a HIPAA/GDPR-compliant environment.
Backend Developer / Tech Lead | Node.js, NestJS y Microservicios
Technical Business Analyst with a backend development background (Node.js, TypeScript, NestJS, microservices) working on a stable project for a leading international company in Barcelona: gathering requirements, proposing technical solutions, building the technical backlog, documenting APIs, and unblocking the delivery team.
Azure Backend Engineer - Cloud Native & AI-Assisted Development
Backend engineer (Madrid) building cloud-native APIs, microservices and integrations on Azure (.NET/C#, Azure Functions, AKS, Service Bus, Logic Apps, Key Vault), using AI coding assistants like GitHub Copilot and Claude Code as a routine part of the development cycle.
Junior Backend Go Developer
Junior backend developer in Madrid building and maintaining scalable Go microservices and RESTful APIs, integrating services with other teams, debugging production issues, writing tests, and joining Agile sprint planning, with mentorship from senior engineers.
Backend Developer | Driving Innovation In Cybersecurity
Backend developer at Orbik (part of the Mondragon cooperative ecosystem) building RESTful APIs and microservices for cybersecurity of industrial products in the Basque Country. Day to day: full API lifecycle development, performance optimization, code reviews, and CI/CD with GitLab.
Remote.NET Backend Developer — Flexible Hours + Perks
Backend developer at ALTECH in Barcelona building applications with .NET Framework or .NET Core, working with multidisciplinary teams to define requirements. The role values 2-5 years of experience, SQL/NoSQL knowledge and Scrum, with flexible hours and the option to telework.
Senior BackEnd Developer & Team Leader
Senior back-end developer & team lead at WonderBits in Valencia (hybrid, 2 office days/week): plans and builds innovation and client projects with .NET/C#, TypeScript/Node.js (plus Python), using DDD/CQRS/TDD, Docker and CI/CD while helping lead a 22-person tech team. Permanent contract paying €35-45/hour.
Backend Developer (Kotlin/Spring Boot)
Builds robust, maintainable backend services in Kotlin and Spring Boot: designs REST APIs (Swagger/OpenAPI), persists data in SQL/DynamoDB, integrates Amazon SQS messaging, and applies TDD with hexagonal and event-driven architectures — working in a 100% remote Scrum/Scrumban team with CI/CD and observability practices.
Senior.NET Backend Developer
Senior .NET backend developer based in A Coruña (hybrid) developing and evolving C#/.NET services for an international company's own product, including modernizing legacy components to modern .NET. Day to day covers event-driven microservices, SQL Server data access, REST APIs, code reviews, and production incident handling.
Senior.NET Backend Developer
Senior .NET Backend Developer in A Coruña (hybrid) at tech boutique 3MT Global Services, building and maintaining C#/.NET services for an international client's own product and modernizing legacy components to modern .NET. Day-to-day: functional analysis, technical design, end-to-end delivery, code reviews and production support.
Backend Developer (C.NET)
Backend Developer in SKIDATA's Madrid team building custom C#/.NET integrations that connect third-party systems with SKIDATA's access-solution products, using REST, SOAP, gRPC, RMQ and sockets. Owns projects from design through delivery, supports partners and regional colleagues; hybrid work, English and Spanish required.
PHP Backend Developer
PHP Backend Developer at Tappx, an AdTech firm, designing and maintaining scalable SSP (supply-side platform) systems and internal PHP tools through their full lifecycle, from design to deployment and monitoring. Core stack is PHP and MySQL, with Redis/Aerospike, CI/CD, and AI tooling to boost productivity.
Backend Developer - International Project
Though titled 'Backend Developer', the description is for a fully remote Project Manager driving international market-expansion projects for a fast-growing e-commerce client: market research, budgets, cross-functional coordination, and launches (initially the Canary Islands), using PM tools like Asana and Jira.
Desarrollador Backend Java - Microservicios Sector Público
Senior backend developer designing, building and optimizing scalable RESTful APIs and web services with Python and Django (relational/non-relational DBs, cloud), working fully remotely from Madrid. Note: the title references Java microservices for the public sector, while the description's stack and requirements are Python/Django.
Senior backend dev
Hasten Group is hiring a mid-senior, full-time developer in Madrid (on-site). The title says senior backend, but the body describes building web applications and integrating APIs; the required skills (Spark, Scala, PySpark, Hadoop, Hive, Impala, AWS) point toward big-data engineering.
Desarrollador/A Backend Senior
Senior backend developer at Grupo SaveFamily, a maker of family-safety smartwatches, designing and maintaining Node.js APIs and services on PostgreSQL, integrating RabbitMQ messaging, writing unit/integration tests, and collaborating in agile teams, with AWS/Docker/Jenkins CI-CD as a plus.
Desarrollador Backend - Full Presencial en Gorbernador Crespo (Santa Fe)
Nos encontramos en la búsqueda de Desarrollador Backend con conocimientos en IA para importante empresa industrial de Santa Fe. 📍 Modalidad 100% presencial en Gobernador Crespo (provincia de Santa Fe) 🕘 Horario: de…