Flexcompute is leading the transformation of engineering simulation with our revolutionary ultra-fast simulation technology. Our flagship products, including the industry-leading Computational Fluid Dynamics (CFD) software Flow360 and electromagnetic simulation software Tidy3D, are reshaping how simulations are conducted across diverse sectors. Founded by visionaries from Stanford and MIT and supported by top-tier venture capital firms, we are a rapidly growing team dedicated to breaking boundaries and challenging the norms of the multi-billion-dollar engineering simulation market.
We are looking for a Senior Backend Software Engineer to help us design and implement scalable solutions that meet the growing demands of our advanced EM simulation platform.
Additionally, the candidate will help us enhance our data management, frontend-backend API unification, and cloud integration.
Contribute to general software development efforts, such as API unification, simulation data management (e.g., Collaborate with EM and infrastructure teams to implement simulation-specific solutions, including enhancements to back-end/scheduler integrations and Python front-end functionality.
Improve our task pipelines through an innovative design for a web API in a multi-physical simulation context.
Develop and maintain hybrid cloud compute and storage solutions, integrating on-premise HPC systems with modern cloud platforms.
Optimize and manage high-performance computing clusters equipped with high-speed interconnects
This is a senior seat. We keep the team small and senior on purpose, so you will own real pieces of the platform end to end, with little direction and direct access to the founders.
Strong backend engineering in at least one of Java, Python or C++. Real production cloud experience, AWS preferred.
Direct ownership of a production backend service,



from design through deployment and operation.
Fluent professional English, spoken and written.
Based in Spain, with the right to work there without visa sponsorship, and available on Spanish working hours with about six hours of overlap with our Boston team.
A bachelor's degree in computer science, computer engineering, telecommunications engineering or a closely related field.
Kubernetes and Docker, Terraform or Ansible, monitoring and observability tooling, Linux troubleshooting, networking and security practices, our simulation stack, and HPC (preferred, not mandatory). We look for people who have entered a new domain before, learned it fast and reached ownership.
Load balancing, autoscaling, and queues or streaming systems such as SQS, SNS or Kafka.
Experience integrating cloud platforms with HPC environments or large compute clusters.
Familiarity with job schedulers or batch systems, distributed compute frameworks, or large-scale data pipelines.
A degree in computer science, computer or telecommunications engineering, mathematics, physics or a related field from a leading university. Example Projects
Architect and deploy infrastructure that runs distributed simulation workloads across cloud and on-premise compute
Design and implement scalable web APIs for simulation job orchestration and data access
Build CI/CD pipelines and infrastructure-as-code systems for reproducible deployments
Develop hybrid cloud solutions connecting on-prem HPC clusters with AWS compute and storage
Implement monitoring and observability systems to track simulation performance and reliability
No online assessment. Remote within Spain, on Spanish working hours with about six hours of overlap with our Boston team.
Fully adaptable hours and unlimited PTO.
Learning sponsorship, a travel allowance, an AI tools budget (we pay for Claude, Cursor and similar) and a fitness benefit.

📌 Senior Backend Software Engineer (Remote) (Madrid)
🏢 Flexcompute
📍 Madrid