About Castelion
Castelion is bringing a new approach to defense development and production: one that focuses on short, iterative design cycles, rapid testing in development, and modern commercial manufacturing strategies for production at scale. We're designing, building, and testing next generation long range strike weapons systems to give America and its Allies a definitive edge and deter future conflicts.
Senior Software Engineer - Data Infrastructure
Were looking for a hands-on software architect who can design and build Castelion's mission data infrastructure from the ground up. Our hardware generates terabytes of telemetry and test data across manufacturing, lab, and flight environments. You will be the first engineer to architect this company-wide system, from ingestion through visualization, ensuring our hardware teams, technicians, and analysts can get the right data at the right time. This role is not about wiring together existing cloud tools, its about inventing the architecture, designing core services, and implementing the systems that will define how Castelion handles data for years to come.
Responsibilities
- Architect and implement scalable systems for real-time and batch ingestion of telemetry, test, and manufacturing data from heterogeneous sources.
- Design and build APIs, storage models, and query systems for continuous time series data with rich metadata.
- Implement data access and visualization layers for non-software users (engineers, analysts, technicians).
- Define performance, reliability, and scalability requirements - and meet them with clean, maintainable code.
- Establish coding standards and software development best practices for infrastructure engineering at Castelion.
Basic Qualifications
- 5+ years designing and coding large-scale distributed systems, back-end services, or real-time data platforms in a production environment.
- Strong programming ability in Python, C++, or similar system languages, with fluency in algorithms, data structures, and concurrency.
- Experience designing data storage and retrieval systems (PostgreSQL, time series DBs, OLAP engines, custom storage layers).
- Deep understanding of data ingestion from multiple protocols (message queues, streaming telemetry, APIs, file drops).
- Hands-on experience with query optimization, data modeling, indexing, and performance profiling.
- Strong Linux background and experience deploying services in cloud environments (Azure/AWS).
- Demonstrated ability to take a system from concept architecture implementation production.
Bonus Points
- Experience building internal tools or platforms for hardware, manufacturing, or scientific data.
- Knowledge of telemetry data formats, time series analysis, or scientific computing.
- Exposure to real-time visualization frameworks (Foxglove, Grafana, custom UIs).
Leadership Qualities
- Bias to Action and Creative Problem Solving. Desire and experience questioning assumptions in ways that lead to break through ideas that are ultimately implemented. Successfully bring in applicable processes/concepts/materials from other industries to achieve efficiency gains. Ability to personally resolve minor issues in development without requiring significant support.
- High Commitment, High Initiative. A successful candidate will have a genuine passion for Castelion's mission and consistently look for ways to contribute to the company's technical goals and prevent hardware blockers. Ability to work in a fast paced, autonomously driven, and demanding atmosphere. Strong sense of accountability and integrity.
- Clear Communicator. Proactively communicates blockers. Trusted in previous roles to be voice of company with regulators, suppliers, gate keepers and customers. Capable of tactfully managing relationships with stakeholders to achieve company-desired outcomes without compromising relationships. Emails, IMs and verbal interactions are logical, drive clarity, and detailed enough to eliminate ambiguity.
ITAR Requirements
- To conform to U.S. Government export regulations, applicant must be a (i) U.S. citizen or national, (ii) U.S. lawful, permanent resident (aka green card holder), (iii) Refugee under 8 U.S.C. § 1157, or (iv) Asylee under 8 U.S.C. § 1158, or be eligible to obtain the required authorizations from the U.S. Department of State.
Employment with Castelion is governed on the basis of competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.
All employees are granted long-term stock incentives as part of their employment at Castelion. All employees receive access to comprehensive medical, vision, and dental insurance, and the company offers four weeks of paid time off per year.
