Castelion
Senior Web Developer
Allen, TX +3 · Senior · Full-time · Posted Oct 20, 2026
- Location
- Allen, TX
Torrance, CA
716 South Greenville, Suite 160, Allen, TX 75002
19951 Mariner Ave, Torance, CA 90503 - Visa sponsorship
- Employment is contingent upon the candidate’s ability to access applicable export-controlled information without additional export licensing. If the role requires a security clearance or other government authorization, the candidate may need to meet applicable citizenship or other eligibility requirements.
About the job
Leads hands-on development and production readiness of an internal web application that unifies engineering tools and supports data-intensive workflows and hardware manufacturing.
What you'll do
- Own the application architecture, implementation, deployment, reliability, and performance for large-scale data workflows.
- Unify calibration, field testing, ML annotation and training, and Foxglove tools into a user-focused product.
- Set technical priorities, work directly with users, and mentor junior developers while contributing to development.
What they ask for
- Experience leading a web application from architecture and implementation through production deployment.
- Strong proficiency in Python, FastAPI, and asynchronous programming with asyncio.
- Experience with PostgreSQL, ORM, blob or object storage, and a modern frontend framework with JavaScript or TypeScript, HTML, and CSS.
- Experience designing responsive applications for large datasets and building reliable applications with automated testing, CI/CD, monitoring, and safe deployment and rollback strategies.
Nice to have
- Experience with Plotly or similar data visualization libraries.
- Experience building internal engineering tools, scientific applications, or data-intensive web platforms.
Tools
Python, FastAPI, asyncio, PostgreSQL, JavaScript, TypeScript, HTML, CSS
AI focus
The application includes workflows for ML annotation and training; no AI model development work is stated.
Model-written summary · the original posting is authoritative