Freelance Full Stack Web Developer Jobs in Katy, TX

About AOI
Applied Optoelectronics, Inc. (AOI) is a leading developer and manufacturer of advanced optical and HFC networking products — the building blocks that power AI datacenters, CATV broadband, telecom, and fiber access networks around the world. Headquartered in Sugar Land, Texas, AOI is a vertically integrated company that designs and manufactures everything from semiconductor laser chips to finished optical transceivers, serving tier-one customers across cloud computing, broadband, and telecom. With R&D operations in Atlanta, GA and global manufacturing presence in Taiwan and China, AOI is publicly traded on the Nasdaq (AAOI) and is actively expanding its U.S.-based manufacturing operations in Sugar Land to meet accelerating demand in the AI datacenter market.

Summary
We are seeking a Full Stack Software Engineer to design, build, and own the internal software systems that power our manufacturing operations. This is a high-autonomy role spanning the entire stack; from front-end dashboards and back-end services to equipment-level communication protocols — where you will drive architecture decisions and deliver end-to-end solutions across MES/RMS integrations, production monitoring tools, and SECS/GEM host software. The ideal candidate pairs strong C#/.NET fundamentals with the initiative to define systems in a growing environment, not just maintain them.
You will join a team of approximately ten engineers within the MIS department, working alongside MES, database, and systems engineering colleagues in an open office environment with occasional time in cleanroom manufacturing areas. As AOI scales U.S. production capacity to meet accelerating AI datacenter demand, this role will be central to building the software infrastructure that supports higher throughput, better yield and yield visibility, with more reliable equipment automation.
Job Responsibilities
Internal Web Application Development

• Design, develop, own, and maintain full-stack web applications for internal manufacturing operations, including production dashboards, equipment monitoring portals, and operational tools.
• Build responsive front-end interfaces and robust back-end services using C# / .NET (ASP.NET Core, Blazor) as the primary stack, with JavaScript/TypeScript as a secondary development stack.
• Implement scalable and maintainable software architectures that serve multiple teams across manufacturing, process engineering, quality, and operations.
• Write clean, efficient, and well-documented code that adheres to best practices and coding standards.

Equipment Automation & SECS/GEM

• Maintain and enhance EAP (Equipment Automation Program) software that enables communication between manufacturing equipment and factory systems.
• Configure and maintain SECS/GEM communication in compliance with SEMI standards (e.g., SECS-I, HSMS, GEM), including equipment messaging, event reporting, alarms, status variables, and remote command execution.
• Support equipment qualification and acceptance testing using SECS/GEM requirements

System Integration

• Integrate manufacturing tools with:
  • MES (Manufacturing Execution System) for lot tracking and production control
  • RMS (Recipe Management System) for recipe download, validation, and version control
• Collaborate with cross-functional teams (Process Engineering, Manufacturing, IT, Quality) to ensure seamless system interoperability.

Data Collection, Analysis & Dashboards

• Build and maintain web-based dashboards for:
  • Production performance monitoring and yield analysis
  • Equipment health and downtime tracking
• Utilize SQL databases to store, query, and analyze production and equipment data.
• Work with business stakeholders to best design, implement, and maintain data-driven visualizations

Troubleshooting & Production Support

• Diagnose and resolve complex equipment automation, communication, and data integrity issues in a high-volume manufacturing environment.
• Provide support during production issues related to automation systems as needed.
• Work directly with equipment vendors to resolve interface or protocol issues.

Documentation & Continuous Improvement

• Develop and maintain software design documents, interface control documents (ICDs), and operational procedures.
• Ensure systems comply with internal controls, quality standards, and audit requirements.
• Identify automation opportunities to improve throughput, reduce manual intervention, and enhance equipment utilization.
• Stay current on emerging technologies and propose system enhancements aligned with AOI’s manufacturing roadmap.

Qualifications

Candidates must be authorized to work in the United States. Visa sponsorship is not available for this position.

Required:

• Bachelor’s or Master’s degree in Computer Science, Electrical Engineering, Automation Engineering, or a related STEM discipline, or equivalent professional experience.
• 3–5 years of professional software engineering experience.
• Strong proficiency in C# / .NET development (ASP.NET Core, Blazor, Entity Framework, or similar frameworks).
• Solid experience with SQL databases (queries, joins, stored procedures, performance tuning).
• Exposure and experience with front-end technologies (HTML, CSS, JavaScript/TypeScript) and modern web frameworks.
• Experience with RESTful API design and back-end service development.
• Proficiency with version control (Git) and collaborative development workflows.
• Strong problem-solving, debugging, and communication skills.

Preferred:

• Working knowledge of EAP systems, SECS/GEM protocols, and SEMI standards.
• Experience with MES (Manufacturing Execution Systems) integration in semiconductor, optoelectronics, or high-volume electronics manufacturing environments.
• Experience with Python and/or LabVIEW.
• Familiarity with cloud services (Azure, AWS, GCP) and CI/CD pipelines.
• Mandarin language proficiency is a plus.

Location & Work Environment

This position is full-time and based in Sugar Land, Texas. This location has a combination of office, warehouse, and cleanroom manufacturing work environments.

• Business Hours for this position are 9am to 6pm CT, Monday through Friday.
• This position may require occasional after-hours response for critical facility issues, site inspections, or executive events.

Why AOI?

In addition to competitive salary, AOI offers:

• Flexible and competitive health (medical, dental, vision) plans offer the employee with the right options to meet individual and family needs
• Employer matching on 401(k) deferrals
• Generous PTO policy, with unused PTO payout at end of the year
• Relocation packages available within the United States.

Applied Optoelectronics, Inc (AOI) is committed to providing equal opportunity in all of our employment practices, including hiring, placement, promotion, training, transfer and compensation, to all qualified applicants and employees without regard to race, color, national origin, citizenship, religion, sex, veteran status, age, disability, marital status, or any other category protected by State or U.S. Federal law. Moreover, we endeavor to treat our employees fairly.

We do not accept unsolicited proposals from third-party recruiters or agencies. Contacting hiring managers directly may result in disqualification of submissions.