Sr. .NET Developer

Client needs a hands-on .NET Developer who enjoys solving complex technical challenges, modernizing legacy applications, and building scalable solutions? We're seeking a talented developer to join a high-impact modernization initiative focused on upgrading critical enterprise applications and driving technology transformation.

This is an opportunity to work on a large-scale application modernization program, leveraging modern Microsoft technologies, cloud platforms, automation, and AI-assisted development tools.

You'll play a key role in upgrading and modernizing a portfolio of business-critical applications while helping shape the next generation of enterprise software solutions.

Responsibilities include:

Modernizing and enhancing existing .NET applications

Troubleshooting and resolving critical production issues and software defects

Developing new features using C#, ASP.NET MVC, and RESTful APIs

Designing scalable, maintainable, and secure software architectures

Integrating applications across multiple platforms and systems

Building modern user interfaces using HTML, JavaScript, and/or React

Designing and optimizing SQL and NoSQL data solutions

Identifying and remediating security vulnerabilities within applications

Supporting application deployments, releases, and production environments

Leveraging AI-assisted development tools to improve coding, testing, and delivery efficiency

Required Qualifications

Strong experience developing applications with:

C#

.NET Framework / .NET

ASP.NET MVC

REST API development

Experience diagnosing and resolving system issues, bugs, and production incidents

Solid understanding of software design patterns and application architecture

Experience with application integration and enterprise systems

Front-end development experience with HTML, JavaScript, or React

Hanks on working with SQL databases

Experience implementing security best practices within applications

Nice-to-Have Skills

Java and Spring Boot development experience

CI/CD, software packaging, and deployment automation

Cloud platform experience (AWS, Azure, or similar)

Automation experience that improved productivity, efficiency, or quality

Experience with GitHub Copilot, Amazon Q, or other AI-assisted development tools

GenAI certifications, training, or practical project experience

Experience supporting application modernization or migration initiatives

Why This Opportunity?

Work on a highly visible enterprise modernization effort

Exposure to the latest Microsoft technologies and development tools

Opportunity to influence architecture, automation, and engineering best practices

Collaborative environment that values innovation and continuous improvement

Strong potential for long-term career growth and conversion opportunities

If you're passionate about modernizing applications, solving challenging technical problems, and working with cutting-edge development technologies, we'd love to hear from you

Job Type & Location

This is a Contract position based out of Pasadena, CA.

Pay and Benefits

The pay range for this position is $65.00 - $80.00/hr.

Eligibility requirements apply to some benefits and may depend on your job classification and length of employment. Benefits are subject to change and may be subject to specific elections, plan, or program terms. If eligible, the benefits available for this temporary role may include the following: • Medical, dental & vision • Critical Illness, Accident, and Hospital • 401(k) Retirement Plan – Pre-tax and Roth post-tax contributions available • Life Insurance (Voluntary Life & AD&D for the employee and dependents) • Short and long-term disability • Health Spending Account (HSA) • Transportation benefits • Employee Assistance Program • Time Off/Leave (PTO, Vacation or Sick Leave)

Workplace Type

This is a hybrid position in Pasadena,CA.

Application Deadline

This position is anticipated to close on Jul 17, 2026.

About TEKsystems

We're partners in transformation. We help clients activate ideas and solutions to take advantage of a new world of opportunity. We are a team of 80,000 strong, working with over 6,000 clients, including 80% of the Fortune 500, across North America, Europe and Asia. As an industry leader in Full-Stack Technology Services, Talent Services, and real-world application, we work with progressive leaders to drive change. That's the power of true partnership. TEKsystems is an Allegis Group company.

The company is an equal opportunity employer and will consider all applications without regards to race, sex, age, color, religion, national origin, veteran status, disability, sexual orientation, gender identity, genetic information or any characteristic protected by law.

About TEKsystems and TEKsystems Global Services

We’re a leading provider of business and technology services. We accelerate business transformation for our customers. Our expertise in strategy, design, execution and operations unlocks business value through a range of solutions. We’re a team of 80,000 strong, working with over 6,000 customers, including 80% of the Fortune 500 across North America, Europe and Asia, who partner with us for our scale, full-stack capabilities and speed. We’re strategic thinkers, hands-on collaborators, helping customers capitalize on change and master the momentum of technology. We’re building tomorrow by delivering business outcomes and making positive impacts in our global communities. TEKsystems and TEKsystems Global Services are Allegis Group companies. Learn more at TEKsystems.com.

The company is an equal opportunity employer and will consider all applications without regard to race, sex, age, color, religion, national origin, veteran status, disability, sexual orientation, gender identity, genetic information or any characteristic protected by law.

San Francisco Fair Chance Ordinance: Pursuant to the San Francisco Fair Chance Ordinance, for all positions located in the city and county of San Francisco, we will consider for employment qualified applicants with arrest and conviction records.

Massachusetts Lie Detector: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.

Use of Artificial Intelligence (AI): We may use Artificial Intelligence (AI) to support parts of our hiring process, including sourcing, screening, and evaluating candidates. AI helps assess applications and qualifications, but final decisions are made by our hiring team. By applying, you acknowledge and agree that your application may be reviewed using AI tools.