C# Developer (POS Applications)

TEKsystems; Bethesda (MD); Hybrid; USD 75,768 - 103,320; Full time

Benefits offered by this job

Medical, dental & vision

401(k)

Life insurance

Disability insurance

Health Spending Account

Transportation benefits

Employee Assistance Program

Time Off/Leave (PTO)

Job summary

TEKsystems in Bethesda, MD is seeking a C# Developer to design, build, and optimize custom client-side applications that run inside Oracle MICROS Simphony POS environments. The role emphasizes high-performance edge software with offline-first data, local storage, real-time processing, and resilient transaction workflows.

Collaborate to extend POS functionality, use SQLite/SQL Server Express for local data, and enable RabbitMQ messaging for reliable distributed operation.

Qualifications

• 4+ years of professional experience with C#/.NET Core.
• Experience building desktop/client-side applications and plugins.
• Strong OO design and lifecycle management.
• Experience with lightweight relational databases (SQLite or SQL Server Express).
• Experience designing schemas and local data storage.
• Experience with RabbitMQ or similar messaging technologies.
• Knowledge of threading, concurrency, and distributed app design.
• Experience building resilient apps for intermittent connectivity.

Responsibilities

• Design and develop custom applications and extensions that run directly within POS terminal environments.
• Build high-performance client-side solutions that support transaction processing, order management, and operational workflows.
• Develop and maintain local data storage using SQLite or SQL Server Express.
• Implement reliable messaging and event-driven communication using RabbitMQ.
• Support offline-first architectures, local synchronization, and resilient transactions.
• Optimize performance, scalability, and reliability across distributed workstation environments.
• Troubleshoot complex issues related to performance, data sync, and system integrations.
• Collaborate with engineering teams to extend POS functionality and support evolving requirements.
• Participate in testing, deployment, monitoring, and maintenance activities.

Skills

C#/.NET Core

Desktop applications

Threading/concurrency

Offline-first

Distributed systems design

RabbitMQ

Tools

SQLite

SQL Server Express

Job description

*C# Developer (POS Applications)* *Location:* Bethesda, MD

*Work Environment:* Hybrid - 4 days onsite, 1 day remote

*Experience Level:* Mid-Level

*Employment Type:* Contract

Position Overview

We are seeking a *C# Developer* to design, build, maintain, and optimize custom client-side applications that run directly within an Oracle MICROS Simphony POS environment. This position focuses on developing high-performance edge applications that operate at the workstation level, supporting local data storage, real-time event processing, custom transaction workflows, and offline-first functionality.

The ideal candidate will have strong experience in *C#/.NET Core*, lightweight relational databases, enterprise messaging systems, and distributed application design. This role offers the opportunity to work on complex POS solutions that extend platform functionality beyond out-of-the-box capabilities in high-volume environments.

Key Responsibilities

• * Design and develop custom applications and extensions that run directly within POS terminal environments.
• * Build high-performance client-side solutions that support transaction processing, order management, and operational workflows.
• * Develop and maintain local data storage solutions using *SQLite*, *SQL Server Express*, or similar lightweight relational databases.
• * Implement reliable messaging and event-driven communication using *RabbitMQ* or equivalent message brokers.
• * Support offline-first architectures, local synchronization, and resilient transaction processing.
• * Optimize application performance, scalability, and reliability across distributed workstation environments.
• * Troubleshoot complex issues related to application performance, data synchronization, and system integrations.
• * Collaborate with engineering teams to extend POS functionality and support evolving business requirements.
• * Participate in application testing, deployment, monitoring, and maintenance activities.

Required Qualifications

• * 4+ years of professional experience developing applications using *C#/.NET Core*.
• * Experience building desktop applications, client-side software, plugins, extensions, or class libraries.
• * Strong understanding of software architecture, object-oriented design, and application lifecycle management.
• * Hands-on experience with lightweight relational databases such as *SQLite* or *SQL Server Express*.
• * Experience designing schemas, writing optimized queries, and managing local data storage.
• * Practical experience with *RabbitMQ* or similar enterprise messaging technologies.
• * Strong knowledge of threading, concurrency, synchronization, and distributed application design.
• * Experience building resilient applications that function effectively in intermittent connectivity environments.

Preferred Qualifications

• * Experience working with *Oracle MICROS Simphony* or other enterprise POS systems.
• * Experience migrating legacy integrations from SOAP/XML-based architectures to REST/JSON services.
• * Experience working with cloud-based platforms and Microsoft Azure technologies.
• * Familiarity with transaction processing systems, payment workflows, and retail, hospitality, or restaurant technology environments.

What You'll Work On

This role supports the ongoing evolution of a custom POS extension platform designed to enhance and extend standard POS capabilities. You'll help build scalable, production-ready applications that support transaction processing, local data management, and operational workflows at the edge.

The solutions developed in this role directly contribute to maintaining fast, reliable, and adaptable POS experiences in high-volume, distributed environments where performance and uptime are critical.

Interview Process

• * Initial 15-minute virtual screening with a member of the hiring team
• * Technical evaluation
• * Onsite 1-hour discussion with stakeholders

Work Environment

* Hybrid schedule based in Bethesda, MD

* 4 days onsite and 1 day remote

* Collaborative team focused on POS innovation, distributed systems, and enterprise-scale application development

Why This Opportunity?

This is an excellent opportunity for a developer who enjoys solving complex technical challenges, working close to the edge where transactions happen, and building highly reliable software without a predefined blueprint. You'll have the chance to influence the direction of a growing platform while gaining specialized experience in POS client architecture, distributed transaction systems, and enterprise application scalability.

*Job Type & Location*This is a Contract position based out of Bethesda, MD.

*Pay and Benefits*The pay range for this position is $55.00 - $75.00/hr.

Benefits

• * 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 Bethesda,MD.

*Application Deadline*This position is anticipated to close on Aug 8, 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 are a team of 80,000 strong, working with over 6,000 customers, including 80% of the Fortune 500 across North America, Europe, 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.