C# Developer (POS Applications)

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

1. Initial 15-minute virtual screening with a member of the hiring team
2. Technical evaluation
3. 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.

Eligibility requirements apply to some benefits and may depend on your jobclassification and length of employment. Benefits are subject to change and may besubject to specific elections, plan, or program terms. If eligible, the benefitsavailable 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 Bethesda,MD.

Application Deadline

This position is anticipated to close on Aug 8, 2026.

About TEKsystems

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.

About TEKsystems and TEKsystems Global Services

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.