Senior Software Engineer/Technical Lead

About The One 23 Group

At The One 23 Group (O23G), our mission is to set the benchmark for excellence in government services. We empower customers across the Department of War, Intelligence Community, Homeland Security, and Federal Civilian agencies through innovative technology solutions that strengthen national security and mission success.

Our expertise spans Operational Intelligence, Secure Digital Engineering, Infrastructure Engineering, Cybersecurity, Cloud Modernization, Data Analytics, and Artificial Intelligence. As a rapidly growing middle-market federal contractor, we combine the agility of an innovative technology company with the operational maturity and execution capabilities of a trusted government partner.

We invest in our people, foster a culture of innovation, and deliver mission-focused solutions that solve our customers' most complex operational challenges.

Position Overview

The One 23 Group is seeking a hands-on Software Engineer/Technical Lead to drive the growth of our Digital Twin and Modeling & Simulation capabilities across federal agencies.

Our in-house simulation platform combines a C# engine for discrete event and agent-based models with a Unity based user interface and 3D environment. It supports high visibility port of entry operations for a Homeland Security customer.

This position is ideal for an experienced technical leader who enjoys solving complex customer challenges, mentoring engineering teams, and delivering innovative solutions within mission-critical environments.

Key Responsibilities

Simulation and 3D Integration

• Own the technical architecture that brings our discrete event and agent based engines together with the Unity 3D environment into one coherent, reusable platform.
• Design and build interchangeability between modeling paradigms: shared model inputs, coordinated results, and support for hybrid DES/ABM models.
• Advance 3D playback and in-run visualization of queues, throughput, wait times and resource use for complex facilities and operations.
• Define the interfaces between the simulation engine and Unity, including state streaming, simulation time and render time synchronization, and replay. Build prototypes and integration code, and review the team's engine and Unity work.

Digital Twin R&D

• Direct the R&D effort and author the technical roadmap for evolving our simulation platform into real-time digital twins fed by sensors, IoT devices and live operational data.
• Design the data integration, calibration and validation approach that keeps each twin's behavior accurate against the real world system it represents.
• Prototype and evaluate emerging capabilities, including AR/VR delivery of models and digital twins.
• Technical Leadership and Delivery
• Lead and mentor dedicated C# simulation engine and Unity developers, setting technical direction and priorities across a regular cadence of maintenance, feature and major releases.
• Set standards for model verification and validation, statistical output analysis (replications, convergence, sensitivity), version control and configuration management.
• Translate operational and analytical requirements from customers and our operations research team into maintainable, extensible software.

Customer Engagement and Growth

• Brief government stakeholders on architecture, digital twin roadmaps and model capabilities.
• Travel periodically to customer facilities to observe the operations being modeled.
• Shape new opportunities by leading solution demonstrations, technical approaches, white papers and proposals for digital twin and simulation work across DoD, DHS, the IC and civilian agencies.

• Bachelor's Degree in Engineering, Computer Science, Information Systems, or a related technical discipline.
• 7+ years of professional software development experience, including 5+ years designing or architecting simulation software (discrete event, agent based, or hybrid) at the engine or framework level, not only using simulation tools.
• Demonstrated digital twin experience: connecting a simulation or virtual model to real world data (sensors, IoT, telemetry, or streaming feeds) and using it to calibrate or validate model behavior.
• Strong C#/.NET proficiency: able to set architecture, review code, and build prototypes and integration code.
• Experience engaging directly with government customers and executive stakeholders.
• Excellent communication, presentation, and leadership skills.
• Ability to obtain and maintain a U.S. Government security clearance.

Preferred Qualifications

• Active Public Trust, Secret, or Top Secret security clearance.
• Working knowledge of Unity (or Unreal Engine), including how it consumes simulation state and its performance considerations.
• Experience with streaming and IoT data pipelines (e.g., Kafka, MQTT) and time-series data.
• AR/VR experience (e.g., Unity XR).
• R or Python for statistical analysis and model input/output processing.

Why Join The One 23 Group?

At O23G, you'll work alongside highly accomplished professionals supporting some of the nation's most important missions. You'll have the opportunity to lead cutting-edge engineering initiatives, collaborate directly with government customers, and help shape the future of Digital Engineering across the federal marketplace. If you're passionate about solving complex technical challenges, mentoring engineering teams, and delivering mission-focused solutions that make an impact, we'd love to hear from you.