Hire Top Freelance Systems Programming Developers

Olajide Olanrewaju

Freelance Systems Programming Developer5.0 (381 reviews)

I am a **Multi-talented** professional adept in **Full Stack Web Development**, **Web Security Research**, and **Robotics Engineering**. As a dedicated Web Security Researcher and ethical hacker, I uncover vulnerabilities and mitigate security risks, bridging the gap between development and cybersecurity. Additionally, as a Robotics Engineer, I design and build sophisticated robotic systems, applying my deep understanding of mechanics, electronics, and programming. Passionate about crafting clean, scalable code and innovative robotics solutions, I contribute to projects that prioritize both robust development, cybersecurity practices, and cutting-edge robotic technology.

Kirill Erokhin

I teach Operating Systems and functional programming fundamentals to CS students and guide fellow professionals through legacy codebase maintenance, practical software architecture, and new language/framework learning skills. For students, I offer two types of sessions - one is a lecture-style session where I can go over course notes/slides on a particular topics and offer additional explanations and examples to improve your understanding of the material. Another type is an assignment take-up session where I can go over a past assignment and guide you through steps to solving it. For working professionals, I offer the following options: * Focused problem-solving sessions - if you have a particular issue that you're stuck with in a project you're working on, I can pair with you over Zoom screen-sharing * Code review - if you cannot understand how to work with part of your codebase or if you'd like a second opinion on work that you've just completed, I can pair with you over Zoom and do a live code review and/or prepare ahead of time and go over my findings on a call * Long-term mentorship - if you would like to learn some more fundamental skills or pick up a framework/design pattern/best practices, I can develop a custom-tailored learning plan that fits your skill level and schedule and offer regular teaching sessions with optional take-home exercises A bit about me --- I am a tech founder and a senior polyglot/full-stack developer, with a passion for teaching and mentorship. In a bit of spare time from my work, I am looking to help fellow software developers get more comfortable with our craft and exercise my teaching skills while I'm at it. So far, I've done a wide range of work - web app front-end and back-end, data pipelines at scale, DevOps/infrastructure, mobile (quite a bit of iOS and previously some Android) and some security. I have a reasonable taste for UI design and user experience, despite that not being my primary specialization. The industries I've worked in so far were heavily concentrated around finance/banking/FinTech and GovTech, although I've also been a founding developer at a couple of B2C startups and learned a lot throughout that experience. My personal research interests include operating systems and programming language theory. As cliche as it sounds, I try to learn something new all the time and I consider this of vital importance to my professional skillset. I always prioritize systems understanding and learning how to learn over memorizing APIs - and it's a philosophy that I try to share with my students as well. Teamwork and constant exchange of expertise with my peers is a close second most important value to me. A software product can be almost meaningless without a team that welcomes learning from failures, encourages curiosity and fosters true human friendships, and empathy both towards each other and towards the customers of the software we create. New client intake process --- 1. Intro/triage call [free of charge] [15 min] - this is a Zoom video call where I try to understand your background, the problem you're looking to solve and whether I believe we'd be a good fit for a productive mentor/mentee relationship. 2. Supplemental terms acceptance - as an independent contractor and not an employee of Arc, I ask my clients to accept a few additional terms that make session time measurement, scheduling and work product acceptance more precise, and further clarify the extent of our mentorship relationship. 3. Creation of Freelance Job/Scheduled Session on Codementor - if you haven't done that yet, I will ask you to create and assign me a freelance job and/or a scheduled session with a precise description of the topics we would be covering. For certain sessions, preliminary preparation may be required - if that is the case, we would discuss the details and estimated time ahead of time and a Freelance Job would be required to cover the effort of the preparation. Availability --- Please take a look at my Codementor calendar to plan intro calls and sessions. Generally, I am available between 3:30pm and 8pm Eastern Time (New York/Toronto), Monday to Saturday, but I try to schedule all of my teaching engagements between 6pm and 8pm whenever possible. *IMPORTANT: Urgent sessions are unfortunately not available at this time.* I am currently working through Codementor as a mentor, and unable to work as an on-call freelance developer. Please also note that I cannot provide consultations over chat - in my experience, it's generally more time-consuming for everyone, and copy-pasting code over chat can get messy. For those reasons, I only work through Zoom video calls with screen sharing. If you have any questions about the process or would like to book a call, I am happy to chat on Codementor - I should be usually available Monday-Saturday, 1pm - 8pm Eastern Time, subject to my other engagements. While I try to respond as soon as I can, I may take up to one business day or longer depending on how busy my schedule might get.

Mayckon Giovani

I am a Principal Systems Engineer specializing in post-quantum cryptography, distributed systems, and security-critical infrastructure. My work focuses on designing and building high-performance systems where correctness, security, and resilience are non-negotiable — including blockchain protocols, IIoT platforms, cryptographic infrastructure, and globally distributed backend systems. I operate across the full systems stack, from protocol design and formal methods to low-level implementation in Rust and Go, as well as scalable backend architectures and DevSecOps environments. My primary focus is engineering infrastructure that remains secure and reliable in adversarial and post-quantum threat models. I actively contribute to open-source projects involving post-quantum cryptography, distributed infrastructure, and secure systems engineering. My interests include protocol correctness, formal verification, cryptographic protocol design, and building the next generation of quantum-resilient systems. I am particularly interested in collaborating on deep-tech, cryptography, distributed infrastructure, and security-critical systems where engineering rigor and architectural excellence are essential.

Mohammed Hassan

With over 15 years of experience across software engineering, architecture, and product leadership, I specialize in building high-performing engineering teams, architecting scalable systems, and driving strategic product delivery. As a Tech Lead and adjunct faculty member, I combine hands-on technical expertise with leadership, mentorship, and education to deliver enterprise-grade solutions while developing the next generation of engineers. Technology Stack: Mobile & Web: Flutter/Dart, React, Multi-tenant Architectures Cloud & Backend: AWS (AppSync, Amplify, Lambda), Firebase, GraphQL, REST APIs Languages: C/C++/C#, Dart, Java, Python, JavaScript/TypeScript Specialized: IoT, Embedded Systems, Edge AI, Information Security Architecture: Clean Architecture, Microservices, Event-Driven Systems Leadership & Roles: Tech Lead / Chapter Lead – Leading cross-functional teams of 8+ engineers Product & Engineering Manager – Driving product strategy and delivery Solutions Architect – Designing enterprise systems and multi-tenant platforms Educator & Mentor – Adjunct faculty + 300+ mentees on Codementor Key Expertise: Teaching computer science fundamentals and advanced topics Leading distributed engineering teams and establishing technical standards Architecting and delivering complex SaaS platforms Strategic product roadmapping and stakeholder management Building developer assessment frameworks and quality systems Mentoring engineers from junior to senior levels Educational Background: PhD Candidate, Computer Engineering (Edge AI Research) Master of Computer Engineering Master of Business Administration (MBA) Postgraduate Diploma, Software Development Skills (UNIX) Bachelor of Computer and Information Sciences Current Focus: Building scalable multi-tenant platforms, AI-driven development workflows, team capability development, and strategic consulting and education.

Ruslan Odintsov

I've been teaching programming since 2018 to people of different ages. I'm specialized mostly in teaching how to start programming from scratch: basics of programming languages + basics of computer science. But I always have in mind a long-term perspective for my students and try to develop useful skills just from the start of our work.

Erum Mehmood

Embark on a transformative coding journey with me, a visionary computer science expert and a passionate mentor, bringing over two decades of rich expertise in the dynamic realms of programming, data science, and software architecture. My technical skills span across a broad spectrum, including mastery in programming languages like Python, Java, C++, C, and Scala, along with a profound understanding of algorithms, data structures, and the complex art of software design. My research interests include big data analysis, semi-stream join algorithms, and real-time data warehousing. As a mentor, I've illuminated the path for students globally, from prestigious universities in the USA, Australia, Canada, and the UK, in a vast array of subjects from Big Data Analytics to Cyber Security, and advanced programming languages. Currently, I am a lecturer of Computer Science at a Higher Education Institute. My academic prowess is underscored by a **PhD** in Computer Science, with my doctoral thesis titled: "Integrated Real-Time Distributed Stream-Disk Processing Architecture for Unstructured Big Data". Join me on codementor, where together, we'll navigate the intricacies of technology, unleashing the potential to innovate, solve real-world problems, and excel in your programming career.

Paul Stewart

PAUL STEWART ============ Portland, OR +1 (617) 697-4119 | paul@arckinteractive.com | LinkedIn Available Upon Request SUMMARY ------- Technology leader with 20+ years of experience spanning enterprise IT infrastructure, secure cloud architecture, software development, and regulatory compliance. Cyber AB Registered Practitioner (RP) and Director of Cybersecurity Compliance with hands-on expertise in Microsoft 365 GCC High, Azure, identity governance, endpoint lifecycle management, and secure enclave design. Proven ability to lead cross-functional engineering teams, modernize infrastructure, deliver SaaS platforms, and translate complex compliance requirements (CMMC, NIST SP 800-171, HIPAA, SOC 2, FISMA) into operationally sustainable technical solutions. Equally comfortable operating at the executive strategy level and in hands-on technical implementation. CORE COMPETENCIES ----------------- • IT Infrastructure & Operations Leadership • Microsoft 365 E5 Administration & Licensing Governance • Azure & Hybrid Cloud Architecture • Identity & Access Management (Entra ID / Azure AD / MFA / Conditional Access) • Intune Endpoint Lifecycle Management & Patch Governance • Secure Enclave & Network Segmentation Design • Cybersecurity & Regulatory Compliance (CMMC L2, NIST 800-171, HIPAA, SOC 2, FISMA) • Full-Stack SaaS Architecture & Systems Integration • DevOps & Infrastructure as Code (CI/CD, Docker, Cloud Automation) • Risk, Issue & Change Management • Executive Advisory & Stakeholder Communication • Agile & Hybrid Delivery (Scrum, Kanban, PMI) PROFESSIONAL EXPERIENCE ----------------------- ### FNI, INC. **Director of Cybersecurity Compliance | Cyber AB Registered Practitioner** Nov 2025 – Present | Tigard, OR Lead CMMC Level 2 implementation and secure infrastructure operations within Microsoft GCC High environments, integrating identity, endpoint, logging, and compliance governance into scalable enterprise architectures. • Own operational security posture of Microsoft 365 GCC High enclave including Entra ID, Conditional Access, Intune compliance baselines, Defender, and Sentinel logging configurations. • Lead identity-first Zero Trust architecture, enforcing MFA, device compliance gating, privileged role governance, and separation of duties controls. • Oversee endpoint lifecycle management, patch governance, secure configuration standards, and application control policies. • Define and optimize CUI system boundaries, network segmentation, VLAN isolation, and air-gapped containment strategies for legacy systems. • Author and maintain SSPs, POA&Ms, and objective-level evidence (320 assessment objectives) aligned to NIST SP 800-171 and CMMC Level 2. • Coordinate cross-functional engineering and MSSP teams to meet aggressive remediation and certification timelines. • Serve as executive advisor on regulatory interpretation, risk posture, and secure infrastructure strategy. ### ARCK INTERACTIVE, INC. **Founder & CTO** September 2010 – Present Founded and scaled a full-stack digital product and infrastructure consultancy serving healthcare, nonprofit, education, and enterprise SaaS clients. Directed the full lifecycle of infrastructure modernization and secure platform development initiatives. • Designed and implemented Microsoft 365, Azure, and AWS cloud environments supporting distributed teams and regulated workloads. • Led migrations from on-premises infrastructure to hybrid and cloud-first architectures. • Managed identity governance, endpoint security, licensing strategy, and operational security baselines across client environments. • Oversaw DevOps automation pipelines (CI/CD, containerization, Infrastructure as Code) to support secure, repeatable deployments. • Established governance frameworks, risk registers, and communication plans ensuring consistent delivery across multimillion-dollar programs. • Delivered 100+ SaaS and digital transformation projects on time and within budget, including system integrations for The World Bank, University of Alaska, and John Wiley & Sons. • Ensured compliance with SOC 2, HIPAA, ADA, FERPA, and related regulatory standards through structured audit documentation and QA controls. ### CHENEGA CORPORATION (U.S. Department of Transportation) **Senior Full-Stack Developer / Federal Solutions Architect** August 2005 – August 2010 Led design and delivery of secure federal systems operating under FISMA and NIST 800-53 controls. • Architected and delivered national-scale compliance platforms (SAMO, RISC) within high-assurance federal environments. • Developed project charters, scope definitions, and detailed work breakdown structures for multi-team development efforts. • Managed risk assessments, mitigation strategies, and audit readiness in coordination with federal oversight bodies. • Introduced early CI/CD automation and governance dashboards to improve delivery efficiency and compliance visibility. • Transitioned teams from waterfall to Agile methodologies while preserving federal reporting requirements. ### TUFTS MEDICAL CENTER (Perot Systems) **Web Developer / Application Analyst** March 2002 – August 2005 • Designed and implemented a HIPAA-compliant .NET-based CMS supporting 85+ hospital departments with role-based access control (RBAC). • Integrated Lawson ERP and EHR systems to eliminate manual reconciliation and improve data integrity. • Directed stakeholder workshops, requirements analysis, and QA testing aligned with healthcare compliance standards. ### TUFTS MEDICAL CENTER (Lifespan Inc.) **Project Lead / Applications Analyst** January 1999 – March 2002 • Standardized enterprise workstation builds and Active Directory provisioning across 1,000+ endpoints. • Led rollout of remote access and network security policies. • Partnered with clinical leadership to improve SLA performance and implement structured change management. TECHNICAL TOOLKIT ----------------- **Cloud & Infrastructure:** Microsoft 365 GCC High, Azure Government, Azure AD / Entra ID, AWS, GCP, Docker, CI/CD Pipelines, Infrastructure as Code **Endpoint & Security:** Microsoft Intune, Microsoft Defender, Microsoft Sentinel, Conditional Access, MFA, RBAC, Secure Baselines **Development:** .NET, Node.js, Python, PHP, Laravel, JavaScript, TypeScript, React, Vue.js **Data & Integration:** REST APIs, GraphQL, HL7, FHIR, OAuth2, SSO, MySQL, PostgreSQL, MongoDB, Elasticsearch **Governance & Compliance:** CMMC Level 2, NIST SP 800-171, NIST 800-53, FISMA, HIPAA, SOC 2, FERPA, ADA **Tooling:** Jira, Confluence, GitHub, Jenkins, Postman, Slack EDUCATION --------- Bachelor of Science – Multimedia Studies & Computer Engineering Northeastern University Master’s Coursework – Communication Protocols & Internet Architectures Harvard Extension School CERTIFICATIONS -------------- Cyber AB Registered Practitioner (RP) PMP – Project Management Professional (PMI) Agile / Scrum / Kanban Methodologies REFERENCES HENRY DITTMER ([henry@sensible-leadership.com](mailto:henry@sensible-leadership.com)) To whom it may concern, It’s a pleasure to recommend Paul Stewart for any senior leadership role. I’ve collaborated with Paul during a crucial phase of a client’s transformation initiative. I brought him into the project based on a trusted recommendation, and it turned out to be one of the most strategic decisions we made. With decades of experience in technology and business, I was struck by Paul’s blend of technical expertise and strategic foresight. He has a rare ability to convert vision into execution, modernizing how teams operate while ensuring long-term sustainability. Paul introduced agile methodologies that allowed us to shift from rigid development cycles to rapid, iterative delivery. This significantly accelerated our ability to deliver value. Paul’s strength lies in balancing big-picture thinking with detailed execution. He’s analytical, intuitive, and responsive to shifting priorities. He streamlined processes, introduced scalable architecture, and guided the team through continuous improvements—all with unwavering integrity and transparency. As a leader and consultant, Paul communicates clearly, mitigates risks early, and inspires high performance. He led a diverse, distributed team with empathy and precision, aligning technical contributors and stakeholders alike. Every milestone was delivered reliably, and the results surpassed expectations in terms of usability, durability, and strategic value. Paul leads with a strong sense of purpose. He brings intellectual clarity and emotional intelligence to every engagement. Any organization would benefit immensely from his leadership, systems thinking, and commitment to meaningful outcomes. Please feel free to contact me directly for more insight. Sincerely, Henry C. Dittmer Sensible Leadership Coaching, LLC [henry@sensible-leadership.com](mailto:henry@sensible-leadership.com) +1 (303) 810-4905 BEN TOMLIN ([btomlin@uw.edu](mailto:btomlin@uw.edu)) I’m pleased to share my wholehearted recommendation of Paul Stewart. I originally worked with Paul at the intersection of technology and learning innovation. At a time when digital collaboration was just beginning to take shape, Paul helped us envision and execute an ambitious solution that merged content, community, and utility in a single, intuitive system. What impressed me most was Paul’s ability to deeply understand the people at the center of the work. He actively engaged all stakeholders—whether strategic leaders or frontline users—to co-design meaningful outcomes. He guided us through choices with clarity, balancing bold innovation with practical delivery. The result was something visionary, built well before many of today’s mainstream tools emerged. And yet Paul’s strength wasn’t just technical—it was his commitment to solving real- world problems and advancing the mission through design and engineering. Even as our careers progressed, I’ve remained inspired by Paul’s foundational approach: engage thoughtfully, build iteratively, and measure success by impact. The principles I observed in those early years have clearly endured in the way he continues to lead teams and deliver change across sectors. I hold Paul in the highest regard as an innovator, mentor, and leader. Any forward-thinking organization would benefit greatly from his presence. Warmly, Ben Tomlin Senior Director, Communications [btomlin@uw.edu](mailto:btomlin@uw.edu) To whom it may concern, It’s my pleasure to offer this recommendation for Paul Stewart, whom I’ve had the opportunity to work with closely over the past several years on the development and continuous evolution of a specialized digital platform. From the beginning, Paul brought more than just technical expertise—he approached the work as a strategic partner. He took time to understand the needs and dynamics of our clients and end users, and he translated that understanding into a platform that was not only robust and secure, but remarkably intuitive. Paul was instrumental in shaping a product that handles complex workflows and permissions without ever losing sight of user experience. One of the things I appreciate most about Paul is his ability to manage complexity with calm clarity. He leads with thoughtfulness, listens intently, and never loses sight of what success looks like for the people on the other side of the screen. Under his leadership, projects were delivered on time and under budget, and always with scalability and adaptability in mind. Beyond the technical scope, Paul has been a valued thought partner as our work has grown. Whether navigating tight timelines or evaluating new opportunities, I’ve consistently relied on his clear thinking, grounded perspective, and collaborative spirit. His contributions have made our work stronger and more resilient. Any team would benefit from Paul’s ability to turn ambiguity into action and vision into results. I recommend him enthusiastically. Warm regards, Shannon Berg Founder & CEO [shannon@bergassociatesnw.com](mailto:shannon@bergassociatesnw.com) 503.347.8822 TYSON BROWN ([brown.tyson@gmail.com](mailto:brown.tyson@gmail.com)) It is my pleasure to recommend Paul Stewart for senior leadership and strategic delivery roles. I worked closely with Paul in my capacity as a Product Manager, where he served as a consulting partner and development lead to help us drive and deliver compelling capabilities to our customer base. When we faced the challenge of building a new system under a short timeline and with high technical expectations, Paul’s team stepped in and delivered beyond expectations. He quickly absorbed the complexity of our business problem and translated it into a thoughtful, strategic technical solution. He worked with us from discovery through deployment, balancing technical feasibility with user-centric design and organizational priorities. Paul’s leadership was crucial to the success of this initiative. He assembled and guided a hybrid team of frontend, backend, and QA engineers who worked in close collaboration with our in- house teams. His calm and focused presence helped maintain momentum through tight deadlines, shifting requirements, and technical unknowns. The product we launched achieved exceptional adoption rates and remains a critical, high-use capability today. As a development manager, Paul consistently solved difficult problems with elegance and empathy. He is fluent in both the language of business and technology, serving as a vital bridge between strategic goals and technical execution. His standards for quality and innovation were evident in every deliverable. Equally important, Paul led with integrity and transparency. He built trust quickly with our teams and fostered a culture of accountability within the distributed team he managed. His hybrid-first team structure and leadership approach predated current remote trends by over a decade, serving as a model for high-performing global teams. Paul brings strategic thinking, operational discipline, and a collaborative spirit to every engagement, making him a valuable asset to any organization. Please feel free to contact me directly should you wish to discuss his candidacy further. All the best, Tyson Brown LinkedIn 480-399-9899 [brown.tyson@gmail.com](mailto:brown.tyson@gmail.com)

Chris

Senior Software Engineer with 8+ years of experience in developing, maintaining and performing optimization techniques for all sorts of amazing projects using controllers like Arduino, ESP32, Nvidia Jetson, Ti Hercules and many more. I work full-time as an Engineer in the Automotive sector using languages such as C, C++, Python and C#. Next to these I bring a broad skillset in frameworks such as Nvidia Cuda, ROS and FreeRTOS. I love to share my knowledge with other developers so that they can grow and accomplish their goals.

Vivek Kumar Verma

LinkedIn : https://www.linkedin.com/in/vivek-kumar-verma-29410460/ I am a Software Development Engineer with around 5+ years of experience that loves developing solutions to improve processes of everyday activities. I am working as Software Development Engineer at Expedia and I am also the part of the hiring team. I regularly take interviews for Coding and Design rounds. I can help you out. Please message me in private chat to discuss further. I am having an avid interest in Algorithms and Data Structures. I am strong engineering professional with a Bachelor of Technology (B.Tech.) focused in Computer Science and Engineering from Motilal Nehru National Institute of Technology (NIT), Allahabad - India. I have great experience developing applications in Java with Spring Boot. My Technical Skills are as follows : • Proficient in Data Structures and Algorithms • Object Oriented Programming • Programming Languages: C, C++, Java. • Scripting Languages: Python (Intermediate), Linux Shell Scripting • Web Technologies: HTML, CSS, Angular 4 • Frameworks: Spring Boot, Amazon AWS, REST/SOAP • Databases: MySQL • Web/Application Servers: Apache Tomcat • Operating Systems: Windows, Linux, Android, Juniper Junos • Tools: Postman, IntelliJ, Eclipse, Maven, Eclipse, Wireshark, GDB. • Testing: JUnit, JMeter, Mockito, Unit Testing. I have : • Designed and coded application components using Agile and scrum methodologies while applying them in practice. • Entrusted to take up complex task/problems to come up with solutions and delivering it on-time. Please connect with me on LinkedIn. Thanks!

Raj Kumar

I’m a software engineer at Google, where I work on systems that handle terabytes of data at scale. My core interests lie in data structures & algorithms ,distributed systems, and system design. I enjoy solving large-scale engineering challenges, designing resilient architectures, and optimizing performance for high-throughput systems. Beyond my current role, I’m deeply passionate about building scalable backend infrastructures, exploring concurrency, and continuously improving my expertise in advanced system design.