On-site - Senior Full-Stack Software Engineer

Senior Full-Stack Software Engineer

Telecom Platforms | Node.js, React, APIs & Legacy Modernization

Company: QuestBlue
Location: Morrisville, North Carolina (Research Triangle Park)
Employment Type: Full-Time
Work Schedule: Monday–Thursday On-Site | Friday Remote
Salary: $110,000 to $120,000 annually, based on experience

About QuestBlue

QuestBlue is an established telecommunications provider with almost two decades of experience delivering VoIP, SMS, fax, and communications solutions.

We develop and operate proprietary software platforms supporting our customers, telecommunications services, billing operations, provisioning, and internal business processes.

We are seeking an experienced, hands-on Senior Full-Stack Software Engineer to take primary ownership of the ongoing development, maintenance, and modernization of our applications.

This is a senior individual-contributor position for someone who enjoys writing code, solving complex problems, and independently delivering reliable software.

You will work directly with company leadership and collaborate with our dedicated infrastructure and database professionals.

Our infrastructure, database administration, networking, security, backups, and telecommunications switching environments are managed by a separate team of experienced professionals. Your focus will be software engineering.

What You'll Work On

Your primary focus will be our modern customer portal and API platform, which includes:

• Node.js 22, Express, and Sequelize
• React 19, Vite, and Tailwind CSS
• TanStack Query and TanStack Table
• Socket.io
• MySQL / MariaDB
• RabbitMQ and Redis
• JWT, TOTP, and API validation
• Docker and Git-based development workflows

Our broader software environment also includes:

• Python / Django: Applications and services supporting our fax platforms
• .NET: Services responsible for Call Detail Record (CDR) billing and processing
• PHP: Production applications supporting PBX services, administrative operations, and internal platforms
• Kotlin Multiplatform: Applications supporting our next-generation softphone

You are not expected to be an expert in every technology listed. We value strong engineering fundamentals, the ability to understand unfamiliar applications, and the willingness to work across different codebases.

What You'll Do

• Design, develop, maintain, and improve customer-facing and internal applications.
• Build and maintain backend APIs using Node.js and related technologies.
• Develop modern React interfaces integrated with production APIs and real-time services.
• Maintain and enhance existing PHP and Python applications.
• Develop integrations with telecommunications carriers, billing systems, provisioning services, and third-party APIs.
• Work with RabbitMQ, Redis, and asynchronous application workflows.
• Write efficient SQL queries and develop database-driven application functionality.
• Collaborate with our database administration team on schema changes, query optimization, and application data requirements.
• Investigate and resolve application bugs, performance issues, and production errors.
• Maintain and modernize legacy applications without disrupting existing functionality.
• Develop automated tests and validate changes before production release.
• Review existing code and recommend improvements to security, performance, reliability, and maintainability.
• Work with GitHub repositories, pull requests, and established development workflows.
• Coordinate with our infrastructure team when software changes require deployment or environment support.
• Independently manage development tasks from requirements through implementation, testing, and completion.
• Help establish and maintain clear technical documentation for our applications and integrations.

This position involves both new development and the ongoing maintenance of existing production software.

Required Qualifications

We are looking for a senior engineer with strong full-stack development experience, particularly in modern JavaScript technologies and backend application development.

Required technical experience:

• Strong proficiency in Node.js and modern JavaScript/TypeScript.
• Strong experience developing applications using React.
• Experience designing and maintaining REST APIs.
• Solid experience with MySQL/MariaDB and SQL-based application development.
• Understanding of relational database transactions, indexing, and data integrity.
• Experience with RabbitMQ or comparable message-queue technologies.
• Experience with Redis or comparable caching and data-store technologies.
• Familiarity with Docker and Docker Compose development environments.
• Experience with Git, GitHub, and modern software development workflows.
• Understanding of application authentication, authorization, and security practices.
• Experience troubleshooting production applications and resolving complex software issues.
• Ability to understand, maintain, and improve existing applications with limited documentation.

Equally important:

• Ability to work independently with minimal supervision.
• Strong problem-solving and debugging skills.
• Sound judgment when modifying business-critical production applications.
• Ability to balance maintenance, troubleshooting, and new development.
• Clear communication and effective collaboration with other technical professionals.
• A practical approach to software engineering that prioritizes reliability and maintainability.

We value demonstrated engineering ability and real-world production experience over certifications or familiarity with every framework.

Preferred Qualifications

Experience with any of the following would be beneficial:

• Python and Django
• PHP and legacy PHP frameworks
• .NET and C#
• PostgreSQL
• WebSockets and real-time applications
• Distributed applications and asynchronous processing
• Automated testing and application performance optimization
• Telecommunications carrier API integrations
• Billing, provisioning, or customer management systems
• Kotlin Multiplatform or mobile application development

Telecommunications experience is a significant advantage, particularly familiarity with:

• SIP and RTP
• Asterisk and FreeSWITCH
• Call Detail Records (CDRs)
• Telecom billing and rating
• SMS carrier integrations and webhooks
• Fax platforms and T.38
• E911 services
• Telephone number provisioning

Telecommunications experience is preferred but not required. Strong software engineering fundamentals and the ability to learn established applications are more important.

Dedicated Infrastructure & Database Support

QuestBlue maintains a separate professional infrastructure team responsible for:

• Server administration and Proxmox virtualization
• Networking, switching, firewalls, and data center operations
• High availability, replication, monitoring, and backups
• MariaDB/MySQL database administration, tuning, and protection
• Database infrastructure, replication, and recovery
• CI/CD runners and deployment infrastructure
• Infrastructure security and system maintenance
• Asterisk, FreeSWITCH, Sipwise, and Kamailio infrastructure administration

This is a software engineering position, not a DevOps, systems administration, or database administration role.

You will develop database-driven applications and work with SQL, but our experienced database professionals handle the underlying database infrastructure, administration, replication, backups, and production optimization.

You will also have access to experienced technical resources for architectural guidance, specialized assistance, and complex troubleshooting when needed.

This structure allows our in-house software engineer to concentrate on building, maintaining, and improving our applications.

Legacy Modernization

QuestBlue operates mature telecommunications applications alongside newer platforms.

Some systems use older PHP/Kohana applications, legacy Django services, or other technologies that are progressively being modernized.

We believe successful modernization requires understanding existing business logic, preserving production stability, reducing technical debt, and making thoughtful improvements.

We are not looking for someone who immediately wants to rewrite every legacy application.

We want an engineer who can understand why an application works the way it does, identify opportunities for improvement, and safely evolve the platform.

AI-Assisted Software Development

QuestBlue embraces modern development tools and practices that improve engineering productivity.

Experience with AI-assisted development tools such as GitHub Copilot, ChatGPT, Claude Code, or similar technologies is strongly preferred.

We encourage responsible use of these technologies to accelerate:

• Code analysis and troubleshooting
• Software development and refactoring
• Automated testing
• Technical documentation
• Understanding unfamiliar codebases
• Identifying opportunities for application improvements

Our engineers remain responsible for validating generated code, maintaining application security, and ensuring production reliability.

The Engineer Who Will Succeed at QuestBlue

The ideal candidate is someone who enjoys being a hands-on software engineer.

You are comfortable moving between React, Node.js, SQL, backend services, and existing applications.

You don't need a large development team to accomplish meaningful work.

You take ownership of problems, investigate them thoroughly, and follow them through to resolution.

You understand that software supporting telecommunications, billing, and customer operations must be reliable and accurate.

You are comfortable maintaining established systems while developing new features and improving existing functionality.

You know when to introduce new technology and when the better engineering decision is to improve what already works.

You communicate clearly, make practical technical decisions, and take pride in delivering software that works.

We are not looking for someone whose primary interest is managing developers or overseeing projects from a distance. We are looking for a capable, hands-on engineer who enjoys writing code and taking ownership of applications.

Why Join QuestBlue?

• Take meaningful ownership of established, production telecommunications software.
• Work directly with company leadership and have a visible impact on the business.
• Develop new applications and improve existing platforms.
• Work across modern technologies and established production systems.
• Focus on software engineering without being responsible for server, network, or database administration.
• Collaborate with experienced infrastructure and database professionals.
• Work in an environment that values practical solutions, independence, and technical competence.
• Utilize modern development tools, including AI-assisted programming.
• Enjoy a consistent Monday–Thursday office schedule with remote Fridays.

Work Environment:

Schedule:

• Monday through Thursday: On-site
• Friday: Remote
• Dental, Vision, Health Insurance, Paid holidays, Paid Time Off, Retirement (401k), Bonus.

Location: On-Site at our Morrisville, NC (off Hwy 40 near RDU Airport).

Employment: Full-Time

Base Salary: $110,000 to $120,000 annually, commensurate with experience and demonstrated technical ability.

Apply

If you are an experienced full-stack engineer who enjoys solving real-world problems, working independently, and taking ownership of business-critical applications, we would like to hear from you.

Join QuestBlue and help shape the next generation of our telecommunications software platforms.

QuestBlue Systems, Inc is a fast-paced ITSP (Internet Telephone Service Provider) that is aggressively working towards becoming a Fast 500 company. QuestBlue Systems offers wholesale VoIP as a SIP Trunk Provider. With a fully functioning end user portal, users can provision their telecommunications in real time such as, SIP Trunks, DIDs, e911 and many other important SIP / VoIP needs.