Senior UI/UX & API Developer

Designer Jobs; Belleville (IL); Hybrid; USD 120,000 - 160,000; Full time

Benefits offered by this job

Competitive salary

Comprehensive benefits

401(k)

Bonus and profit sharing

Flexible hours

Education reimbursement

Generous paid time off

Job summary

D&G Support Services, LLC is seeking a Senior UI/UX & API Developer to modernize applications, delivering secure, responsive web experiences and RESTful APIs in a hybrid Agile DevSecOps environment. Based in Belleville, IL, this role requires active Secret clearance and U.S. person eligibility.

The position covers front-end and back-end development, testing, and sustainment across systems while aligning to 508 accessibility standards and security best practices.

Qualifications

• Eight (8) or more years of professional software-development experience, including complex enterprise web applications and system integrations.
• Hands-on experience with JavaScript/TypeScript, HTML, CSS, and modern front-end frameworks such as React, Angular, or comparable technologies.
• Experience translating functional requirements and user workflows into production-ready interfaces, reusable components, and practical UX designs.
• Experience developing RESTful APIs, web services, microservices, and enterprise integrations using Java, C#, Python, or comparable technologies, including API contracts and documentation using OpenAPI/Swagger.
• Working knowledge of relational databases, SQL, data-access patterns, and application-to-database integration.
• Experience with Git, CI/CD, automated testing, secure coding, authentication/authorization, input validation, and application-security practices.
• Experience developing accessible enterprise or federal web applications, including applicable Section 508 requirements.
• Bachelor’s or Master’s degree in Computer Science, Cybersecurity, Data Science, Software Engineering, Information Technology, Information Systems, or related software-engineering discipline; or certifications: FITSP-D, GCSA, GISF, SSCP.

Responsibilities

• Design, develop, test, and sustain secure, responsive, accessible web applications and reusable front-end components using JavaScript/TypeScript, HTML, CSS, and frameworks such as React or Angular.
• Convert mission workflows and user requirements into intuitive interfaces, user flows, wireframes, prototypes, reusable components, and accessible experiences that support Section 508 requirements.
• Build and maintain RESTful APIs, web services, microservices, and integration components using Java, C#, Python, or comparable technologies, including API contracts, data models, validation rules, error handling, versioning, and interface documentation.
• Integrate applications and APIs with relational databases, data services, analytics platforms, and existing enterprise interfaces while maintaining business rules and data integrity.
• Implement secure authentication, authorization, role-based access, input validation, logging, auditing, and other application-security controls; troubleshoot API, integration, performance, data-mapping, and connectivity issues.
• Create unit, API, integration, accessibility, and automated regression tests, and support build, testing, security validation, and deployment activities through GitLab CI/CD processes.
• Participate in Agile delivery activities, including requirements refinement, sprint planning, demonstrations, GVT/GAT, release readiness, production support, and defect resolution.
• Provide technical leadership through design and code reviews, mentoring, documentation, technical-debt identification, and collaboration with developers, architects, data engineers, DevSecOps, cybersecurity personnel, testers, Product Owners, and Government stakeholders.

Skills

JavaScript/TypeScript

HTML

CSS

React

Angular

RESTful APIs

Java

C#

Python

GitLab CI/CD

Agile

Section 508

Education

Bachelor’s or Master’s degree in Computer Science, Cybersecurity, Data Science, Software Engineering, IT, IS, or related

FITSP-D

GCSA

GISF

SSCP

Tools

OpenAPI/Swagger

Figma

Adobe XD

Job description

D&G Support Services, LLC is hiring a Senior UI/UX & API Developer to support application modernization tied to the IGC Contract. This role helps deliver secure, responsive, and accessible web experiences along with RESTful APIs in a hybrid Agile DevSecOps environment, with work designed to align to Section 508 requirements.

The position is based in Belleville, IL (hybrid) and supports development, testing, and sustainment across front-end and back-end capabilities. Active Secret clearance and U.S. person eligibility are required.

Responsibilities

• Design, develop, test, and sustain secure, responsive, accessible web applications and reusable front-end components using JavaScript/TypeScript, HTML, CSS, and frameworks such as React, Angular, or comparable technologies.
• Convert mission workflows and user requirements into intuitive interfaces, user flows, wireframes, prototypes, reusable components, and accessible experiences that support applicable Section 508 requirements.
• Build and maintain RESTful APIs, web services, microservices, and integration components using Java, C#, Python, or comparable technologies, including API contracts, data models, validation rules, error handling, versioning, and interface documentation.
• Integrate applications and APIs with relational databases, data services, analytics platforms, and existing enterprise interfaces while maintaining business rules and data integrity.
• Implement secure authentication, authorization, role-based access, input validation, logging, auditing, and other application-security controls; troubleshoot API, integration, performance, data-mapping, and connectivity issues.
• Create unit, API, integration, accessibility, and automated regression tests, and support build, testing, security validation, and deployment activities through GitLab CI/CD processes.
• Participate in Agile delivery activities, including requirements refinement, sprint planning, demonstrations, GVT/GAT, release readiness, production support, and defect resolution.
• Provide technical leadership through design and code reviews, mentoring, documentation, technical-debt identification, and collaboration with developers, architects, data engineers, DevSecOps, cybersecurity personnel, testers, Product Owners, functional analysts, and Government stakeholders.

Requirements

• Eight (8) or more years of professional software-development experience, including complex enterprise web applications and system integrations.
• Hands-on experience with JavaScript/TypeScript, HTML, CSS, and modern front-end frameworks such as React, Angular, or comparable technologies.
• Experience translating functional requirements and user workflows into production-ready interfaces, reusable components, and practical UX designs.
• Experience developing RESTful APIs, web services, microservices, and enterprise integrations using Java, C#, Python, or comparable technologies, including API contracts and documentation using OpenAPI/Swagger or similar approaches.
• Working knowledge of relational databases, SQL, data-access patterns, and application-to-database integration.
• Experience with Git, CI/CD, automated testing, secure coding, authentication/authorization, input validation, and application-security practices.
• Experience developing accessible enterprise or federal web applications, including applicable Section 508 requirements.
• Bachelor’s or Master’s degree in Computer Science, Cybersecurity, Data Science, Software Engineering, Information Technology, Information Systems, or a related software-engineering discipline; or one of the following certifications: FITSP-D, GCSA, GISF, or SSCP.
• Strong technical leadership, troubleshooting, design-review, mentoring, documentation, and stakeholder-communication skills.

Technologies

• JavaScript, TypeScript, HTML, CSS, React, Angular
• Java, C#, Python
• RESTful APIs, microservices, OpenAPI/Swagger
• SQL, Git, GitLab CI/CD
• Section 508

Benefits

• Competitive salary
• Comprehensive benefits
• 401(k)
• Bonus and profit sharing
• Flexible hours
• Education reimbursement
• Generous paid time off

Preferred

• Experience supporting U.S. Transportation Command, Department of Defense logistics, or another mission-critical federal system.
• Experience modernizing legacy enterprise user interfaces and web services while maintaining operational continuity.
• Experience with UX design and prototyping tools such as Figma, Adobe XD, Sketch, or comparable products.
• Experience with enterprise identity and access management, single sign-on, and role-based access-control patterns.
• Experience integrating applications with business-intelligence or analytics platforms such as Apache Superset.
• Familiarity with Oracle, PostgreSQL, Amazon Aurora, Amazon RDS, or comparable relational databases.
• Familiarity with containerized and AWS-hosted environments, DevSecOps practices, DoD Risk Management Framework, and STIG/SRG requirements.

Clearance and Eligibility

• Active Secret security clearance or the ability to obtain and maintain one, as required by assigned duties and contract requirements.
• Restricted to U.S. person(s) (U.S. citizens, permanent residents, and other protected individuals under 8 U.S.C. 1324b(a)(3)).

Location

• Hybrid
• Remote work may be authorized consistent with program requirements.
• Personnel must be available for required on-site meetings, user-engagement activities, testing, demonstrations, release activities, classified-system access, or other assigned mission needs at Scott Air Force Base, Illinois.