[Remote] Senior Software Developer, Full Stack

Note: The job is a remote job and is open to candidates in USA. RS21 is seeking a Senior Software Developer, Full Stack to lead hands-on engineering, software architecture, client-facing solutioning, and cross-functional technical delivery. The role owns complex application systems and platform services, leads AI-powered development and technical execution, mentors developers, and contributes to client engagements and business development.

Responsibilities

• Author scalable, maintainable application code across the full stack; set architecture patterns for active projects, establish coding conventions, and ensure that architectural decisions are documented with rationale and trade-offs
• Design and deliver production-grade application systems, APIs, and services on AWS; govern engineering standards across active projects and ensure junior engineers understand and operate to those standards
• Architect application security, including IAM design, secrets management, secure service-to-service communication, and defense-in-depth practices appropriate to the client's environment
• Architect robust CI/CD systems for assigned projects; mentor team on testing strategy, pipeline governance, release practices, and how to design deployments that fail safely
• Architect scalable container platforms using Docker and Kubernetes; mentor team on Helm, cluster governance, resource management, and workload optimization for production environments
• Lead LLM application development across complex client use cases with deep expertise in prompt engineering, chain design, tool use, and responsible deployment; mentor team on advanced prompting, evaluation, and governance
• Architect complex multi-agent systems using LangGraph, AutoGen, CrewAI, or equivalent; mentor team on reliability, observability, agent state management, and safety patterns for production deployment
• Integrate AI coding tools into team engineering workflows; coach developers on responsible use, set standards for AI-assisted code review, and shape a code quality culture that benefits from AI acceleration without depending on it
• Design and optimize application architecture for LLM-backed features; make and document decisions about latency, cost, context window management, and fallback behavior
• Lead client software discovery and requirements-gathering sessions; translate ambiguous business and operational needs into concrete, documented technical architectures with clear assumptions, trade-offs, and open questions
• Produce reference architectures, solution design documents, and technical roadmaps that guide both client delivery and internal product development; write for audiences ranging from engineering teams to executive stakeholders
• Assess and document client technical readiness for modernization, AI adoption, and platform integration; identify gaps and prescribe actionable remediation paths in terms of business impact
• Serve as a technical coordination point between client stakeholders, data engineering, data science, platform engineers, and DevOps; translate across disciplines so every team has the context they need
• Contribute to RS21 business development and proposal efforts; produce technical approach sections, architecture diagrams, and scope estimates that reflect genuine senior-level expertise
• Own end-to-end technical execution planning for software development workstreams; define the sequence of work, identify dependencies, and ensure delivery milestones map to both technical and business outcomes
• Decompose complex client initiatives into structured Jira epics, stories, and tasks with clear acceptance criteria; help junior developers understand how their individual tasks connect to the larger delivery arc
• Partner with project managers and product owners to ensure the technical execution plan stays aligned with contractual, operational, and business constraints; surface risks early with enough context for leadership to act
• Lead planning, estimation, and architecture review ceremonies with the technical authority to drive hard decisions to resolution; help teams make good choices under ambiguity
• Mentor and grow junior and mid-level developers in technical depth, architectural thinking, and engineering craft; invest in their development with the specificity and consistency that actually produces growth
• Conduct code reviews, architecture reviews, and design critiques that elevate team output quality; give feedback that is specific, actionable, and calibrated to help the recipient improve
• Build and maintain engineering standards, internal playbooks, and onboarding materials for the software engineering practice; make RS21's engineering capability portable, consistent, and independent of any single person
• Help the team understand not just what to build, but why it matters and how engineering decisions connect to client outcomes and RS21's broader technical strategy
• Collaborate with data engineers and data scientists building AI and analytics features to ensure application architecture meets data pipeline and model requirements; understand the full technical stack well enough to design for it
• Influence clients and internal stakeholders through evidence-based, technically grounded narratives; make complex architectural decisions understandable to non-technical audiences without oversimplifying
• Document software architectures, API designs, and engineering best practices to support transparency, reuse, and knowledge transfer across RS21's software engineering practice
• Contribute to RS21 business development and proposal efforts as a credible senior engineering voice; review proposal sections, contribute technical content, and help ensure RS21 wins software work worth doing

Skills

• Bachelor's degree in Computer Science, Software Engineering, or a related field
• 7+ years of hands-on software development experience, including at least 3 years in a lead or senior engineering role with ownership of complex application delivery
• Deep expertise with modern application architectures including microservices, event-driven systems, API design, and security-by-design principles
• Demonstrated proficiency in one or more backend languages and modern front-end frameworks; able to produce and govern production-grade code across the stack
• Proven ability to deliver production-grade applications on AWS using ECS/EKS, Lambda, API Gateway, DynamoDB, RDS, and S3 at client-facing scale
• Demonstrated experience integrating LLM or AI capabilities into production applications with appropriate reliability, governance, and performance standards
• Proven ability to mentor junior developers and lead technical delivery across cross-functional teams in client-facing environments
• Strong written and verbal communication skills; experienced translating architectural decisions for stakeholder audiences at multiple levels
• Advanced degree a plus
• AWS Solutions Architect Professional or Developer Associate certification
• Experience with infrastructure-as-code tools such as Terraform or CDK and DevOps/CI-CD practices at production scale
• Experience with multi-agent orchestration frameworks and advanced prompt engineering in production deployments
• Background in consulting, professional services, or multi-client delivery environments
• Exposure to DoD, federal, or regulated-sector software environments
• FedRAMP-compliant architecture experience a plus

Company Overview