Application Developer III

The Software Developer III owns delivery of complex features and small systems through production, resolving ambiguous, open-ended problems without hand-holding, within Old National Bank’s Product Engineering organization, and sets the technical direction for their own work. You harden prototypes into resilient, compliant production systems and shape how the team applies AI and agentic delivery to ship secure, reliable software faster., Delivery & engineering execution

• Convert business intent and specifications into shipped features that meet functional, non-functional, and compliance requirements, increasingly using agentic and AI-assisted workflows.
• Write and review high-quality code when establishing patterns, building secure components, integrating services, or ensuring AI-produced code meets standards.
• Ensure both human-written and AI-assisted code is validated through automated testing and continuous verification to maintain safety and correctness.
• Optimize for outcomes: improve cycle time, reliability/SLOs, quality, and delivery economics; apply engineering effort where it provides the most leverage or safety.
• Identify ambiguity, dependencies, and operational risk early; harden prototypes into resilient production systems.
• Follow the bank’s change-management discipline - ship changes to production through documented review and approval, respecting segregation of duties and auditability.

Architecture, platforms & AI systems

• Design and build AI-enabled systems on Amazon Bedrock, and secure them by applying Bedrock Guardrails and prompt designs that defend against prompt injection, prompt leaking, and jailbreaking.
• Design and operate AWS cloud-native / serverless systems using GitOps CI/CD and Terraform.
• Set and document technical patterns for your area, and influence the broader technical direction.

Mentorship & technical influence

• Mentor Developer I and II engineers through pair programming and code-review coaching, in software design, coding best practices, and agentic workflows.
• Lead design and code reviews for your area.
• Partner with product, security, and risk to shape acceptance criteria and appropriate controls, and apply responsible-AI practices (evaluation, guardrails, human-in-the-loop) in a regulated environment.

This is an experienced individual-contributor role, one of three experience levels in our Software Developer family (Levels I, II, and III). You may mentor peers and lead design and code reviews for your area, but people management and org-wide governance belong to separate tracks. Strong engineering fundamentals and the ability to write high-quality software remain essential, even as you increasingly deliver through agentic and AI-assisted workflows., * Bachelor’s degree in Computer Science or a related field, or equivalent practical experience (at this level, a track record of owning production systems carries the most weight).

• 5-8 years of professional software engineering experience, including ownership of complex, production systems.
• Strong proficiency in two or more of Go, Python, and TypeScript, including API design, integration patterns, and cloud-native development.
• Experience with AWS, CI/CD, and infrastructure-as-code (Terraform); familiarity with serverless architectures.
• Demonstrated ability to build secure, reliable systems and to raise the quality bar for a team through reviews and mentorship.

Applied AI / agentic delivery (preferred, grows by level)

• Experience building features that integrate existing AI models - retrieval-augmented generation (RAG), tool/function calling, agent orchestration, evaluations, and guardrails. We build on AWS (Amazon Bedrock, Bedrock Knowledge Bases, Bedrock Guardrails, and AWS-native orchestration such as Step Functions / Lambda); deep experience with a specific framework is not required - we care that you understand the patterns and can apply them in our environment.
• Experience with AI evaluation / observability, guardrails, and policy-as-code.

Preferred

• Experience delivering compliant software in a regulated financial-services environment.

We continually seek highly motivated and talented individuals as our people are critical to our success. In return, we offer competitive compensation with our salary and incentive program, in addition to medical, dental, and vision insurance. 401K, continuing education opportunities and an employee assistance program are also included in our benefit suite. Old National also offers a variety of Impact Network Groups led by team members who are passionate about driving engagement, creating awareness of diverse backgrounds and experiences, and building inclusion across the organization. We offer a unique opportunity to join a growing, community and client-focused company that is firmly rooted in its core values.

Old National Bank has been serving clients and communities since 1834. With over $70 billion in total assets, we are a regional powerhouse deeply rooted in the communities we serve. As a trusted partner, we thrive on helping our clients achieve their goals and dreams, and we are committed to social responsibility and investing in our communities through volunteering and charitable giving.