Senior Full-Stack Software Engineer

Ontrac Solutions • Chicago, IL

6d

About The Position

Ontrac Solutions is seeking an experienced Senior Full-Stack Software Engineer to support a critical customer engagement. This role suits an engineer who is equally at home across the stack and who can work through an established codebase with confidence — understanding how existing features behave before extending, refactoring, or retiring them. You will build and extend full-stack features across React frontends and Node.js and Go backend services, design and query both PostgreSQL and MongoDB, and implement authentication, role-based access control, and authorization across the services in scope. You will work closely with our program manager and engagement leads, together with customer stakeholders, to keep work moving cleanly from initial definition through to final delivery. This is a role for someone comfortable in someone else's codebase. A substantial part of the work is establishing how current functionality operates, then refactoring or decommissioning legacy components — without regressing behaviour already in place.

Requirements

• 5+ years of professional software engineering experience spanning frontend and backend work.
• Bachelor's degree in Computer Science or a related field, or equivalent practical experience.
• JavaScript and TypeScript — building type-safe applications and services end to end.
• React — dynamic, responsive, real-time frontend interfaces.
• Node.js — scalable server-side applications and asynchronous backend services.
• Go — scalable backend services and APIs.
• Relational and NoSQL datastores — specifically PostgreSQL and MongoDB, including schema design and querying.
• Secure authentication and authorization, including role-based access control.
• Building, modifying, and integrating scalable backend APIs.
• Unit and integration testing for backend components.
• Comfort navigating complex codebases to refactor or decommission legacy code without regressing existing behaviour.
• Working knowledge of AWS cloud services and the associated client libraries and APIs.
• Delivery within an Agile/Scrum team, including sprints, stand-ups, and retrospectives.

Nice To Haves

• Snowflake — integrating and querying enterprise cloud data warehousing.
• n8n — building and maintaining automated workflow integrations.

Responsibilities

• Build and extend full-stack features across React frontends and Node.js and Go backend services, in line with agreed designs and acceptance criteria.
• Build, modify, and integrate scalable backend APIs across the services in scope.
• Work through the existing codebase to establish how current functionality operates, then refactor or decommission legacy components as directed, without regressing behaviour already in place.
• Design and query PostgreSQL and MongoDB schemas in support of new and modified features.
• Implement and maintain authentication, role-based access control, and authorization across the services in scope.
• Write unit and integration tests covering the components delivered, to the agreed coverage expectations.
• Integrate with AWS services and, where the engagement calls for it, Snowflake and n8n.
• Take part in sprint ceremonies and working sessions with Ontrac and customer teams, and keep delivery status current so progress can be tracked against agreed measures.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior