Software Engineer IV/Tech Lead

Software Engineer IV / Tech Lead

The Software Engineer IV / Tech Lead owns the domain at the heart of AbsenceSoft's leave management platform: eligibility, entitlement, usage, and pay. When state leave, disability, and employer benefits overlap, this role decides how they combine into one correct answer. This is arithmetic that has to be right. It is computed over dates, under laws and employer rules that change on an effective date, and a wrong number means an employee is paid incorrectly or denied leave they are owed.

This is a senior hands-on role with a path to tech lead. You will write production code, shape technical direction for the calculation domain alongside the team's tech leads, and raise the engineers around you, learning the leave-law domain deeply and partnering with Product to turn regulatory requirements into software that holds up in production.

What You’ll Do

• Own the design and implementation of the domain at the heart of our product: eligibility, entitlement, and pay.

• Transform legacy domain services into well-structured, high-performing code on a modern tech stack. Keep today's implementations healthy until it is time to replace them.

• Build agentic workflows for analysis, design, development, testing, and production wellness, and hold what they produce to a standard you can defend.

• Own correctness end to end, from test strategy to how the code behaves in production.

• Raise the bar. Lead design reviews, mentor engineers across teams, and partner with Product and Engineering leadership on the roadmap.

What’ll Set You Up for Success

Required Skills:

• Experience leading design on complex backend systems and guiding other engineers.

• Strong backend engineering in TypeScript/Node.js and C#/.NET: able to maintain a mature .NET codebase and build new domain services on a modern stack.

• Domain-driven design: modeling a complex business domain from first principles, not implementing to spec.

• Has personally owned calculations where correctness is the product (payroll, tax, benefits, insurance claims or eligibility, billing, actuarial, or similar), including rules that change on an effective date, where results already computed under the old rules must stay exactly as they were.

• Daily hands-on use of AI-assisted and agentic development tools, with the habit of verifying their output rather than trusting it.

• Strong automated-testing discipline (NUnit, xUnit, or MSTest), with a clear point of view on how to prove a calculation is right.

• MongoDB or other document-database data modeling, including schema design, aggregation, and indexing at production scale.