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Senior Software Engineer, Payroll Engine

de anda capitalPlano, TX

2 days ago

Occupations

Software DevelopersPayroll and Timekeeping ClerksComputer Programmers

Industries

Custom Computer Programming ServicesSoftware PublishersComputer Systems Design Services

$100,000–$105,000

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About the role

Senior Software Engineer, Payroll Enginede Anda portfolio companyTeam: PayrollLevel: Senior (IC)
Location: Remote (U.S.)Start: early November 2026
Compensation: $100,000–$105,000THE ROLEYou own the heart of the product: the payroll domain model, the append-only ledger, and the pay-run engine that takes a run from draft to committed check. Your code decides what people get paid. The exit criterion for your first four months is that the engine reproduces a corpus of real pay runs from the incumbent system to the cent.
WHAT YOU WILL DO:
  • Design and build the domain model: pay groups and calendars, earning and deduction codes with limits and ordering, employee tax profiles, year-to-date and quarter-to-date accumulators per EIN.
  • Build the ledger as an append-only record of every committed check and adjustment, the single source for registers, general ledger, year-end and audit.
  • Build the pay-run state machine: draft, preview, calculate, approve, commit; regular and off-cycle runs; manual checks; voids and reversals; retroactive pay.
  • Implement gross-to-net orchestration around the tax adapter: pre-tax and post-tax deductions, imputed income, supplemental wages, garnishment calculation with withholding limits.
  • Build the generic hours-and-earnings import, then the bridge from the portfolio company's time-and-attendance product that turns locked, approved timecards into earnings lines with rate, pay code, work location and job-cost dimensions.
  • Build and maintain the regression harness: replay the corpus on every change, report variances to the cent, and run every variance to ground.
  • Write Technical Documents from the product manager's PRDs, direct coding agents against them, and review every agent-authored PR line by line before merge.
  • Keep money as integer cents and committed runs immutable; make every calculation re-runnable from stored inputs and engine version. MUST HAVE
  • 5+ years building transactional backend systems in Python; Django and PostgreSQL in production.
  • Has shipped a system where money is the output: payroll, billing, banking, insurance claims, accounting. You can explain how you kept a ledger correct under concurrency and corrections.
  • Fluent in integer-cents arithmetic, rounding rules, and the difference between a correction and a reversal.
  • Designs state machines and event-sourced or append-only data models; knows why committed records are never edited.
  • PostgreSQL depth: migrations against live data, constraints, transactions, advisory locks or equivalent.
  • Writes tests as part of the change; has built or maintained a replay or golden-file regression suite.
  • Has worked with AI coding agents on real deliverables: writes specs an agent can execute and reviews agent output critically.
  • Comfortable in a monorepo with CI, Docker Compose and GitHub Actions.
NICE TO HAVE:
  • U.S. payroll domain: pay codes, pre/post-tax ordering, YTD limits, FLSA overtime, garnishment priority rules, multi-EIN employers.
  • GraphQL schema design (Graphene) and React/Apollo for the pay-run UI.
  • Celery or equivalent for long-running calculation jobs.
  • Time and attendance or scheduling domain; job costing and labor allocation.
  • Experience maintaining AGENTS.md-style conventions for a team. NOT A FIT
  • CRUD-app backgrounds with no financial or transactional system experience.
  • Engineers who treat floating-point money as fine until it isn't.
  • Someone who treats agent output as done once it compiles.
  • Someone who wants a green-field stack; this lives inside the portfolio company's existing time-and-attendance codebase.

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JOB OVERVIEW

Salary

$100,000–$105,000

Experience level

Lead

Location

Plano, TX

Occupation

Software Developers

Industry

Custom Computer Programming Services

Posted

2 days ago

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