Senior Software Engineer (.Net Core + LLM's)

Aperia•Dallas, TX

11d•Hybrid

About The Position

Aperia Solutions is a leading payments SaaS company headquartered in Dallas, Texas. We build risk management, residuals accounting, compliance, and analytics platforms used by merchant banks, ISOs, payment processors, and other participants in the credit card payments ecosystem. Operating under PCI DSS 4.0 compliance across dual on-premises datacenters (Allen, TX and Chicago, IL) plus Azure cloud, we process high-volume payment data for some of the industry’s largest players. We’re in the middle of a significant platform modernization program: a next-generation risk analysis and scoring platform on Microsoft Fabric, an AI-powered ingestion platform, new AI-native applications, and ongoing evolution of the products our clients rely on every day. The teams executing this work are deliberately small and senior, with executive-level support and minimal bureaucracy. Every senior hire is a founding contributor to the architecture and the code. Aperia is hiring a mid-senior level software engineer to join the team building our next-generation risk analysis and scoring platform, with opportunities to contribute across our wider product portfolio — the AI-powered ingestion platform, residuals and compliance products, and client-facing web applications. You’ll work under the technical direction of our Lead Software Engineer, alongside a Senior Data Platform Engineer and a Senior DevOps engineer, with big-picture system design owned by dedicated architects. It’s a deliberately small, senior-leaning team — which means real features, real code review, and real growth, not ticket-grinding. Day to day, you’ll build production C#/.NET services and REST APIs, develop React frontends for client-facing applications, and contribute to our Python-based agentic work as you grow into it. This is a role for an engineer with a few strong years behind them who wants to level up fast: you’ll get direct mentorship from senior engineers, exposure to a modern Azure/Kubernetes platform, and a team culture that treats AI-assisted development as a first-class skill.

Requirements

3–5 years of professional software engineering experience shipping production systems.
Solid C#/.NET skills — ASP.NET Core, REST API design, and comfort working in an established service architecture.
Working proficiency in TypeScript and React, with production frontend experience.
Relational database fundamentals — schema design, sensible queries, and an understanding of transactions.
A habit of testing your own work — you write meaningful tests without being asked and treat code review as part of the craft.
Clear written and verbal communication — you can explain a technical decision, ask good questions, and take feedback well.
Comfort working in a cloud environment — you can follow a deployment through a CI/CD pipeline and debug what’s yours, even if you don’t own the infrastructure.
Genuine enthusiasm for AI-assisted and AI-native development. You don’t need LLM production experience, but you should be curious, current, and eager to build with these tools.

Nice To Haves

Exposure to building with LLMs — LangGraph/LangChain, RAG, prompt engineering, or even serious personal projects. We’d rather see curiosity and momentum here than years of experience.
Python proficiency beyond scripting.
Hands-on Azure experience — AKS/Kubernetes, App Services, or Azure DevOps administration.
Payments or financial services background; any exposure to PCI-scoped systems.
Familiarity with messaging patterns (Azure Service Bus, Event Hubs, Kafka) or observability tooling (OpenTelemetry, Application Insights).
OAuth2/OIDC or other identity standards experience.

Responsibilities

Build and ship production C#/.NET services and REST APIs serving high-volume payment data under PCI DSS constraints.
Develop client-facing web application features in React and TypeScript, from component work through API integration.
Own well-scoped features end to end on the risk platform build — design discussion, implementation, code review, testing, and deployment.
Contribute to our LangGraph-based agentic application — tool integrations, tests, and evals — growing your Python and LLM-engineering skills along the way.
Write automated tests (unit, integration, end-to-end) as part of everyday development, and participate actively in code review — giving feedback, not just receiving it.
Ship through Azure DevOps CI/CD pipelines to AKS, with support from the team’s DevOps engineer.
Use AI-assisted development tools (Claude Code, Cursor, GitHub Copilot) as a core part of your workflow, following documented team standards.
Pair with senior engineers and participate in design reviews, growing toward ownership of larger workstreams across the portfolio.