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

Aperia•Dallas, TX

10d•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. This is a hands-on technical leadership role spanning the breadth of Aperia’s product portfolio: the risk platform build, the AI-powered ingestion platform, our residuals and compliance products, client-facing web applications, and a new LangGraph-based agentic application. You’ll report directly to the SVP of Research & Development and act as the connective tissue across these workstreams — leading implementation, driving code-level design decisions, and reviewing designs and code across teams. This is not a people-management position, and you won’t be working alone at the whiteboard — Aperia has dedicated architects who own the big-picture system design. Your job is to turn that design into shipped, production-quality software and to set the engineering standard for how it gets built. You’ll lead the risk platform build team — a Senior Data Platform Engineer, a Senior DevOps engineer, and a mid-level developer — while spending most of your time in the code yourself: shipping production C#/.NET services, building React frontends, and contributing to our Python-based agentic work. You lead by technical judgment and example, working closely with our architects where workstreams meet.

Requirements

8+ years of professional software engineering experience, including 2+ years as a tech lead or equivalent — setting direction for other engineers, not just yourself.
Expert-level C#/.NET — ASP.NET Core, REST API design, microservices patterns, and the judgment to know when not to use them.
Strong TypeScript/JavaScript skills with production React experience.
Solid Azure and Kubernetes (AKS) experience — containers, deployment patterns, and CI/CD with Azure DevOps.
Strong relational database skills — schema design, query performance tuning, and transactional correctness on OLTP workloads, with the SQL fluency to work comfortably against analytical endpoints in the Fabric estate.
Distributed-systems fundamentals: API design, idempotency, failure modes, and data consistency across service boundaries.
A demonstrated ability to raise a team’s engineering bar — through code review, testing discipline, and clear written technical design.
Genuine enthusiasm for AI-assisted and AI-native development. You don’t need to have shipped an LLM product, but you need to be curious, current, and unafraid of the tooling shift.

Nice To Haves

Hands-on experience building LLM-powered or agentic applications — LangGraph/LangChain, RAG pipelines, agent orchestration, vector search, LLM evaluation, or MCP-based tool integration. Strongly preferred.
Python proficiency — recommended, given our agentic and ingestion work.
Payments or financial services domain background; PCI-scoped system experience.
Messaging and eventing patterns — Azure Service Bus, Event Hubs, or Kafka.
Observability practice — OpenTelemetry, Application Insights, Grafana/Prometheus.
Identity standards — OAuth2/OIDC, Microsoft Entra ID.
Familiarity with our adjacent stack: Airflow, Kogito/DMN, OpenBao, Terraform.
Awareness of Microsoft Fabric / Delta Lake concepts (you won’t own the data platform, but you’ll integrate with it).

Responsibilities

Lead implementation across multiple concurrent projects — translate architecture from our dedicated architects into technical plans, code-level designs, and shipped software.
Design and ship production C#/.NET services and REST APIs serving high-volume payment data under PCI DSS constraints.
Build and evolve client-facing web applications in React and TypeScript, from component architecture through API integration.
Contribute hands-on to our LangGraph-based agentic application — agent orchestration, tool integration, and the engineering discipline (testing, evals, observability) that makes LLM-powered systems production-worthy.
Own engineering standards across teams: code review culture, automated testing discipline (unit, integration, end-to-end), and CI/CD practices in Azure DevOps.
Deploy and operate services on AKS across Azure and our dual on-premises datacenters, partnering with DevOps on infrastructure and release engineering.
Mentor the engineers on your team — data platform, DevOps, and application developers — through code review, pairing, and design collaboration.
Champion AI-assisted development (Claude Code, Cursor, GitHub Copilot) — help define, document, and enforce team standards for using these tools well.
Participate in design reviews and ADR discussions with the architecture team, bringing an implementer’s perspective.
Guide your team’s data platform work at the integration boundaries between application workstreams and the Microsoft Fabric data estate.