Open to Senior, Staff & Lead Backend Roles

Nick Willard

Senior Backend Engineer · Payments & Financial Systems

I build the systems money moves through. 11+ years at Mastercard, Discover (now Capital One), and Clearent, architecting billing, settlement, and 3D Secure platforms, and leading teams that ship 3x faster with AI.

Download Resume LinkedIn

Remote, or hybrid within 70 mi of Rockford, IL  ·  Java · Spring Boot · C#/.NET · AWS

Shipped at Capital One Discover Mastercard Equifax Clearent Ungerboeck
30M
Monthly Transactions
Billing DB I architected
3x
Per-Engineer Velocity
12–15 → 45–50 pts / sprint
<30m
PR Cycle Time
Down from multi-hour queues
50%+
DB Licensing Cost Cut
Oracle → PostgreSQL
10
Engineers Led
As technical lead
11+
Years in Fintech
Payments · card · credit
01 · Selected Work

Proof, not adjectives.

Four systems that show how I work: own the problem end to end, design for failure, and measure the result.

Discover (now Capital One) 30M txns / month

Billing Platform Foundation

Problem
Cardmember paid-benefit fees needed a production billing system that could settle and reconcile reliably against the core card platform.
Built
Architected the billing database end to end: schema, cluster provisioning, partitioning, Flyway migrations, security groups. Wired settlement and reconciliation through a service wrapper over the card platform.
Result
Roughly 30M transactions a month. Failure-mode playbooks made incident response self-service for the whole team.
Java · Spring Boot · AWS · Flyway · Splunk
Mastercard +30% throughput

3D Secure: Monolith to CQRS Microservices

Problem
A high-availability 3DS authentication monolith handling millions of global requests could not be deployed or scaled piece by piece.
Built
Led the decomposition into Spring Boot microservices. Designed command and query services on the Axon Framework with async event handlers, plus replay paths so failed transactions recover without data loss.
Result
Independent deploys, 30% more throughput, and an Oracle to PostgreSQL migration that cut licensing costs by over 50%.
Java · Axon · CQRS · Redis · PostgreSQL
Discover (now Capital One) 3x per engineer

Team-Wide AI Engineering System

Problem
Engineers on a 10-person team averaged 12 to 15 points each per sprint, with PRs waiting hours for review.
Built
A Claude Code workflow with custom team skills and automated weekly coverage-report pipelines, backed by standard PR templates and pre-commit hooks.
Result
Each engineer now delivers 45 to 50 points a sprint, and PR cycle time is under 30 minutes. Quality held because the guardrails shipped with the speed.
Claude Code · Jenkins · Docker · Coverage automation
Mastercard · Clearent · Discover Daily settlement cycles

Money Movement, Start to Finish

Settlement
Built C#/.NET settlement services and batch jobs moving transaction and funding data through daily cycles for a merchant payment processor.
Security
Worked inside PCI DSS scope with HSM-backed key management and tokenized datasets. Built merchant boarding workflows that replaced manual onboarding.
Reliability
On-call for 3DS auth services. Authored division-wide postmortems and circuit-breaker refactors that turned brittle batch boundaries into observable services.
C#/.NET · SQL Server · PCI DSS · HSM · Tokenization
Independent · Production system, not a demo ~$1 per user / month

AI Training Coach: Serverless LLM Platform

Strava Coros EventBridge Lambda Bedrock SES → Briefing HRV · sleep · pace

Ingests live Strava activity and Coros biometrics (HRV, sleep, resting HR), computes TRIMP training load (CTL/ATL/TSB), and emails a personalized daily briefing written by Claude. Terraform via GitHub Actions OIDC with no long-lived CI credentials. One Cognito-backed API serves a React SPA and a React Native app.

“All numeric reasoning and anomaly detection runs in Python before the prompt is built, so the model only sees validated, typed inputs. Compute first, generate second.”

AWS Lambda · EventBridge · Bedrock · SES · Cognito · Terraform · React Native
View on GitHub →
02 · Recommendations

From the people I've shipped with

“He significantly contributed to billing module establishing production-grade database foundations and comprehensive, well-documented playbooks that enabled full self-service within his team.”
Kirthi Paruchuri Technology Leader · managed Nick at Capital One
“His technical depth across backend development, database architecture (Aurora PostgreSQL), and microservice resilience patterns (circuit breakers, exponential backoff, OTEL) is top-tier.”
Mark Sage Senior Engineer · same team at Capital One
“A thoughtful critical thinker with a strong commitment to application quality, reliability, and observability.”
Rommel Aguilar Senior Manager, Software Engineering · managed Nick at Capital One
“You can be confident that Nick will sink his teeth into his objective and drive it to completion.”
Zachary Fransen VP, Data & Analytics at Branch · managed Nick at Clearent
Read all recommendations on LinkedIn →
03 · Experience

Career Timeline

Discover Financial Services (now Capital One) Jul 2024 – Present
Team Lead / Application Engineer Java · Spring Boot · AWS · Docker
  • Billing Platform Foundation: Architected the production billing database for cardmember paid-benefit fees, processing roughly 30 million transactions per month. Integrated settlement and reconciliation through a service wrapper over the core card platform.
  • Technical Leadership: Technical lead for a team of 10 engineers, running code reviews, pairing daily, and onboarding with structured check-ins. Mentored an engineer into the team lead role.
  • AI Engineering System: Built a team-wide Claude Code workflow that scaled each engineer's sprint velocity from 12–15 to 45–50 points (roughly 3x) and cut PR cycle time to under 30 minutes.
  • Observability & Release Velocity: Distributed tracing across all billing services in Splunk. Automated Jenkins and Docker pipelines moved releases from bi-weekly to daily, cutting manual toil by roughly 45%.
  • Resilience Engineering: Circuit-breaker patterns and live dependency tests turned a brittle batch boundary into a fault-tolerant, observable service.
Mastercard Dec 2021 – Jul 2024
Senior Software Engineer Oct 2022 – Jul 2024 Java · Spring Boot · Microservices · Axon Framework · Redis · PostgreSQL
  • Monolith Decomposition: Architected the breakup of a high-availability 3D Secure monolith into modular Spring Boot microservices serving millions of global authentication requests.
  • CQRS & Event-Driven Architecture: Designed command and query services on the Axon Framework with async event handlers and replay/reprocessing paths, so failed transactions recover without data loss. Throughput up 30%.
  • Database Migration: Led Oracle to PostgreSQL migration, cutting licensing costs by over 50% and improving query performance 20–35% with Redis caching.
  • Test Reliability & Incident Response: Raised coverage to 90%+ with JUnit and Mockito, reducing production defects by roughly 25%. On-call for 3DS services and authored division-wide postmortems.
Senior BizOps Engineer Dec 2021 – Oct 2022
  • Global Data Pipelines: Designed and operated multi-region Apache NiFi ETL pipelines routing terabytes of business-critical data. Automated deployments cut migration-related incidents by 40%.
Ungerboeck Software International Nov 2018 – Nov 2021
Software Engineer II C# · .NET Core · Azure · SQL Server · PowerShell
  • Platform & Integration Engineering: C#/.NET services and nightly Salesforce, Jira, and Zendesk integrations that eliminated recurring manual work for 50+ stakeholders.
  • .NET Core Migration: Led the move from .NET Framework to .NET Core, setting the upgrade path for platform services.
  • Azure & Developer Automation: Azure Functions on Azure SQL with Key Vault secrets and Azure DevOps pipelines. PowerShell and Chocolatey tooling cut onboarding from 4+ hours to under 30 minutes.
Clearent Apr 2015 – Dec 2017
Software Engineer C# · .NET · SQL Server · Salesforce
  • Payment Settlement: Built and maintained settlement services and batch jobs for a merchant payment processor, moving transaction and funding data through daily settlement cycles.
  • Merchant Boarding & PCI: Automated merchant onboarding in C# and Salesforce. Worked within PCI DSS scope with HSM-backed key management and tokenized datasets.
DevOps Engineer Equifax Dec 2017 – Nov 2018

Azure DevOps and Jenkins pipeline automation, plus C# tooling for multi-state regulatory reporting.

04 · About

Built for the long haul

Nick Willard running through a creek crossing during the Leadville 100 Trail Run

Twin Lakes, CO, en route to Hope Pass, Leadville 100 Trail Run, 2025.

I've spent more than a decade inside payment and financial systems: settling merchant funds at Clearent, securing 3D Secure authentication at Mastercard, and building the billing platform behind roughly 30 million monthly transactions at Discover. I like the high-stakes backend work, where a bug means someone's money is wrong.

Lately I've been proving that AI makes good teams faster without making them sloppier. I built the Claude Code workflow my team of 10 runs on, and I invest in people through daily pairing and real code review. One engineer I mentored now leads a team.

Off the clock I run ultramarathons, including the Leadville 100. The habits carry over: steady pacing, obsessive preparation, and a plan for when things go sideways.

Domain Settlement & reconciliation · card billing · 3D Secure · merchant boarding · PCI DSS
Leadership Tech lead for 10 engineers · mentored a future team lead · postmortem author
Stack Java/Spring Boot · C#/.NET Core · AWS · Azure · Terraform
Education Rasmussen University · A.S. Software Application Development / CS
05 · Skills

Technical Toolkit

Languages

Java C# / .NET Go Python SQL PowerShell Bash

Backend & Architecture

Spring Boot .NET Core Spring Batch Axon Framework CQRS Event-Driven Architecture Domain-Driven Design Microservices REST APIs Node.js Angular

Payments & Security

Settlement & Reconciliation 3D Secure Card Billing Merchant Boarding PCI DSS HSM-Backed Encryption Tokenization

Cloud & Infrastructure

AWS Terraform Lambda · EC2 · S3 · DynamoDB Bedrock · SES · API Gateway · Cognito · EventBridge Azure Functions · Azure SQL · Key Vault · Azure DevOps Docker Jenkins GitHub Actions

Data & Observability

PostgreSQL Splunk SQL Server Oracle Redis Kafka Apache NiFi Databricks Datadog New Relic Dynatrace AppOptics

AI & LLM Engineering

Claude (Anthropic) Claude Code Custom Skills Amazon Bedrock GitHub Copilot Google Gemini Prompt Engineering Compute-First LLM Pipelines
06 · Certifications

Verified Credentials

Terraform Associate (004) HashiCorp
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AI Practitioner Amazon Web Services
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Cloud Practitioner Amazon Web Services
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AZ-900 Azure Fundamentals Microsoft Azure
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DP-900 Data Fundamentals Microsoft Azure
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Certified Administrator Salesforce
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Contact

Hiring for payments, billing, or platform engineering?

I'm looking for a Senior, Staff, or Lead backend role where reliability and money movement matter. If that sounds like your team, a short intro call is the fastest way to find out if we're a fit.

Based in Caledonia, IL. Open to remote, or hybrid within 70 miles of Rockford. Not relocating.

  • Payments & fintech
  • Backend & platform
  • Tech lead track
  • AI-enabled teams
Download Resume (PDF)
linkedin.com/in/nicholas-willard github.com/kwiknick