Hollen Graver | Senior Software Developer & Tech Lead

Overview

Summary

Senior Software Developer and Tech Lead with over a decade of experience designing and scaling distributed systems, cloud platforms, and developer tooling across Java, TypeScript, Go, and C#. Proven record leading high-impact initiatives from multi-service transaction workflows and fraud mitigation to full-stack cloud migrations. Passionate about software architecture, engineering mentorship, and agentic AI systems.

Career History

Experience

Campspot

Hospitality • SaaS • High Scale

March 2019 – Present

Senior Software Developer Level 2

Mar 2024 – Present

Tech Lead Java Kotlin Distributed Systems Flutter AWS

Served as Tech Lead for the architecture and delivery of an 'Abandoned Cart' recovery platform, orchestrating event-driven cross-domain workflows across distributed services to automate customer re-engagement—recovering tens of thousands of dollars in cart value in the first month alone.
Engineered automated fraud mitigation defenses that eliminated distributed carding attacks, safeguarding payment gateways and protecting revenue across tens of thousands of daily booking sessions.
Hired, onboarded, and mentored junior and mid-level developers through system architecture guidance and code reviews, directly elevating engineering velocity and facilitating promotions to senior levels.
Developed and maintained Campspot's customer-facing mobile application using Flutter (iOS & Android), supporting tens of thousands of monthly active users with campsite search, booking, and reservation management.

Senior Software Developer Level 1

Apr 2022 – Mar 2024

Gift Cards Payments ($2M–$5M/day) POS & Invoicing Angular

Architected and launched an enterprise gift card platform adopted across hundreds of campground clients, establishing a new recurring revenue channel and expanding consumer booking flexibility.
Hardened and optimized mission-critical checkout and payment processing pipelines, processing $2M–$5M in daily transactions with high availability.
Engineered in-house Point of Sale (POS) and invoicing systems essential to daily on-premise operations across partner parks.
Spearheaded UX and checkout improvements that reduced purchase friction, contributing to a measurable increase in Net Promoter Score (NPS) and customer retention.

Software Developer Level 2

Jul 2019 – Apr 2022

Java Migration Pricing Engines Elasticsearch PostgreSQL

Owned the implementation of enterprise discount and promotional pricing engines operating reliably across multi-tenant park environments.
Contributed to the multi-phase backend migration from a legacy Node.js/TypeScript stack to modern Java microservices, increasing throughput and type safety.
Optimized search and reservation data workflows across Elasticsearch and PostgreSQL to support peak seasonal booking surges.

PRSM Healthcare

Healthcare Operations • Infrastructure

June 2014 – May 2019

Software Engineer

Jun 2014 – May 2019

C# ASP.NET Fault Tolerance Azure & AWS Migration VoIP / FreePBX

Engineered a fault-tolerant system using redundant VPN connections and load balancing to ensure 100% uptime for mission-critical call center infrastructure.
Facilitated a 2x increase in client capacity by developing scalable web applications and data processing pipelines while maintaining operational stability.
Led the end-to-end rewrite of the core B2B business application, migrating legacy PHP to C# ASP.NET with improved security and modularity.
Orchestrated the migration of business applications from on-premises infrastructure to Microsoft Azure and subsequently to AWS, modernizing deployment pipelines.
Integrated customer outreach platforms with FreePBX VoIP infrastructure to automate calling workflows and improve connection rates.

Engineering Work

Technical Projects

Agentic AI & Local LLM Tooling

Autonomous Workflows, Inference Bridging & Model Context Protocol

Model Context Protocol (MCP) Llama.cpp Claude Code / OpenCode Python Go

Architected multi-agent coding workflows using local LLM inference engines (Llama.cpp) and autonomous agent harnesses (OpenCode, Claude Code), overcoming context window constraints to accelerate development velocity and code quality.
Engineered custom Model Context Protocol (MCP) servers and LLM agents to equip models with real-time runtime inspection and secure external tool calling capabilities.
Developed lightweight Python and Go network proxies and inference microservices, including OpenAI-compatible bridging for local model servers and self-improving agent frameworks.

Expertise

Technical Skills

Languages

Java Kotlin TypeScript JavaScript Go Python C# Dart SQL

Frameworks

Angular AngularJS Flutter .NET Core ASP.NET Quarkus Dropwizard

Data & Search

PostgreSQL MySQL SQLite Elasticsearch OpenSearch Redis Valkey

DevOps & Infra

AWS Docker Kubernetes (K3s) ArgoCD Linux Prometheus Grafana CI/CD

Core Engineering

Distributed Systems Fault-Tolerant Design REST APIs TDD Clean Architecture Technical Mentorship

AI & Agentic Systems

Model Context Protocol (MCP) LLM Agents Llama.cpp Local Inference Tool Calling Prompt Engineering

Academic Background

Education

Mansfield University of Pennsylvania

B.Sc. in Computer Information Science: Information Systems

Graduated 2014