John Aquino

John Aquino

AI Systems Engineer | LLM Architectures | Cloud-Native Applications

6+ years of professional experience building cloud and AI-powered software systems.

Software engineer at Vanguard building modern AI systems and cloud applications. I specialize in LLM architectures, agentic software, and scalable backend infrastructure—primarily using Python and AWS. I've also released multiple mobile apps, combining engineering, product design, and entrepreneurship to create intelligent software.

AI Systems Work

Multi-agent orchestration
Retrieval-augmented generation (RAG)
Tool-use agents
LLM reasoning chains

Projects

Shipped multiple production mobile applications used by real users across iOS and Android.

Career Timeline

Application Engineer III

Vanguard

Mar 2025 - Present
AI/LLMsRAGLangChainAWS BedrockObservability
  • Engineered Python-based AI service infrastructure on AWS to support scalable agent workflows, integrating Bedrock models, retrieval pipelines, and internal APIs into production-ready systems.
  • Built core components of a multi-agent AI system using LangChain and AWS Bedrock to orchestrate agents that gather, synthesize, and analyze enterprise data.— Reduced research turnaround time by up to 3 weeks
  • Implemented RAG pipelines using Pinecone and Neptune GraphRAG to provide grounded, context-aware responses from internal knowledge bases and document stores.
  • Designed the agent orchestration layer with tool-use patterns, enabling agents to query internal APIs, parse documents, and chain reasoning steps.— Autonomously answering complex business questions
  • Shipped AI-powered call center bots that automated customer support workflows and reduced live-agent call volume.
  • Built production support observability dashboards for real-time system health monitoring and faster incident triage.

Application Engineer II

Vanguard

Mar 2023 - Mar 2025
AngularSpring BootAWSPythonSplunk
  • Designed and developed web applications using Angular, Python Lambdas, and Spring Boot for backend services and customer-facing workflows.
  • Migrated legacy mainframe data to AWS cloud infrastructure serving users holding over $1 trillion in assets.
  • Modernized call center infrastructure, reducing agent call volume and lowering operational costs.
  • Acted as Site Reliability Champion, leading system availability, performance monitoring, and incident response.
  • Mentored junior engineers, fostering professional growth and improving team productivity.
  • Developed and demoed an AWS Bedrock Generative UI POC to leadership.— Led directly to production AI products built from the initial POC

Application Engineer I

Vanguard

Jun 2020 - Mar 2023
AngularREST APIsResponsive Design
  • Built a high-value transactions web application with enhanced security and reliability for Vanguard's institutional and retail clients.
  • Led delivery of the mobile-responsive Angular experience for the transactions platform.— Enabled secure high-value transactions from mobile browsers across iOS and Android

Technical Skills

Primary Languages

Python (primary)JavaTypeScript/JavaScriptDart

AI & Data

PineconeNeptune (GraphRAG)Bedrock

Frameworks & Libraries

LangChainSpring BootAngularNext.jsReactFlutter

Cloud & DevOps

LambdaECSAPI GatewayDynamoDBS3CognitoEC2Step FunctionsSQSSNSCloudWatchCloudFormationCI/CD

Monitoring & Logging

SentrySplunkAWS CloudWatch

Certifications

Jan 2025

AWS Certified AI Practitioner

Foundational knowledge in machine learning and AI on AWS.

Dec 2022

AWS Certified Developer - Associate

Expertise in deploying, debugging, and developing on AWS.

Aug 2022

AWS Certified Cloud Practitioner

Foundational cloud concepts, AWS services, security, and pricing.

Education

University of Georgia

2016-2020

B.S. in Computer Science

Relevant Coursework: Cyber Security, Linear Algebra, Evolutionary Computation