PWPuck WangSoftware developer

Full-stack software developer · Ottawa, Canada

Hi, I'm Puck.
I build software for complex work.

Full-stack software engineer based in Ottawa, focused on Java/Spring Boot and building reliable systems with Docker, Redis, MySQL, and event-driven architectures.

View resume wzlpuck@gmail.com

02 / Writing

Ideas in progress.

All posts
01
Sep 29, 20262 min read

Semantic Caching: Caching for LLM Apps

Faster LLM responses

AgenticSoftware
02
Aug 3, 20265 min read

The Yen, Carry Trades, and the July 30 Nasdaq Selloff

ersonal observations on a sharp Nasdaq move, yen volatility, official intervention, and the yen carry trade.

Stock MarketFinanceInvestment
03
Apr 18, 20264 min read

Fundamentals of Building AI Agents: ReAct with LangChain

A practical note on what AI agents are, how the ReAct loop works, and how to build a small LangChain SQL agent with runtime context and checkpoints.

AgenticLangChainReAct
04
Apr 8, 20265 min read

How to Create a Postgres Replica

How PostgreSQL streaming replication works and a small Docker demo for bringing up a read replica

DatabaseInfra
05
Feb 8, 20261 min read

Interview Preparation(Python) Part One

Notes about Python language best practice and easy-to-make mistakes

PythonInterviewSoftware
06
Jan 26, 20262 min read

About Myself

Background, interests, and a quick walk through my education, experience, and core technical focus.

AboutCareerSoftware
07
Oct 28, 20255 min read

It is always us-east-1

A collective summary of the AWS outage in October 19, 2025.

AWSIntraOutage

03 / Projects

Selected work.

All projects
01

Happy Holiday Icon

GitHub

Cloud-native image generation application that transforms uploaded images into holiday-themed icons through an asynchronous, event-driven AWS processing pipeline.

Stack

Next.jsTypeScriptAWS LambdaAmazon S3Amazon SQSDynamoDBTerraformSharp

Details

  • Designed an event-driven image processing pipeline with S3, SQS, Lambda, and DynamoDB for asynchronous job orchestration
  • Implemented fault-tolerant processing with conditional state transitions, processing leases, and automated retry recovery
  • Added secure presigned uploads, authentication, rate limiting, prompt-injection safeguards, and CI/CD with Terraform and GitHub Actions
02

Wealth Hub Agent

GitHub

Hierarchical multi-agent system that orchestrates end-to-end financial research, analysis, and decision workflows, with real-time streaming to a web dashboard.

Stack

FastAPIAsyncioNext.jsServer-Sent EventsLlamaIndexChromaDBModel Context Protocol (MCP)

Details

  • Improved research throughput by 40% via parallel execution of independent agent tasks
  • Standardized tool-calling with MCP for reliable integration with financial data providers
  • Implemented RAG over SEC filings and financial news for semantic search and grounding
03

LLM-based YouTube Summarizer

GitHub

Microservice-based application that generates structured summaries for YouTube videos, including an automated captioning pipeline for videos without subtitles.

Stack

Spring BootSpring AIgRPCAWS LambdaWhisper

Details

  • Reduced service latency from 500 ms to 100 ms by adopting gRPC
  • Decreased payload size by 30% while improving response performance
  • Built a Whisper-powered Lambda pipeline to generate captions when subtitles are missing