Jun 1
When Prompt Engineering Hits a Ceiling
For the last two weeks I've been stuck on the same bug in ResumeMatch. The resume rewrite pass was producing edits that looked plausible at first gla...
7 min read
Writing
Notes on systems, LLMs, and the industry building them.
I'm Wenhao, a software engineer. I write up system design problems I've worked through, what I'm learning about LLMs, notes from shipping side projects like ResumeMatch, and the occasional take on layoffs and where the industry is heading.
22 postsSince 2025
Mar 30
Adding a DynamoDB Caching Layer to a Serverless LLM Pipeline
Another late night on Sunday shipping features. This week I added a caching layer to ResumeMatch that drops duplicate analysis latency from 25 second...
8 min read
Mar 21
How I Fixed False Negative Keyword Matching in My LLM-Powered Resume Analyzer
Happy Friday! Weekend's almost here, but before I sign off, I wanted to write up a fix I shipped this week for ResumeMatch. A user in the accounting ...
10 min read
Mar 14
Debugging CORS and Rate Limiting in a Serverless App
Happy Saturday! Or at least it was supposed to be. Two hours ago I cracked open ResumeMatch to check something quick and walked straight into a blan...
6 min read
Feb 9
New Year, New Certification
It’s 2026, and it’s been a while since I last published a blog post. Today feels like a good reason to break that silence. I’m happy to share that I’...
5 min read