Wenhao HeBlog
Writing24 posts · Since 2025

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.

Pinned
  1. My resume tool won't rewrite your resume, and that's the feature
  2. Adding a DynamoDB Caching Layer to a Serverless LLM Pipeline
  3. How I Fixed False Negative Keyword Matching in My LLM-Powered Resume Analyzer
  4. When Prompt Engineering Hits a Ceiling
Tagged6 posts
Aug 1
From RNNs to TransformersAug 1 · 4 min read

As previously mentioned, input data for a neural network must first be transformed into word embeddings.

4 min read
Jul 31
From Word Embeddings to RNNsJul 31 · 4 min read

Given a couple of words, can we generate the next word? Or, given a sentence, can we determine whether each word expresses a positive or negative…

4 min read
Jul 30
From Matrices to CNNsJul 30 · 3 min read

In the previous sections, we saw how matrix operations can be used to calculate neural outputs using linear transformations followed by nonlinear…

3 min read
Jul 27
Tuning Neural NetworksJul 27 · 3 min read

The essence of neural networks lies in progressively applying activation functions to linear transformations.

3 min read
Jul 26
Calculating Neural Network ParametersJul 26 · 3 min read

Let's start with a simple linear function: y = wx + b Q: What's a good w and b?

3 min read
Jul 25
From Functions to Neural NetworksJul 25 · 5 min read

What if I told you that everything we know about the world - every rule, every pattern, every piece of logic - can be described by functions?

5 min read
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