Software & AI engineering

DongYeop Lee.

I build things
that listen.

Backend systems, voice agents,
and the tests that keep them honest.

Software Engineering Intern at Hemut / Summer 2026

Explore the work
Expressive ribbon artwork, separate from the recorded waveform below.
Sunview / Call excerpt

Shipment reference muted / Original timing

0:00 / 0:19
Call transcript 0:19 / Redacted excerpt

Agent: Thanks for calling Sunview Logistics. How can I help you today? Caller: Hi, can I check up on a load status? Agent: Yeah, I can do that. What's your load or reference number? Caller: [Load reference muted.] Agent: Alright, one moment. Right, [load reference muted] is delivered.

Automatic transcript, edited to mark redactions. 19-second excerpt. Shipment reference muted; original pace and pauses preserved. The source is a 48 kHz Opus recording.

Measured, not researched.Built, questioned, tested.

A better model.
Or a better question?

I tested speech models on the situations our voice agents actually encounter. A fast transcription isn't much help if it misses the thing a caller needs.

Inside the benchmark

Speech, under
real constraints.

40 synthesized domain clips; a 7-clip name subset for keyterms

Public harness
Release pending
0.030.040.050.0602505007501000 msWERMedian latency01020304
Parakeet TDT 0.6B v3170 ms / 0.047 WER

Three reported baselines; one keyterm projection. Local and hosted runtimes differ.

Method & limits

Historical reported summary from open-weight-stt-findings.md, not a fresh run. WER is a fraction; latency is the reported median in milliseconds. Whisper and Parakeet ran locally on an M4 GPU; Deepgram used a hosted API, so timing includes different compute and network conditions, not live-turn latency. The keyterm row is the same Deepgram system: full-corpus WER is projected from seven name clips, and 204 ms is inherited from the baseline, not remeasured. The separate 240-row probe pools six audio conditions and is not this 8 kHz summary.

Selected work / 05

Production systems.
Independent experiments.

Built on my own terms.

Veracity

A Chrome extension that checks article claims against sources and places the results beside the text.

I chose Perplexity because I preferred its search at the time. Bring your own key kept me from taking on ongoing API bills, and the extension did not need a backend of my own.

Engineering by DongYeop Lee.Chrome Web Store

EcoPrompt

A chat app that reuses similar answers, routes simpler questions to a smaller model, and shows modeled energy savings.

I handled the engineering and worked with one designer. The app combined a chat interface, semantic caching, model selection, and an energy dashboard.

Engineering by DongYeop Lee, working with one designer.View source

The numbers,
with their context.

Open the evidence ledger
modeled

Cache-hit energy: 98.6% modeled reduction

0.007 kWh/queryto0.0001 kWh/query
Source & method

You can
call me DY.

I'm DongYeop Lee, or DY. I spent Summer 2026 at Hemut working on voice agents and the backend behind them. That meant moving between conversations, code, and the tests that were supposed to tell me whether any of it worked.

Seeing issues in Converse sent me back to my own benchmark. I had already reached a conclusion, but the scorer needed another look. I care about that part of building just as much as getting the first version running.

This site is a project, too. I'm building mine first so my designer partner and I can learn from it before we build hers. Veracity and EcoPrompt are here for the same reason: I wanted to make the idea real and see what happened.

“I called my own agent. I got tired of waiting.”Why I went after the latency.

Voice agents
Backend infrastructure
AI evaluations

NLP at IDX Exchange
A browser extension
A hackathon with a designer

The one-page version