01 · Deployed data infrastructure
b2d_geo
39.7Mparcels
222Mland-use records
15 + 7REST routes · MCP tools
Go · PostGISproduction stack
Heejin Jo
Reliable AI startswhere benchmarks end.
I build and evaluate AI systems under real production constraints.
Selected work
Systems I built and operated.
Production infrastructureReal-time AIModel evaluation
02 · Live product · interview preparation
InterviewMate
Real-time inference path
Practice audio→
Streaming STT→
Prepared-answer match→
User-scoped retrieval→
Streamed suggestion
WebSocketFFmpegDeepgramQdrantClaude API
Production anomaly→Controlled studies→Activation probing
03 · Shipped product
TaskFlow AI
Documents→
Task decomposition→
Study workflow→
Notifications
How I build
Own the system. Test the behavior.
01
System ownership
ArchitectureDeploymentIncident response
→02
Model behavior
Controlled trialsGrader validationRegression checks
→03
Traceable evidence
Source metadataDeterministic checksClear boundaries
Research · 2026
Failure became evidence.
Production failure→
Prompt isolation→
210 rollouts→
Activation evidence
01arXiv:2607.16451 ↗
210 rollouts · 5 prompt conditions
Committed Before Reasoning
Behavioral reproduction and preliminary activation-level evidence of answer pre-commitment in an open-weight LLM.02arXiv:2602.21814 ↗
120 trials · 6 conditions
Prompt Architecture Determines Reasoning Quality
A variable isolation study on the Car Wash Problem.03arXiv:2603.13351 ↗
Production-prompt ablations
Prompt Complexity Dilutes Structured Reasoning
A follow-up study on the Car Wash Problem.System range
From data layer to model behavior.
01
Production systems
ArchitectureStreamingFallbacksAccess controlObservabilityCI/CD
02
Model behavior
EvaluationHuman reviewModel gradersRegression testsActivation probing
03
Backend & data
PythonGoTypeScriptFastAPIPostgreSQL / PostGISETL
04
Retrieval & agents
RAGQdrantChromaNeo4jLangGraphLangSmithMCP
Experience
Art → medicine → AI systems.
2026–Present
InterviewMate
Founder & AI EngineerReal-time AIEvaluationResearch
Oct 2022–Present
Birth2Death LLC
Founder & AI EngineerFounderAI productsData infrastructure
Apr–Oct 2023
Lime Friends
Python Developer / AI EngineerOn-premise NLPHealthcarePrivacy
Dec 2021–Apr 2023
SKIA
XR Specialist · Medical ImagingMedical imagingComputer visionXR
Education
Seoul Institute of the ArtsDigital Art · Sound DesignSt. George's UniversityAdmitted · MD programSelected awards
NASA International Space Apps ChallengeLocal Impact Award · 2025
AI Skin Burn Diagnosis Challenge1st Place · 2022
ICT AI Service Planning Program2nd Place · 2022
Metaverse Programmer Contest3rd Place · 2021
Contact