HEYI.

HEYI (“Hey, AI!”) is a Chrome extension built in 24 hours at HackTCNJ 2026 to help shoppers judge whether ecommerce content may be AI-generated before they buy.

Timeline
HackTCNJ 2026 — 24-hour build
Role
Co-creator — extension UI, Gemini integration, backend and product flow
Stack
Chrome Extension API · Node · Express · MongoDB · Hugging Face · Gemini
HEYI logo

Overview

The project started from a practical trust problem: AI-generated listings and product visuals are increasingly hard to spot, especially for less technical shoppers. The goal was to provide fast, understandable risk signals directly in browsing context rather than in a separate tool.

HEYI won Best Use of Gemini API at HackTCNJ 2026. I built the extension UI and API integration flow, while Isabel DiFabio trained and hosted the text classifier on Hugging Face. The final product connected scanning, confidence scoring, and domain memory into one clear user flow.

Core User Flow

The extension works in two modes. If a domain has already been scanned and stored, users immediately get a proactive warning based on existing history. If not, they can trigger a fresh scan from the popup and receive a 0–100 confidence score indicating how likely the page content is AI-generated.

The score view is intentionally plain-language: a confidence number, short caution message, and a clear next action to scan again. The design choice was deliberate—under hackathon constraints, product clarity mattered more than adding extra technical controls.

HEYI extension popup before scanning a page HEYI scan result showing confidence score and caution guidance
Workflow view: extension entry state and score view shown after scanning, with confidence and plain-language guidance.

Architecture

Extension scripts collect page text and metadata, then call an Express backend for inference routing. The backend queries the Hugging Face-hosted text model and uses Gemini for complementary image signal. MongoDB stores domain-level history to support proactive warnings on future visits.

The hardest part was integration speed under a 24-hour deadline: extension, model endpoint, Gemini API, and persistence all had to stay reliable enough for a live judging demo.

Implementation Highlights

Two-stage warning model

Known domains trigger immediate caution; unknown domains run on-demand scanning with a confidence score.

UI clarity under uncertainty

Results are phrased as confidence guidance, not absolute verdicts, to avoid over-trusting model output.

Rapid API integration

Gemini, Hugging Face inference, and MongoDB were wired into one extension workflow fast enough for judging.

Results

HEYI won Best Use of Gemini API at HackTCNJ 2026 and was later published to the Chrome Web Store. Judges responded strongly to its practical utility and clear communication model.

Reflection

The project reinforced a key product lesson: ML ambition only matters if users understand the output quickly. Building HEYI improved how I integrate external APIs and how I communicate model confidence in a way that helps real-world decision making.

LinkedIn

LinkedIn post from the hackathon launch and presentation.

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