From Raw Notes to First Sale: The Complete Guide to Building a Privacy-First E-Commerce AI Copywriter with Google Gemma 2 & ElevenLabs

Hacktoberfest Open-Source AI Challenge Week 2: Side Hustle Submission 💸

Submitted for the **Hacktoberfest Open-Source AI Challenge: Week 2 — Side Hustle.

If you run an e-commerce side hustle—selling vintage decor, handcrafted leather goods, custom mechanical keyboards, or 3D-printed workshop tools—you know the feeling: creating the item is the fun part. Writing listings for multiple marketplaces is painful.

Each marketplace speaks its own dialect:

┌─────────────────┐ ┌────────────────────────────────────────────────────────┐ │ Raw Item Notes │ ──► │ How do I write 3 different formats for Etsy, Amazon, │ │ "Leather card │ │ & eBay without paying $30/mo or giving up my catalog? │ │ holder wallet"│ └────────────────────────────────────────────────────────┘ └─────────────────┘ Enter fullscreen mode Exit fullscreen mode Why Existing Cloud Solutions Fail Side-Hustlers The Subscription Tax: $20–$50/month per-seat fees or unpredictable OpenAI API token bills eat away at thin profit margins on $15–$30 items. Catalog Privacy & Leakage: Side-hustlers often draft listings weeks before a collection drop. Unreleased designs, wholesale margins, and proprietary supplier details get fed into commercial cloud LLMs.

The "Silent Copy" Trap: When writing copy silently in your head, awkward phrasing slips through. You only discover your listing sounds stiff and robotic after a buyer ignores it. ListingGenius was built to solve all three issues:

Watch ListingGenius in action generating listings with Google Gemma 2 and auditioning voice with ElevenLabs:

Here is the live generator in action showing the new marketplace card selector and generated listing output:

Instead of struggling over sentence structure, sellers select their target marketplace ( Etsy, eBay, or Amazon ) and paste raw bullet points or photos:

Product: Minimalist front pocket cardholder wallet Material: Full grain Italian vegetable-tanned leather Capacity: Holds 8 cards + cash slot Features: Hand-stitched with waxed linen thread, RFID blocking layer Who it's for: Everyday carry enthusiasts, minimalist gift idea Enter fullscreen mode Exit fullscreen mode Step 2: Local Gemma 2 Inference ($0 Cost & Instant JSON) When the user clicks "✨ Generate Listing", the request hits the local Ollama instance running Google's gemma2:latest.

Gemma 2 evaluates the marketplace prompt template and returns structured JSON containing:

Once generated, the seller clicks "Read Aloud".

ListingGenius calls ElevenLabs' eleven_multilingual_v2 model with natural speech synthesis:

┌──────────────────────────────────────────────────────────────────┐ │ Next.js 16 (App Router & Turbopack) │ │ • Marketplace Switcher (Etsy / Amazon / eBay) │ │ • Form Input & One-Click Copy System │ │ • Audio Waveform & MP3 Streamer │ └─────────────────────────────────┬────────────────────────────────┘ │ ┌───────────────┴───────────────┐ ▼ ▼ ┌──────────────────────────────┐┌──────────────────────────────┐ │ Google Gemma 2 ││ ElevenLabs TTS Engine │ │ (Local Ollama Inference) ││ (eleven_multilingual_v2) │ │ ││ │ │ • Runs on localhost:11434 ││ • Lifelike voice synthesis │ │ • Zero API Token Bills ││ • Audio auditioning │ │ • 100% Private & Offline ││ • TikTok/Reels exportable │ │ • Structured JSON Schema ││ • Natural phrasing validator │ └──────────────────────────────┘└──────────────────────────────┘ Enter fullscreen mode Exit fullscreen mode The Prompt Architecture To ensure Gemma 2 produces predictable, production-ready listings, we constructed platform-tailored system instructions that constrain output to verified JSON schemas:

// lib/prompts.ts export function getPlatformPrompt ( platform: Platform, notes: string ) { const constraints = { etsy: " Craft an emotional, artisanal narrative. Emphasize craftsmanship and materials. Provide 13 search tags.

", amazon: " Create 5 structured bullet points highlighting benefits, dimensions, and materials. Include high-intent SEO keywords. ", ebay: " Prioritize clear condition grading, precise technical specs, and reassuring buyer policies (shipping/returns).

" }; return { system: `You are an elite e-commerce copywriter. Output MUST be valid JSON with keys: title, description, tags, callToAction.`, user: `Target Platform: ${ platform }. Specifications: ${ constraints [ platform ]}.

Product Notes: ${ notes } ` }; } Enter fullscreen mode Exit fullscreen mode ⚡ Quickstart: Run It Locally in 3 Steps Want to run ListingGenius on your laptop for your own products?

# Install Ollama curl -fsSL https://ollama.com/install.sh | sh # Pull Google's open-weight model (5.4 GB) ollama pull gemma2 Enter fullscreen mode Exit fullscreen mode 2. Clone the Repository & Install Dependencies git clone https://github.com/Imbiber/listing-genius.git cd listing-genius npm install Enter fullscreen mode Exit fullscreen mode 3. Add Keys & Start Create.env.local:

ELEVENLABS_API_KEY=your_key_here OLLAMA_BASE_URL=http://localhost:11434 Enter fullscreen mode Exit fullscreen mode Start development server:

npm run dev Enter fullscreen mode Exit fullscreen mode Open http://localhost:3000 and start generating!

ListingGenius was planned, built, and debugged collaboratively using an AI coding agent. We configured local Ollama fallback pipelines, fixed deprecated ElevenLabs model endpoints, and styled the UI.

You can inspect the entire prompt history, tool calls, and code diffs in the interactive transcript on DEV:

Are you a maker, vintage curator, or digital seller? What marketplace formats would you like added next (Shopify, Depop, Poshmark)? Let me know in the comments below!