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The AI-Powered Classifieds Stack That Posts in Seconds

Users can upload a photo to 24ad.info. AI assists with the listing details. The ad goes live before any manual steps are complete. Here's how the stack works.

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The Pipeline

1. Vision Processing (OpenRouter + Gemini 2.5 Flash)

When you upload photos:

Key observations:

• Processes images quickly
• Handles mixed content
• Price suggestions draw on available data

2. Category Assignment

The system first tries keyword matching. If uncertain, it queries the classification options.

Two clever bits:

Dormant category reactivation - Instead of creating duplicate categories, it finds and revives inactive ones #

Custom field generation - For categories like Cars, AI suggests relevant fields

3. Multilingual Output

Using the same call flow, translations are generated. The response lands in our locales/

directory with i18n keys.

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The Stack That Makes It Possible

Frontend

React 19 + Vite 7 - For the instant form updates #

shadcn/ui - Pre-built components with Tailwind #

wouter v3 - Lightweight routing (no React Router bloat) Critical UX details:

• File upload starts analysis during selection
• Price/category suggestions appear as editable previews
• Location auto-fills from browser geolocation or IP

Backend

tRPC v11 - Keeps frontend/backend types in sync #

Drizzle ORM - For type-safe MySQL queries #

Express 4 - Handles the traffic types:

• User requests (API/SSR)
• Googlebot HTML injection
• Health checks ( /api/system-health

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Infrastructure

Caddy v2 - Wildcard subdomains with HSTS #

PM2 cluster mode with 4 instances - load-balanced #

MariaDB - Heavily indexed for search (title, location, price)

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Pain Points We Solved

1. AI Latency

Initial versions waited for all AI steps sequentially. Now:

Parallel processing - Fire all AI requests simultaneously #

Fallback caching - Common items use template descriptions if needed

2. Location Handling

Early users saw unexpected placement. Fixed by:

Subdomain locking - Forces location based on subdomain #

Clear labels - Shows target country

3. Spam Protection

Current defenses include:

AI content check - Flags suspicious patterns #

IP/email blacklist - Shared across country subdomains #

Stripe verification - Premium ads require validated payment

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The Admin Toolkit

Moderators get bulk tools plus:

AI banner rotator - Generates event-specific graphics #

Health monitor - Checks subsystems including font rendering and upload permissions

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Performance

Median ad creation time is low. Category handling is accurate.

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Lessons Learned

AI isn't magic - Pricing suggestions benefit from additional rules.

Condition detection - The AI spots visible details in photos.

Speed matters - The entire process must fit within user attention.

Try it yourself: 24ad.info.

source & further reading

dev.to — original article Run Claude Code For Free (for Fun and Profit) First Post The #1 Developer Skill in the Agentic Era