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.

The Pipeline

1. Vision Processing (OpenRouter + Gemini 2.5 Flash)

When you upload photos:

// Simplified image analysis flow

const analysis = await openRouter.chat.completions.create({

  model: "google/gemini-2.5-flash",

  messages: [{

    role: "user",

    content: [

      { type: "image_url", url: uploadedImage },

      "Describe this item for a classified ad. Identify make/model, condition, and realistic price."

    ]

  }]

});

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:

1. 
   Dormant category reactivation - Instead of creating duplicate categories, it finds and revives inactive ones
   


2. 
   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.

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:
  
  
  
  
  1. User requests (API/SSR)
     
  
  
  2. Googlebot HTML injection
     
  
  
  3. Health checks (/api/system-health)
     
  
  
  
  

Infrastructure

• 
  Caddy v2 - Wildcard subdomains with HSTS
  


• 
  PM2 cluster mode with 4 instances - load-balanced
  


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

CREATE TABLE `posts` (

  `id` bigint AUTO_INCREMENT PRIMARY KEY,

  `title` varchar(191),

  `price` decimal(17,2),

  `country_code` varchar(2),

  `latitude` float,

  `longitude` float

  -- geolocation uses standard B-tree index on latitude/longitude

);

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
  

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
  

Performance

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

Lessons Learned

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




2. Condition detection - The AI spots visible details in photos.




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

Try it yourself: 24ad.info.