Step-by-Step Guide: Building an eBay Clone with Adalo

Why Adalo Works for Building an eBay-Style Marketplace

Adalo is a no-code app builder for database-driven web apps and native iOS and Android apps—one version across all three platforms, published to the Apple App Store and Google Play. This cross-platform capability is essential for marketplace apps like eBay, where buyers and sellers expect seamless access whether they're browsing on desktop, checking bids on their iPhone, or listing items from an Android tablet.

Native app store distribution gives your marketplace a critical advantage: push notifications. Alert users instantly when they're outbid, when an auction they're watching is ending, or when a seller responds to their message. This real-time engagement drives repeat visits and keeps your marketplace active. Combined with Adalo's visual database builder for managing listings, users, bids, and transactions, you have everything needed to launch a fully functional auction platform.

Building a marketplace app like eBay requires handling complex data relationships—listings, users, bids, transactions, and seller profiles—across multiple platforms. Traditional development means building and maintaining separate codebases for web, iOS, and Android, tripling your work and timeline.

Adalo, an AI-powered app builder, solves this by letting you build once and deploy everywhere. Create your marketplace with a visual drag-and-drop interface, and publish the same app to web, the Apple App Store, and Google Play Store from a single codebase. With unlimited database records on paid plans and infrastructure that scales to over 1 million monthly active users, your auction platform can grow without hitting artificial ceilings.

This comprehensive tutorial walks you through building a functional eBay-style marketplace with user authentication, bidding systems, payment processing, and seller management—all without writing code.

Why Adalo Works for Building an eBay-Style Marketplace

For a marketplace to succeed, it needs to reach buyers and sellers wherever they are—desktop, iPhone, or Android. Adalo's single-codebase approach means you build once and deploy everywhere, giving your auction platform maximum reach without duplicating effort.

Native app store distribution unlocks push notifications to alert users about outbid items, auction endings, and new messages from buyers. This keeps engagement high and drives more sales through your platform. The platform's modular infrastructure handles apps with millions of MAU, so you won't need to rebuild when your marketplace gains traction.

Ada, Adalo's AI builder, lets you describe what you want and generates your app. Magic Start creates complete app foundations from a description, while Magic Add adds features through natural language.

While some advanced features like real-time bidding require workarounds, you'll create a functional auction and buy-it-now marketplace that publishes to web, native iOS, and native Android—all from the same build.

Prerequisites and Initial Setup

Step 1: Create Your Adalo Account

  1. Go to Adalo.com and sign up
  2. Click "Create New App"
  3. Choose "Mobile App" for full functionality
  4. Name your app (e.g., "AuctionHub")
  5. Select "Start from Scratch" or use Magic Start to generate a foundation from a description

Step 2: Configure App Settings

  1. Choose primary color (blue conveys trust for financial transactions)
  2. Select a professional font family
  3. Set up navigation structure
  4. Click "Continue" to enter the editor

Step 3: Install Required Components

  1. Visit the Adalo Marketplace
  2. Install these components:
    • Star Rating (for seller reviews)
    • Progress Bar (for auction timers)
    • Calendar (for auction scheduling)
    • Maps (for location features)

Setting Up the Database

A marketplace requires several interconnected collections. With Adalo's no record limits on paid plans, you can store as many listings, bids, and transactions as your marketplace generates without worrying about hitting caps.

Step 4: Configure the Users Collection

  1. Click Database in the left sidebar
  2. Select the default "Users" collection
  3. Add these properties:
    • Profile Picture (Image)
    • Display Name (Text)
    • Phone Number (Text)
    • Is Seller (True/False - default: false)
    • Is Buyer (True/False - default: true)
    • Average Rating (Number - default: 0)
    • Total Sales (Number - default: 0)
    • Stripe Account ID (Text)
    • Address, City, State, Zip Code (Text)

Learn about the Users collection

Step 5: Create Categories Collection

  1. Click "+ Add Collection"
  2. Name it "Categories"
  3. Add properties:
    • Name (Text)
    • Description (Text)
    • Image (Image)
    • Is Active (True/False - default: true)
    • Sort Order (Number)

Step 6: Create Listings Collection

  1. Click "+ Add Collection"
  2. Name it "Listings"
  3. Add properties:
    • Title (Text)
    • Description (Text - Multiline)
    • Starting Price, Current Bid, Reserve Price, Buy Now Price (Number)
    • Primary Image, Image 2, Image 3 (Image)
    • Condition (Text) - Values: "New", "Used", "Refurbished"
    • Auction End Date (Date & Time)
    • Is Active, Is Auction, Has Reserve (True/False)
    • Listing Type (Text) - Values: "auction", "buy_now", "both"
    • Created Date (Date & Time - Automatic)
    • Views Count (Number - default: 0)

Step 7: Create Bids Collection

  1. Click "+ Add Collection"
  2. Name it "Bids"
  3. Add properties:
    • Bid Amount (Number)
    • Bid Date (Date & Time - Automatic)
    • Is Winning Bid (True/False - default: false)
    • Is Auto Bid (True/False - default: false)

Step 8: Create Transactions Collection

  1. Click "+ Add Collection"
  2. Name it "Transactions"
  3. Add properties:
    • Final Price (Number)
    • Transaction Date (Date & Time - Automatic)
    • Payment Status (Text) - Values: "pending", "completed", "failed"
    • Shipping Status (Text) - Values: "not_shipped", "shipped", "delivered"
    • Stripe Payment ID (Text)

Step 9: Create Reviews Collection

  1. Click "+ Add Collection"
  2. Name it "Reviews"
  3. Add properties:
    • Rating (Number)
    • Comment (Text - Multiline)
    • Review Date (Date & Time - Automatic)
    • Review Type (Text) - Values: "buyer", "seller"

Step 10: Set Up Database Relationships

  1. In Listings:
    • Add "Seller" → Users (Many to One)
    • Add "Category" → Categories (Many to One)
  2. In Bids:
    • Add "Bidder" → Users (Many to One)
    • Add "Listing" → Listings (Many to One)
  3. In Transactions:
    • Add "Buyer" → Users (Many to One)
    • Add "Seller" → Users (Many to One)
    • Add "Listing" → Listings (Many to One)
  4. In Reviews:
    • Add "Reviewer" → Users (Many to One)
    • Add "Reviewed User" → Users (Many to One)
    • Add "Transaction" → Transactions (Many to One)

Database relationships guide

Building Core Marketplace Screens

Step 11: Create Home Screen

  1. Add new screen "Home" and make it the home screen
  2. Add Text component for app title
  3. Add Search Bar component
  4. Add Custom List for featured categories:
    • Data: Categories
    • Filter: Is Active = true
    • Show: Name, Image
    • Click action → "Category Listings" screen

Step 12: Build Browse Categories Screen

  1. Add new screen "Category Listings"
  2. Add Custom List for listings:
    • Data: Listings
    • Filter: Category = Selected Category AND Is Active = true
    • Show: Title, Primary Image, Current Bid, Time Remaining
  3. Add Sort/Filter buttons
  4. Click action → "Listing Detail" screen

Step 13: Create Listing Detail Screen

  1. Add new screen "Listing Detail"
  2. Add Image component for primary image with swipe gallery
  3. Display listing information: Title, description, current bid/Buy Now price, time remaining, seller info and rating
  4. Add conditional buttons:
    • "Place Bid" (if auction)
    • "Buy It Now" (if available)
    • "Watch Item" toggle

Note: Increment the Views Count property when users open this screen to track listing popularity.

Step 14: Implement Bidding Interface

  1. Add new screen "Place Bid"
  2. Add Number Input for bid amount
  3. Add validation text showing minimum bid and user's maximum bid
  4. Add bid history Custom List:
    • Data: Bids filtered by current listing
    • Sort: Bid Date (Descending)
    • Show: Bid Amount, Bidder (anonymous), Time

Step 15: Create Seller Dashboard

  1. Add new screen "Seller Dashboard"
  2. Add tabs: Active Listings, Sold Items, Draft Listings
  3. Add Custom Lists for each tab
  4. Add "Create Listing" button → "Create Listing" screen

Implementing Payment Integration

Step 16: Set Up Stripe Connect

  1. Open the Marketplace in the editor
  2. Add the Marketplace Payments component to your Checkout screen
  3. Configure Stripe Connect: Test/Live mode, platform fee percentage, currency
  4. Add seller onboarding flow

Stripe Marketplace Payments documentation

Step 17: Create Seller Onboarding

  1. Add new screen "Become Seller"
  2. Add form fields for business information, bank account details, and tax information
  3. Connect to Stripe Express accounts
  4. Update Users → Is Seller = true on completion

Step 18: Build Checkout Process

  1. Add new screen "Checkout"
  2. Display order summary
  3. Add shipping information form
  4. Add Marketplace Payments component with platform fee and success/failure actions

Building Auction Timer System

Step 19: Create Timer Logic

  1. Add Text component for countdown display
  2. Use conditional logic:
    • If Current Time < Auction End Date → Show remaining time
    • If Current Time ≥ Auction End Date → Show "Auction Ended"
  3. Add Progress Bar showing time percentage remaining

Note: Adalo doesn't automatically refresh auction timers. Use push notifications for bid updates or integrate a custom backend for real-time-like behavior.

Step 20: Implement Bid Processing

  1. On "Place Bid" action:
    • Validate bid amount > current bid
    • Create new Bid record
    • Update Listing → Current Bid
    • Update all other bids → Is Winning Bid = false
    • Set new bid → Is Winning Bid = true
    • Send push notification to previous high bidder

Step 21: Handle Auction Endings

  1. Create screen "Auction Results"
  2. Display winning bid information and checkout option for winner
  3. Send notifications to winner and seller
  4. Update listing status to inactive

Adding User Features

Step 22: Build User Profiles

  1. Add new screen "User Profile"
  2. Display profile picture, name, average rating, total sales, and recent feedback
  3. Add "View Items" button
  4. Show seller verification badges

Step 23: Create Review System

  1. Add new screen "Leave Review"
  2. Add Star Rating component and Text Input for comments
  3. Link to completed transaction
  4. Update user's average rating automatically

Step 24: Implement Watchlist

  1. Create "Watchlist" collection with User relationship, Listing relationship, and Date Added
  2. Add "Watch" toggle on listing detail
  3. Create "My Watchlist" screen
  4. Send notifications for watched item updates

Working with Platform Considerations

Step 25: Handle Real-Time Updates

Considerations:

Workarounds: Use push notifications for bid alerts, add manual refresh buttons, or integrate Xano for real-time-like functionality.

Step 26: Optimize Performance

Adalo 3.0's infrastructure overhaul made apps 3-4x faster than previous versions. To maximize performance:

  1. Limit list items to 20-30 per screen
  2. Use pagination for long lists
  3. Compress images before upload (50MB limit)
  4. Add loading states and progress indicators
  5. Use conditional visibility strategically

X-Ray, Adalo's built-in performance tool, identifies issues before they affect users—helping you maintain speed as your marketplace grows.

Step 27: Implement Search Functionality

  1. Add Search Bar to main screens
  2. Use "contains" filter for text search
  3. Add category and price filters
  4. Create advanced search screen with multiple criteria

Testing and Launch Preparation

Step 28: Test Core Workflows

  1. Create test seller and buyer accounts
  2. Test complete listing creation process
  3. Verify bidding and buy-now functionality
  4. Test payment processing (use Stripe test mode)
  5. Confirm notification delivery
  6. Test on multiple devices and platforms

Step 29: Set Up Analytics

  1. Enable Adalo analytics in settings
  2. Add custom tracking for listing views, bid placements, and completed transactions
  3. Set up conversion funnels

Step 30: Prepare for Publishing

  1. Upgrade to a paid plan (starting at $36/month with unlimited usage and app store publishing)
  2. Configure app store settings
  3. Create privacy policy and terms of service
  4. Set up customer support system

Advanced Features and Enhancements

Step 31: Add Location Features

  1. Install Maps component from marketplace
  2. Add location field to listings
  3. Create "Local Items" filter
  4. Implement pickup options for transactions

Step 32: Create Admin Panel

  1. Add admin role to Users collection
  2. Create admin-only screens for user management, listing moderation, transaction monitoring, and dispute resolution
  3. Add reporting and analytics views

Step 33: Implement Messaging System

  1. Add Chat component for buyer-seller communication
  2. Link conversations to specific listings
  3. Add message notifications
  4. Create conversation history screens

Chat component guide

External Service Integrations

Step 34: Set Up Zapier Automation

  1. Create Zapier account
  2. Connect Adalo triggers: New listing created, Auction ended, Payment completed
  3. Automate email notifications and data sync

Step 35: Add Advanced Backend

For complex logic beyond Adalo's built-in capabilities, consider Xano integration for complex calculations, advanced search, and real-time features.

Important Considerations

Cost Breakdown:

Platform Considerations:

Recommended Architecture:

Additional Resources

This eBay-style marketplace provides core auction and buy-it-now functionality with user authentication, payment processing, and seller management. While real-time bidding requires workarounds, the platform's unlimited database storage and scalable infrastructure create a solid foundation for growth—and you can publish to web, iOS, and Android from a single build.

FAQ

Why choose Adalo over other app building solutions?

Adalo is an AI-powered app builder that creates true native iOS and Android apps from a single codebase. Unlike web wrappers, it compiles to native code and publishes directly to both the Apple App Store and Google Play Store. With unlimited database records on paid plans and infrastructure that scales to 1M+ MAU, your marketplace can grow without hitting artificial limits.

What's the fastest way to build and publish an app to the App Store?

Adalo's drag-and-drop interface and AI-assisted building let you go from idea to published app in days rather than months. Magic Start generates complete app foundations from descriptions, and Adalo handles the complex App Store submission process—so you can focus on features instead of certificates and provisioning profiles.

Can I build an eBay-style marketplace app without coding?

Yes. With Adalo's visual builder, you can create user authentication, listing management, bidding systems, payment processing with Stripe, and seller dashboards through drag-and-drop—no code required. The same app publishes to web, iOS, and Android.

Does Adalo support real-time bidding for auction apps?

Adalo doesn't support automatic real-time screen refreshes. However, you can work around this with push notifications to alert users about bid updates, manual refresh options, or integrating a backend service like Xano for real-time-like behavior.

How do I handle payments and seller payouts in an Adalo marketplace?

Adalo integrates with Stripe Connect through the Marketplace Payments component. You can process payments and automatically split funds between buyers, sellers, and your platform. Set your own platform fee percentage and onboard sellers with Stripe Express accounts.

How much does it cost to build a marketplace app with Adalo?

Adalo plans start at $36/month with unlimited usage and app store publishing. Unlike competitors with usage-based charges and record limits, Adalo's paid plans include unlimited database records and no bill shock from unexpected usage fees.

Which is more affordable, Adalo or Bubble?

Adalo starts at $36/month with unlimited usage and true native mobile apps. Bubble's comparable offering starts at $59/month with usage-based Workload Unit charges and record limits. Bubble's mobile solution is also a web wrapper rather than native compilation.

Which is better for mobile marketplace apps, Adalo or Glide?

Adalo is better for marketplace apps requiring App Store publishing. Glide starts at $60/month but doesn't support Apple App Store or Google Play Store publishing, and charges for additional data rows. Adalo publishes native apps to both stores from a single codebase.

What database collections do I need for a marketplace app?

A functional marketplace requires Users (buyers and sellers), Categories, Listings, Bids, Transactions, and Reviews collections. You'll set up relationships linking listings to sellers, bids to bidders and listings, and reviews to transactions.

Can I add messaging between buyers and sellers?

Yes. Adalo's Chat component enables buyer-seller communication linked to specific listings. You can send message notifications via push notifications and create conversation history screens for users to review their communications.