This comprehensive guide will walk you through setting up a flash sale on Shopify using Crowdhandler's virtual waiting room system to manage traffic, prevent overselling, and protect against bots and scalpers.
1: Install the Crowdhandler Shopify App
Install the Crowdhandler app directly from the Shopify App Store.
What this accomplishes:
- Provides seamless integration with your Shopify admin panel
- Automatically handles technical integration components
- Sets optimal defaults for flash sale scenarios
Learn more: Crowdhandler Shopify App Overview
2: Complete Initial Configuration
Once installed, navigate to the Crowdhandler app in your Shopify admin panel and complete these essential setup steps:
A. Add JavaScript Integration
The app automatically adds CrowdHandler JavaScript to your theme.liquid file for user validation, which ensures visitors are properly checked before accessing protected product detail pages (PDPs).
B. Enable Anti-Cheat Protection
Configure anti-cheat settings to protect against bots and scalpers:
- Prevent adding to cart when bypassing queue: This detects and prevents most bots and scalpers using automated software from proceeding to checkout
- Cancel orders that bypass queue: Inspects created orders for validity and triggers automated order cancellation for sophisticated bots that break through first-line defenses
- Automatically refund bypassed orders: Performs automatic refunds for cancelled bypass orders
The ability to cancel and refund orders is recommended if your product has been targeted by bots and scammers in the past.
Important note: Anti-cheat features are incompatible with branded accelerated checkout buttons displayed on product pages. Our JavaScript will automatically hide standard accelerated checkout options, but if you are offering non-standard payment options you may need to dissable these during yoru flash sale.
Learn more: Configure Anti-Cheat & Stock Syncing
3: Upgrade to Appropriate Plan
Choose from three tiers (Lite, Plus, Enterprise) based on your expected traffic and anti-cheat requirements:
- Lite Plan: Testing and very small sales (100 customers, 10/minute throughput)
- Plus Plan: Flash sales with moderate to high traffic, and requirring less onerous bot protection
- Enterprise Plan: High-volume stores requiring maximum capacity and advanced security
For products likely to be targeted by bots and scammers, we recommend the Enterprise plan for advanced anti-cheat settings. We also recommend enabling CrowdHandler's captcha protection to prevent queue abuse.
Learn more: Crowdhandler Shopify App Pricing
4: Set Up Product Protection Using the Mapper
Navigate to the product mapper in the Shopify app to configure waiting room protection:
For Single Products:
Click "Setup waiting room" for the specific product you'd like to protect. Your product will change to "protected" status.
For Collections:
Click "Setup waiting room" for the collection you want to protect. Your collection will change to "connected" and products within the collection will change to "protected".
Key decision: Determine whether you're protecting individual products, product variants, or entire collections based on your flash sale strategy.
Learn more: Mapping Your Products
5: Configure Waiting Room Timing in the Control Panel
Access the Crowdhandler control panel to set up timing:
A. Set Queue Activation Time
Set the date and time when users start being allowed through the queue. After this time, users will see their queue position and positions will tick down based on your set rate.
B. Configure Countdown Period
Set a countdown period from 15 minutes to 24 hours before your Queue Activates. This determines when your waiting room activates. Users will be kept off your product pages during the countdown, but will not be issued with a position until the queue activates.
Why use a countdown:
- Creates fairness for users
- Keeps customers off PDPs while you publish products
- Allows time for announcement emails
6: Configure Rate and One In One Out Settings
A. If Using Stock Availability Syncing (Recommended):
Enable stock syncing to make CrowdHandler Shopify inventory aware and automatically control one-in-one-out based on stock availability to prevent overselling. This also displays remaining inventory in the waiting room and shows sold-out messages when appropriate.
B. If Not Using Stock Syncing:
- Switch off one-in-one-out
- Control access rate manually using the dashboard rate setting
- Rule of thumb: Divide available stock by ten - if you have 1000 products to sell, a rate of 100 users per minute is recommended
Remember: The rate represents users admitted per minute, not a total number.
7: Customize Your Waiting Room Template
Access template customization in the Crowdhandler control panel:
Basic Branding (All Plans):
Upload your logo using the upload logo panel. The logo will be inserted at actual size, so resize to approximately 300 pixels for optimal display.
Template Customization (Paid Plans):
- Create custom HTML templates
- Use external URLs for dynamic content management
- Customize messaging for your specific product and audience
Minimum requirement: Upload your logo to ensure the waiting room matches your brand.
Learn more: Adding Templates
8: Publish Products and Send Announcements During Countdown
During the countdown period (before queue activation):
- Publish your products: Update inventory levels and make products live on your Shopify store
- Send announcement emails: Notify your customer base about the upcoming flash sale while the countdown is running
This approach ensures products are ready when the queue goes live while maintaining fair access for all customers.
9: Execute Your Flash Sale
Monitor Your Dashboard:
Use the CrowdHandler dashboard to view real-time activity, including active users on your website and users waiting in queues. During the countdown, you'll see queue size building up.
When Queue Activates:
Watch the activation line increase as users are admitted to your site at the configured rate.
Real-Time Adjustments:
Monitor your sales and adjust the rate if needed using the dashboard slider.
Learn more: The Dashboard
10: Post-Sale Cleanup and Closure
If Struggling to Sell Remaining Items:
Perhaps you are down to unpopular colours or sizes now and they're just not selling
- Increase the rate setting
- Switch off one-in-one-out to allow more users in
You can keep increasing the rate until the queue is empty or you are sold out.
When Sold Out:
- With stock syncing: Waiting room automatically displays sold-out message
- Without stock syncing: Post a message in the waiting room via the control panel
- Increase rate until queue empties
- Users will be redirected to product pages showing sold-out status
Safely Remove Protection:
- Use the control panel to disable or delete the waiting room
- Critical:Use the mapper to remove CrowdHandler tags from product pages
- Important: If you still have stock available, but anti-cheat features remain active without proper removal, users won't be able to add products to cart without going through the waiting room
Success Tips:
- Test your entire setup at least one week before your flash sale. You can test using low-interest products.
- Test your setup using incognito/private browsing sessions
- Start with conservative rate settings and adjust based on real-time performance
- Communicate clearly with customers about the waiting room process
By following this comprehensive guide, you'll be able to execute a successful flash sale that manages traffic effectively, prevents overselling, and provides a fair experience for all customers while protecting against automated abuse.
