UCP Playground

UCP Playground

Walk through a complete UCP checkout flow step-by-step. This interactive demo runs entirely in the browser, simulating payloads and validating against real UCP schemas at each stage.

1. Platform Profile

Select the capability profile for the Platform. This determines which extensions (e.g., fulfillment, discounts) are negotiated.

Configuration

Supports basic checkout and order retrieval.

Capabilities 

      

    

    

      
    

  


  
  

    
2. Discovery

    
The Platform fetches /.well-known/ucp. The response below is filtered to show the intersection of the Business's capabilities and the Platform's profile.

    

      

        
GET Request

        
GET /.well-known/ucp HTTP/1.1
Host: business.example.com
Accept: application/json

      

      

        
Response (Filtered)

        

      

    

    

      
      
    

  


  
  

    
3. Capability Negotiation

    
Intersection of Platform and Business capabilities. Orphaned extensions are pruned.

    

      

        
Business Capabilities

        

      

      

        
Resulting Intersection

        

      

    

    

      
      
    

  


  
  

    
4. Create Checkout

    
The Platform initiates a session. The error response below follows the strict message.json schema.

    

      

        
Request Payload

        

      

      

        
Response

        

      

    

    
    

      Simulation Scenario:
      
      
    

    

      
      
    

  


  
  

    
5. Update Checkout

    
Patch the checkout with missing information to resolve validation errors.

    

      

        

          PATCH Request
          
        

        

      

      

        
Response

        

      

    

    

      
      
    

  


  
  

    
6. Mint Instrument

    
Simulate the payment handler flow to acquire a payment credential.

    

      

        
Select Handler

        

          Shop Pay

          com.shopify.shop_pay
        

        

          Google Pay

          com.google.pay
        

        
      

      

        
Minted Instrument

        

      

    

    

      
      
    

  


  
  

    
7. Complete Checkout

    
Submit the minted instrument to finalize the transaction and create an order.

    

      

        

          Request
          
        

        

      

      

        
Response (Order Created)

        

      

    

    
    

      
      
    

  


  
  

    
8. Webhook Simulation

    
Simulate a backend event (e.g., shipping center update) triggering a webhook push to the Agent.

    

      

        
Trigger Event

        
This action runs on the Business server and pushes data to the Platform's webhook URL.

        
      

      

        

          Webhook Payload (POST)
          Push Notification
        

        
// Waiting for event trigger...

      

    

    

      
    

  


  
  

    
About this demo

    
This playground is a simulation running entirely in your browser. It uses mocked logic to demonstrate the UCP protocol flow and isn't intended as a reference for production code. For real-world implementation examples and best practices, please check out our samples on GitHub.