API FIELD LAB / 01

Follow the request.

One message. Every boundary.
AI writes code. You understand it.

Ready. Send a message, then slow down the story.

No transaction yet

01 The journey

READY

Teaching replay. Network requests run at normal speed.

Request and response journeyJavaScript hands the request to browser networking. The API responds. The browser reads the JSON and JavaScript updates the page. The Promise stays with JavaScript. SENDRETURN JavaScriptyour async function Browsernetworking httpbin APIexternal server Parsed objectJavaScript data Your pagerendered result
Promise lives here
Waiting for your first messageServer internals are a simplified illustration.

02 The actual code

app.js

Source from the running request function. The active lines light up.


    

    

      
03 Request / response
—

      
App-recorded evidence. Verify the HTTP transaction in DevTools Network.

      
GETThe request URL appears at step 2.
TIMEActual duration appears when the replay reaches the response.

      
The parsed response appears at step 6.

    

    

      
04 App logs
console.log

      
Same events sent to the real Console. Replay reveals them one step at a time.

      
The first clue starts with a click.

    

  

  
  

    
A successful request can still produce a bug.
Inspect the object before trusting your assumptions.

    
    
  

  
Use F12 to open real DevTools. Arrow keys step through replay when focus is outside inputs. Send only non-sensitive messages. Three-minute presenter guide