On the client, you are more likely to have a single API request. But on the server, you could be doing any mix of async things in a chain of dependencies + cond

On the client, you are more likely to have a single API request. But on the server, you could be doing any mix of async things in a chain of dependencies + conditional logic. Callback hell isn't a symptom of bad design. It's what happens when you have a lot of async function calls. Flattening callback hell often just contributes to callback hell with indirection, making it even harder to follow. But thankfully we have promises, now.