Power Automate  

How to Create and Use Subflows in Power Automate Desktop Like a Pro (PAD)

Hello developers!

In this post, I’ll walk you through how to use Subflows in Power Automate Desktop to make your automation cleaner, more modular, and easier to maintain. Whether you’re automating Excel tasks, working with files, or building a complex RPA flow, subflows are going to be your best friends.

As a fellow developer working in Power Platform for the last couple of years, I’ve realized one thing: if you don’t structure your flows properly, they can become a nightmare real quick. That’s where subflows come in.

What is a Subflow?

Think of a subflow as a function or method in C#. It’s a reusable block of logic that you can call from your main flow (or even from another subflow).

Instead of repeating the same set of actions multiple times, you can simply extract that logic into a subflow and reuse it. That means,

  • Better readability
  • Fewer chances of bugs
  • Easy to maintain
  • Looks clean and pro

Step-by-Step: How to Create a Subflow in Power Automate Desktop

Let’s take a simple example. Suppose you’re writing a flow to read data from a CSV file and process each row.

You can break down your logic like this.

  • Step 1: Read the CSV
  • Step 2: Loop through each row
  • Step 3: For each row, perform some action (say, update SharePoint or Excel)

Step 1. Create the Subflow.

  1. Open Power Automate Desktop.
  2. Click on the “Subflows” tab (top section of your screen).

Subflows

Click “+ New subflow” and give it a name, e.g., ProcessRowSubflow.

New subflow

Inside the subflow, add your logic, maybe a condition, some data manipulation, API call, etc.

For testing, I am adding a message box.

For testing

Pro Tip: Always use meaningful names for your subflows. Avoid naming them like “Subflow1”, “TestFlow”, etc. Future-you will thank you!

Step 2. Call the Subflow.

  1. Go back to your main flow.
  2. Use the “Run Subflow” action from the Actions pane.
    Run Subflow
  3. Select the subflow you just created.
    Save

Done! Your subflow will now run like a method call.

Done

Output

Output

Passing Parameters to Subflows

Yes, you can pass values to your subflow just like you pass arguments to a function in code.

How?

  1. Go to the subflow and click on the Input/Output tab.
  2. Add the input variables you want, like RowData, UserName, etc.

Output tab

In the “Run Subflow” action, map values from your main flow to these input fields.

Main flow

Main flow

You can also return output by defining output parameters in the same tab.

Tab

Why You Should Use Subflows?

Let’s be honest, some flows grow big and ugly very fast. When your flow is 200 lines long and you’re scrolling endlessly to debug a small issue, trust me, it’s frustrating.

Subflows help you avoid this. They act like mini-components that isolate your logic. Here’s why I prefer them,

  • Improves code quality
  • Makes debugging easier
  • Great for team collaboration
  • Encourages reusability
  • Feels like coding in C# again

Best Practices (From My Experience)

  • Keep subflows short and specific. One subflow = one job.
  • Add comments inside your subflow, just like you’d comment your code.
  • Handle exceptions properly. Use the “On Error” block where needed.
  • Don’t overuse subflows — keep a balance.

Final Thoughts

If you’ve not been using subflows in Power Automate Desktop yet, this is your sign to start now!

It makes your flows much more developer-friendly and aligns beautifully with how we write structured, clean code in traditional programming.

Hope this article helps you out in your RPA journey. If you liked it or learned something new, do drop a comment or connect with me on C# Corner. Let’s grow together!

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