Api And Debugging

Introducing Middleware: Enhanced API Efficiency and Flexibility with Reusable Logic


Hello, everyone! It's Chris from Xano. I'm thrilled to introduce our new feature: Middleware. Middleware represents a significant evolution in how you can manage and apply logic within your Xano function stacks. Let’s dive deep into what Middleware is and how you can leverage it to streamline your application’s functionality.

What Is Middleware?

Middleware is a reusable piece of logic that can be executed before or after specific points in your function stack. We have two types: Pre-middleware, which runs before input validation, and Post-middleware, which runs just before delivering a response. The beauty of Middleware lies in its ability to interact with data more dynamically compared to custom functions and its application scope – it can be applied to individual APIs, entire API groups, or across your entire workspace.

Why Middleware Over Custom Functions?

While custom functions are integral to Xano’s flexibility, Middleware brings two distinct advantages:

  • Data Interaction: Middleware can modify or replace data passed to it, offering unparalleled control.
  • Bulk Application: Apply Middleware across many APIs at once, dramatically reducing the time needed to implement widespread changes.

Middleware is particularly useful for scenarios like advanced input validation, customized API responses, or intricate data logging.

Getting Started with Middleware

Creating and applying Middleware is straightforward:

  1. Access Middleware: Head to the 'Library' section in Xano and find the Middleware option.
  2. Create and Configure: Define your Middleware logic, similar to crafting a custom function, but remember, inputs are inherited from the parent API.
  3. Response Type Decision: Decide whether your Middleware will ‘Merge’ (combine its output with the parent data) or ‘Replace’ (override the parent data entirely).

Applying Middleware

You can apply Middleware to an entire workspace, specific API groups, or individual APIs. This flexibility means you can quickly implement security checks, data transformations, or response formatting across numerous endpoints with minimal effort.

Real-World Example: Implementing a User Ban System

Let’s consider a practical scenario: rapidly deploying a user ban system across all your APIs. With Middleware, you can:

  1. Update your user database to include a 'banned' boolean.
  2. Create a Pre-middleware that checks this 'banned' status against the authenticated user.
  3. Apply this Middleware across all relevant APIs.

This approach drastically simplifies what would otherwise be a tedious process, allowing you to respond swiftly to real-world requirements.


Middleware in Xano opens up a world of efficiency and flexibility, providing you with powerful tools to enhance your applications. Whether you’re implementing complex validations, crafting personalized responses, or ensuring security protocols, Middleware can significantly streamline your workflow.

This transcript was AI generated to allow users to quickly answer technical questions about Xano.
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