# INVALID_ROUTING_MODEL – Backward Route Not Allowed in Routing Model in WhatsApp Flows
Author: Prashant Jangid
Author URL: https://www.heltar.com/blogs/author/prashant-jangid
Published: 2025-04-16
Category: Troubleshoot
Category URL: https://www.heltar.com/blogs/category/troubleshoot
Tags: WhatsApp Flows Error
Tag URLs: WhatsApp Flows Error (https://www.heltar.com/blogs/tag/whatsapp-flows-error)
URL: https://www.heltar.com/blogs/invalidroutingmodel-backward-route-not-allowed-in-routing-model-in-whatsapp-flows-cm9jtjja3008814n53fpz1lak

If you're working with WhatsApp data channel flow JSON and see this error:

**INVALID\_ROUTING\_MODEL: Backward route \[(destination)-)(source)\] corresponding to forward route \[(source)-)(destination)\] is not allowed in the routing model. Only forward routes can be specified.**

You're likely defining bidirectional routing, which the system doesn't support. Here’s why it happens and how to fix it.

### What This Error Means

The routing model in WhatsApp flows must only move forward. You cannot define a path from Screen A to Screen B and then also from B back to A. That creates a backward route, which is not allowed.

### Example That Triggers the Error

```
{
  "routing_model": {
    "FIRST_SCREEN": ["SECOND_SCREEN"],
    "SECOND_SCREEN": ["FIRST_SCREEN"]
  }
}
```

This setup tells the system:

- FIRST\_SCREEN leads to SECOND\_SCREEN

- But SECOND\_SCREEN also leads back to FIRST\_SCREEN


This two-way routing creates a loop that prevents a clear forward flow, resulting in the INVALID\_ROUTING\_MODEL error.

### How to Fix It

To resolve the error:

- Remove any reverse or backward links in your routing\_model

- Ensure that your flow only moves one-way from screen to screen


#### Fixed Example

```
{
  "routing_model": {
    "FIRST_SCREEN": ["SECOND_SCREEN"]
  }
}
```

In this version:

- The flow moves from FIRST\_SCREEN to SECOND\_SCREEN

- There is no route going back

- This structure is valid and won’t trigger an error


If your experience requires users to “go back,” it should be implemented using a different mechanism—like restarting the flow, using a separate path, or offering a new interaction from a terminal screen.

For more troubleshooting insights related to WhatsApp Business API, check out [heltar.com/blogs](http://heltar.com/blogs).


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