Working with Outputs Flow enables you to test the triggers and actions at every step while configuring the workflow. This lets you see/use the outputs of those triggers and actions while configuring the rest of the workflow, and eliminate run-time errors. 

Let’s first understand about the webhook trigger output.

Webhook Trigger Output

A webhook is a user-defined HTTP callback. Flow supports incoming webhooks which allows external sources to notify Flow about a specific event. The output of a webhook trigger consists of three main keys:

1. headers - Contains header data sent to the webhook in key-value format

2. query - Contains query data sent to the webhook

3. body - Contains the data sent in the webhook body

These keys can then be used to configure the subsequent actions of the workflow, as shown below:


If you want to see the exact keys returned by each of the main keys, you can use the ‘Webhook Payload’ option given in the webhook configuration window.


The structure of the payload you add here should be similar to the one that the webhook is expected to receive in future. Flow uses this data to display the output of the webhook in the subsequent actions of your workflow.


Once you have entered the webhook payload data, click on ‘Next’. You will be displayed the data provided by you. Click on ‘Done’. 

Now when you connect any action to your webhook trigger, you can see the key-value pairs included in each key listed under the webhook output.

Web Service Trigger/Action Output

When you test a web service trigger/action, Flow uses an existing record of your web service account to test the configured settings and shows you the output of the trigger/action in the subsequent actions.

For example, you have configured ‘Trello - New List’ trigger and connected it to ‘Google Sheets - Add Rows’ action. So when you open the configuration window of ‘Google Sheets - Add Rows’ action, the output keys for ‘Trello - New Note’ trigger will look something like this:


Here, you will notice that each of keys included in the trigger output contains a sample value (fetched by the ‘test’ operation while configuring trigger).

If any item of the output keys is an array, click on the key name to see the key-value pairs associated with each array element. You can traverse through the array elements using the drop down field given beside the key name.