Introduction to Flows Query Language

You can use Flows Query Language (FQL) to parse and transform JSON data to get the fields and structure you want.

FQL compared to TypeScript

The logic blocks in Postman Flows (If, Condition, and Evaluate) support both FQL and TypeScript. While FQL is designed for querying and transforming data, TypeScript offers the robustness and flexibility of a full programming language within your Postman Flows. This makes TypeScript more suitable for complex logic and large-scale projects. Also, if you are familiar with both the JavaScript and TypeScript ecosystems, you may prefer using TypeScript over FQL.

Extract fields from data with FQL

You can use FQL to extract specific fields from data passed between blocks. In this example, the Template block holds a customer_info JSON object. The variable data_field receives the formatted data and passes it into the Evaluate block where it can be queried with FQL. FQL in the Evaluate block prints out the values of customer_info. This example also includes a comment that uses the FQL /*comment*/ syntax.

Things you can do with FQL

The following pages show examples of things you can do with FQL:

• Get basic values
• Conditional data selection
• Return structured data
• Data manipulation

Using Postman Agent Mode with FQL

Not sure how to write an FQL statement for your flow? Use Postman Agent Mode! Tell Agent Mode what you want to do using plain language, and it will generate a FQL statement for you.

In the Evaluate block, drag the Agent Mode icon to the block’s text box or anywhere on the canvas to open Agent Mode. Enter your query as plain text in the Agent Mode text box and press the Return or Enter key. Agent Mode will suggest a query for you based on your prompt.

To learn more about how you can use Postman’s AI to help you use Flows, visit Postman Agent Mode.

FQL reference

For a complete reference for all FQL functions, see the FQL function reference.