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You can use custom data files (CSV or JSON) when running a collection manually in Requestly.
This enables you to iterate through your requests using multiple sets of input values, without modifying your request parameters each time.
Note: This feature is currently available only on the Requestly Desktop App.
Use this feature to test APIs with dynamic inputs, such as running the same workflow for multiple users, IDs, or configurations.

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Using a Data File in Collection Runner

Follow these steps to run a collection with custom data:
1

Open Collection Runner

In the Collections sidebar, find the collection you want to execute and click the Run icon next to it.Requestly Collection Runner interface showing how to open and run an API collection from the Collections sidebar or Runner tab.
2

Select a Data File

In the Runner configuration panel, click Select Data File.
Supports JSON & CSV files (max 100MB)
Runner configuration panel in Requestly showing the Select Data File option to upload a CSV or JSON file for data-driven API testing.Once added, Requestly will automatically detect the file type and preview its structure.
3

Preview Data and Map Variables

After selecting the file, a preview of your data will appear.
  • For CSV files: verify column names and types
  • For JSON files: check object keys and structure Requestly data preview screen displaying CSV and JSON structures, allowing users to verify columns, keys, and map variables like city or user_id.
Each key or column name should match the variable used in your requests, such as {{city}} or {{user_id}}.
4

Start the Run

Click Save and then Start Run.
The Collection Runner will replace variables with data from your file for each iteration.Requestly Collection Runner executing an API collection with data variables replaced from the selected CSV or JSON file.

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How Data Files Work

When you attach a CSV or JSON file to your manual run:
  • Each row (CSV) or object (JSON) represents one iteration
  • Variables inside your requests (like {{name}} or {{email}}) are replaced with the corresponding values
  • Requestly automatically cycles through each data set until all iterations are complete

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Supported File Formats

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CSV Format

  • The first row defines variable names
  • Each subsequent row represents one iteration
  • Each row must have the same number of columns
Example: 
city,temperature  
Vancouver,10  
Austin,24  
London,12

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JSON Format

  • Must be an array of key-value objects
  • Each object defines one iteration
Example: 
[  
  { "city": "Vancouver", "temperature": 10 },  
  { "city": "Austin", "temperature": 24 },  
  { "city": "London", "temperature": 12 }  
]

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Example Use Case

For a request like 
GET https://api.example.com/weather?city={{city}}
and a data file containing 
city
Vancouver
Austin
London
Requestly will automatically replace {{city}} with each value during the run.