What are Global, Environment, and Collection variables in Postman?

Postman has 5 variable scopes listed from highest to lowest priority:

Local > Data > Environment > Collection > Global

When variables share the same name, the higher-priority scope wins.

1. Global Variables

• ✓Available across all workspaces, collections, and environments
• ✓Useful for values shared across everything
• ✓Set in: Environments → Globals

// Set global variable in script
pm.globals.set("global_token", "abc123");

// Get global variable
const token = pm.globals.get("global_token");

2. Environment Variables

• ✓Available within the selected environment only
• ✓Ideal for: base URLs, API keys, user credentials per environment
• ✓Change by switching the active environment

pm.environment.set("base_url", "https://api.staging.com");
const url = pm.environment.get("base_url");

3. Collection Variables

• ✓Scoped to a specific collection
• ✓Good for variables shared across all requests in a collection

pm.collectionVariables.set("user_id", "123");
const id = pm.collectionVariables.get("user_id");

4. Data Variables

• ✓Come from external CSV or JSON files used in Collection Runner
• ✓Only available during a collection run
• ✓Example CSV row: username,password

5. Local Variables

• ✓Only available in the current script execution (Pre-request or Test)
• ✓Highest priority but temporary

pm.variables.set("temp_value", "xyz");
const val = pm.variables.get("temp_value");