Write the request once, run it anywhere
Hardcoded values are what make an API collection brittle. A base URL baked into forty requests means forty edits every time you point at staging.
Define the value once
A variable is a named placeholder. Define base_url as api.example.com and user_id as 123, then write your request as https://{{base_url}}/users/{{user_id}}.
Pick the right scope
Not every value belongs in the same place. Environment variables change between dev, staging and production.
When the same name appears in more than one scope, a documented precedence order decides which value wins, so the behaviour is predictable rather than surprising.
Check it before you send
Hover over any {{variable}} in a request and Requestly shows you the value it will resolve to. It is a small thing that removes most of the guesswork from a misfiring request.
