Before you can test an API, you need one. Let Agent Mode build it.
Create Your Workspace
Every testing project starts with a workspace to keep your collection, requests, and results organized. You'll create one by hand through Postman's UI — the same flow you'd use for any real project.
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Open Postman (desktop app or web) and sign in.
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Click Workspaces in the Postman header, then click Create.
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On the Create your workspace form, name it exactly, replacing
[Your Name]with your own name:[Your Name] - API Testing -
For Who can access, open the dropdown and choose Only you and invited people — Internal is already selected.
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Leave the template on Blank workspace (already selected), then click Create Workspace.
Build the Movies API Collection
Now bring in Agent Mode — Postman's AI assistant that completes tasks from natural-language prompts, like scaffolding requests and writing tests. Open it from the panel in the bottom-right corner of your workspace (switch to the AI tab), or type > followed by Agent Mode in the universal search input at the top of the app.
A note on approvals: Agent Mode shows you what it's about to do and asks for confirmation before it changes anything — so you stay in control. If you've enabled Auto-run, it applies those actions without prompting. Either way, read what it proposes before you move on.
Rather than click through the request builder by hand, describe the whole API in plain English and let Agent Mode scaffold every request for you. The Movies API has five endpoints:
| Method | Endpoint | Description |
|---|---|---|
| GET | /movies/animation | List all animated movies |
| GET | /movies/animation/:id | Get one movie |
| POST | /movies/animation | Create a movie |
| PUT | /movies/animation/:id | Update a movie |
| DELETE | /movies/animation/:id | Delete a movie |
A movie has an id (number), title (string), posterURL (string), and imdbId (string).
Make sure you're in your [Your Name] - API Testing workspace, then run a prompt like:
Create a collection called "Movies API" in this workspace. Add a request for each of these endpoints: GET /movies/animation, GET /movies/animation/:id, POST /movies/animation, PUT /movies/animation/:id, DELETE /movies/animation/:id. Use https://api.sampleapis.com as the base URL. For the PUT and DELETE requests, set the id path variable to 1 so their URLs are valid and ready to send. For POST and PUT, include an example JSON body with id, title, posterURL, and imdbId.
Review the requests Agent Mode creates, then approve them — or, with Auto-run enabled, confirm the changes it applied.
See it for yourself: Open the GET /movies/animation request and click Send. You should get a 200 OK and a JSON array of movies in the response pane — proof the request reaches the API before you start testing it.
A note on the practice API: GET requests return real data, but POST, PUT, and DELETE echo your input back without persisting it. That's a useful lesson in itself — you test what an endpoint promises, and part of testing is knowing what your API actually does. Where the sandbox differs from a production API, the steps below say so.