Windows · Guide
How to Send Your First API Request with Postman on Windows
Short answer
Install Postman for Windows, create a request, choose the HTTP method, paste the endpoint URL, add any headers or auth, and click Send. Save it into a collection so you can rerun it later.
Requirements
- Windows 11 or Windows 10
- Postman for Windows (free tier)
- An API endpoint and, if required, an API key
- Optional: Insomnia as a lighter alternative
Steps
1. Install Postman
Download the Windows installer from postman.com. It installs per user, so administrator rights are usually not needed.
2. Create a workspace and collection
Collections group related requests. Creating one before your first request saves reorganising later, and it is what you export to share with teammates.
3. Build the request
Click New > HTTP Request, set the method to GET, and paste the endpoint URL. Query parameters typed into the URL appear automatically in the Params tab.
4. Add authentication
Open the Authorization tab and pick the scheme the API documents — Bearer Token, Basic Auth or API Key. Postman adds the header for you rather than you typing it.
5. Send a POST body
Switch the method to POST, open Body > raw, and choose JSON. Postman sets Content-Type: application/json, which is the most common cause of a manual request failing.
6. Read the response properly
Check the status code and time first, then Headers, then the body. A 401 is credentials, 403 is permissions, 404 is the wrong path, and 422 usually means a malformed body.
7. Move secrets into environment variables
Create an environment with variables such as base_url and api_key, then reference them as {{api_key}}. Your collection stays shareable without exposing a live key.
Alternative methods
1. Use Insomnia
Insomnia covers the same ground with a lighter interface and no sign-in requirement, which suits people who only need a local client.
2. Use curl from the terminal
curl ships with Windows 10 and 11. Postman can generate the equivalent curl command through Code snippet, which is ideal for pasting into documentation.
Troubleshooting
Postman cannot reach a localhost service
Confirm the port with netstat, and remember that a service inside WSL 2 or a container may need its port forwarded before Windows can reach it.
SSL certificate errors on an internal API
For a self-signed development certificate, turn off SSL verification in Settings for that workspace only, and never for third-party production APIs.
The API works in the browser but not in Postman
The browser is sending a session cookie you do not have. Copy the required cookie or authorisation header from the browser developer tools into your request.
Frequently asked questions
Is Postman free?
The free tier covers individual API work, with paid plans for larger collaboration limits. A Postman account is required for cloud sync features.
Can I use Postman offline?
Yes, requests run locally, but collections created while signed out stay on that machine until you sign in and sync them.
Does Postman store my API keys in the cloud?
Synced environments are stored in your Postman account. Keep production secrets in local-only environments or use secret variables if that matters to you.
How do I share a collection?
Export the collection as JSON and commit it to your repository, or share it through a Postman workspace if everyone involved has an account.