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Postman is a free application that lets you build, send, and inspect HTTP requests through a visual interface. Instead of assembling curl commands by hand, you fill in the URL, headers, and body in a form, hit Send, and see the full response — status code, headers, and body — right in the app. For the Portal.io API, Postman is especially useful because every request requires HMAC-SHA256 signature headers. The Portal.io Postman collection includes pre-configured requests and a built-in pre-request script that computes signatures automatically, so you can focus on understanding the API rather than debugging authentication.

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Why use Postman with the Portal.io API

Portal.io’s HMAC authentication means every request needs five headers and a correctly assembled signature. Getting any piece wrong produces a 401 with no detail about what failed. Postman eliminates that friction during development:
  • Pre-built requests — every Portal.io API endpoint is already set up with the right method, URL, headers, and sample body. You just fill in your credentials.
  • Automatic HMAC signing — the collection’s pre-request script builds the canonical message and computes the Base64-encoded HMAC-SHA256 signature on every send. No manual signature work needed.
  • Instant feedback — see the full response (status, headers, JSON body) immediately. Compare what you expect with what the API actually returns.
  • Environment variables — store your Application Key, Secret Key, and User Key once, and they apply to every request in the collection.

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Get the collection

Run in Postman

Import the Portal.io API collection directly into your Postman workspace.
If you prefer to import manually, copy this link and use Import → Link in the Postman app: 
https://god.gw.postman.com/run-collection/22981260-7030cfc9-3a53-4f6a-b4b9-0560e8514aec

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Set up your environment

After importing the collection, create a Postman environment with the following variables. These are referenced by the collection’s pre-request script and request templates.
VariableValueWhere to get it
appIdYour API Application KeyProvided by your Portal.io representative
secretKeyYour Secret KeyProvided by your Portal.io representative
userKeyYour User API KeyReturned by the credential exchange endpoint (see quickstart)
baseUrlhttps://sandbox.api.portal.ioUse https://api.portal.io for production
Run the API Key Exchange request in the collection first. It returns your User Key, which you can copy into the userKey environment variable. After that, every other request in the collection will authenticate automatically.

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Make your first request

Once your environment variables are set:
  1. Select the List Proposals request from the collection sidebar.
  2. Confirm the environment dropdown (top right) is set to the environment you just created.
  3. Click Send.
You should see a 200 response with a JSON body containing your proposals array. If you get a 401, double-check that your appId, secretKey, and userKey variables are set correctly and that you selected the right environment.

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Tips for working with the collection

  • Duplicate before customizing. If you want to modify a request (add query parameters, change the body), duplicate it first so the original stays intact for reference.
  • Check the console. Open the Postman Console (View → Show Postman Console) to see the exact request that was sent, including the computed signature. This is invaluable when debugging authentication issues.
  • Switch environments for production. Create a second environment with your production credentials and baseUrl set to https://api.portal.io. Switching between sandbox and production is a single dropdown change.

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Installing Postman

If you don’t have Postman installed, download the free desktop app from postman.com/downloads. Postman is available for macOS, Windows, and Linux. There is also a web version at go.postman.co that works in any browser — no installation required.