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FastBill API Authentication

How to authenticate FastBill API requests: one Bearer API key plus a connectionId. MindCloud stores your FastBill credentials — no auth headers to build.

Every FastBill API request through MindCloud needs two things: a MindCloud API Key and a connectionId for your FastBill account. This page covers both, plus exactly how to send them, so you do not need to visit any other page to get authenticated.

Steps to authenticate

  1. Create a MindCloud account at app.mindcloud.co if you do not already have one.
  2. Generate a MindCloud API Key in API Keys. This is the Bearer token you send on every request. Keep it on your server.
  3. Create a FastBill connection in Connections. FastBill uses a username and password. You enter them when you create the connection — MindCloud stores them securely so your requests never carry raw credentials.
  4. Copy the connection’s connectionId — you will send it on every request alongside your MindCloud API Key.

How requests are authenticated

Authentication has two layers. Your MindCloud API Key authenticates the request to MindCloud, sent as a Bearer token in the Authorization header. The connectionId selects the connected FastBill account that should run the action. MindCloud stores and refreshes the FastBill credentials behind that connection, so you never send provider tokens with your requests.

Pass connectionId in the query string for GET and DELETE actions, and in the JSON body for POST, PUT, and PATCH actions.

For example, calling with an FastBill connection looks like this:

The Authorization: Bearer <your MindCloud API Key> header authenticates you to MindCloud; the connectionId tells MindCloud which FastBill account to run the action against. Missing or invalid Authorization returns 401, and a missing or mismatched connectionId returns 400.

Find Your FastBill API Credentials

You need access to the main FastBill user account.

  1. Sign in to FastBillFastBill
  2. Open Settings and Overview

    In FastBill, go to Settings and open the Overview page.

    Settings → Overview

  3. Copy the main user email address

    Use the main FastBill user's email address as the username in MindCloud.

  4. Copy the API key

    On the Overview page, find the API Key and paste it into the API Key field in MindCloud.

Keep your key safe

Keep your MindCloud API Key on your server; do not ship it in browser code, mobile apps, public repositories, or logs. Anyone with the key can call the Universal API as your MindCloud account, across every connection you have created.