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Authorization

Follow this guide to create a new FastBill credential that will allow Nexla to authenticate to and exchange data with your FastBill account.
fastbill_api_auth.png

FastBill

Prerequisites​

The FastBill connector uses HTTP Basic Authentication, pairing your FastBill account email address with an API key as the password. Before creating a credential in Nexla, you will need to locate or generate your FastBill API key.

Locate Your FastBill API Key​

FastBill provides an API key for each account, which is used alongside your login email to authenticate all API requests.

  1. Log in to your FastBill account at my.fastbill.com.

  2. Navigate to your account settings. You can access this by clicking on your name or avatar in the upper-right corner and selecting Settings (Einstellungen).

  3. Scroll to the bottom of the Settings page. Your API key is displayed in the API section. Copy this value for use in the Nexla credential configuration.

    For FastBill Next accounts, the API key is found under Settings > Interfaces > API-Key. The key is tied to your account and does not expire unless you regenerate it. Keep this key secure — anyone with your email and API key can access your FastBill data via the API.

  4. Note the FastBill Classic API base URL: https://my.fastbill.com/api/1.0/api.php. All API calls are made to this single endpoint, with the requested service specified in the JSON request body.

    Additional documentation on the FastBill API is available at the FastBill API Documentation and FastBill Support — FastBill API.

Create a FastBill Credential​

  • To create a new FastBill credential, after selecting the data source/destination type, click the Add Credential tile to open the Add New Credential overlay.

Credential Name & Description​

  1. Enter a name for the credential in the Credential Name field and a short, meaningful description in the Credential Description field.

    Resource descriptions are recommended but are not required. They should be used to provide information about the resource purpose, data freshness, etc. that can help the owner and other users efficiently understand and utilize the resource.

API Key Authentication​

FastBill authenticates API requests using HTTP Basic Authentication, with your account email address as the username and your FastBill API key as the password. All requests are sent as JSON-body POST calls to a single base URL.

  1. Enter your FastBill account email address in the Account Email field. This is the email you use to log in to FastBill and serves as the HTTP Basic Auth username for all API requests.

  2. Enter your FastBill API key in the API Key field. This key acts as the HTTP Basic Auth password and is used to authenticate every request Nexla makes to the FastBill API. Keep this value secure and do not share it.

  3. The Base URL field is pre-populated with https://my.fastbill.com/api/1.0/api.php, which is the standard endpoint for the FastBill Classic API. All services — invoices, customers, expenses, time entries, and more — are accessed by POSTing to this single URL with a SERVICE field in the JSON request body. You should only change this value if directed to do so by FastBill support.

Save the Credential​

  1. Once all of the relevant steps in the above sections have been completed, click the Save button at the bottom of the overlay to save the configured credential.

  2. The newly added credential will now appear in a tile on the Authenticate screen during data source/destination creation and can be selected for use with a new data source or destination.