In order for Blinksale to work correctly with your Basecamp (currently only servicing Basecamp classic) account from 37signals, we need to know your Basecamp URL as well as your API token. According to these instructions, your API token can be found by logging into your Basecamp account, clicking on the "My Info" link in the upper-right, and then clicking the "Show your tokens" at the bottom (under "Authentication tokens"). We do not share this information with anyone.
When you click Save Settings, we'll check to make sure your Basecamp information works. If it does, then you can start creating invoices for your clients in Basecamp immediately. Simply click the New Invoice button as you normally would, then choose the "Import from Basecamp" option for the pull-down menu. You can then select a client from Basecamp to create an invoice for. After you import a client from Basecamp for the first time, that client is permanently added to your Blinksale client list.
Below that will be a box that asks for your Blinksale URL (i.e. blinksale.basecamphq.com). (Enter the Basecamp site address that you use to access your Basecamp account, and with its correct .com address (i.e., yourcompanyname.projectpath.com). Please note that you do not need to enter http:// in this field.)
And then enter your Basecamp API token. Please note that Blinksale can only access Basecamp information that this token has permission to access. If you regenerate your API token, please update here as well.
Enable Basecamp API Access
One last thing: In order for Blinksale to access your Basecamp data, you must enable API access to your Basecamp account. You may enable API access to your Basecamp account by selecting that option on your Basecamp account page. If you do not do this, Blinksale will not be able to import your data from Basecamp.