Basecamp connects to Caddi through an app that you register with 37signals Launchpad. Registering the app gives you a Client ID and Client Secret, which you enter in Caddi.
Before you start
You'll need:
A Basecamp account
Owner or Admin access to your Caddi organization
Step 1: Copy the redirect URL from Caddi
In Caddi, open Settings, then Integrations.
Under Connectors you can configure, find Basecamp - Custom OAuth App and click Configure.
Click Copy redirect URL. The redirect URL is
https://app.trycaddi.com/oauth-callback.
Keep this form open. You'll come back to it in Step 3.
Step 2: Register an app in 37signals Launchpad
Go to launchpad.37signals.com/integrations and sign in with your Basecamp account.
On the Your Applications page, click Register another application. If you have no applications yet, the button is labeled Register one now.
Fill in the app name, your company name, and your company website.
Under Products, select Basecamp (the current version, not Basecamp 2 or Basecamp Classic).
In the redirect URI field, paste the redirect URL you copied in Step 1.
Click Register this app.
Back on Your Applications, click the name of the app you just registered.
In the OAuth 2 section, copy the Client ID and Client Secret.
Do not send this secret by email, chat, or a support ticket. Paste it straight into Caddi in Step 3, or keep it in a password manager until you do.
Step 3: Add the app credentials in Caddi
Return to the Basecamp - Custom OAuth App Configure form from Step 1. If you closed it, open Settings, then Integrations, and under Connectors you can configure, find Basecamp - Custom OAuth App and click Configure.
Paste the Client ID into Client ID.
Paste the Client Secret into Client Secret.
Click Save Configuration.
Step 4: Confirm the connection
In Caddi, open Integrations in the left sidebar.
Find Basecamp - Custom OAuth App and click Connect.
Sign in to Basecamp and approve the request. You'll be returned to Caddi with the connection active.
If you're not going to be an everyday user of Caddi, you can disconnect after confirming the connection works.
Sources
Authentication — Basecamp API docs
