Caddi connects to RelativityOne through an OAuth2 client you create inside your own Relativity instance. Your Relativity system administrator creates the client and supplies the credentials — Relativity support is not normally involved.
Before you start
You'll need:
A Relativity system administrator account with full permissions on Authentication Provider Type, Authentication Provider, Login Method, and OAuth2 Clients
The Application Management feature permission on your admin group, or the OAuth2 Client tab won't be visible
Owner or Admin access to your Caddi organization
Your RelativityOne instance host — read it from your browser address bar when signed in
Step 1: Create the OAuth2 client in Relativity
Sign in to Relativity as a system administrator and switch to the admin (Home) workspace context.
Two things cannot be undone. The Flow Grant Type is fixed once you save — if you pick the wrong one you must create a new client. And the Client Secret is shown only once; if you lose it, use Reset Secret and update Caddi with the new value.
Open the Authentication section and go to the OAuth2 Client tab.
Click New OAuth2 Client.
Name — enter something unique and identifiable, for example
Caddi.Flow Grant Type — select Code. This is the authorization-code flow Caddi uses.
Redirect URLs — enter
https://app.trycaddi.com/oauth-callback, including thehttps://prefix.Access Token Lifetime — enter a value in minutes. 60 is a reasonable starting point.
Allow Refresh Tokens — enable this. Without refresh tokens, users will have to reconnect every time the access token expires.
Trusted IPs — leave blank unless your firm requires IP restrictions. See the note below if you set them.
Click Save. Relativity generates the Client ID and Client Secret.
Copy the Client Secret now.
Step 2: Configure RelativityOne in Caddi
This step must be completed by a Caddi organization owner or admin.
In Caddi, open Integrations in the left sidebar, then click the Integration Setup tab at the top of the page. This tab is only visible to organization owners and admins.
Find RelativityOne in the list and click Configure.
Enter the following values:
Client ID — from the OAuth2 client you created
Client Secret — the value shown once at creation
Instance URL — your RelativityOne host, for example
https://acme.relativity.one
Click Save Configuration. Caddi validates the credentials immediately — if something is wrong you'll see an error right away, and nothing is stored until validation passes.
Step 3: Connect your account
Go back to the My Connections tab and find RelativityOne.
Click Connect + and sign in to Relativity.
You'll be returned to Caddi with the connection active.
How the connection behaves
Each user connects their own Relativity account. Relativity OAuth2 clients have no scope model — Caddi's access is exactly what the connecting Relativity user's workspace and object permissions allow. To widen or narrow access, change those permissions in Relativity.
Access token lifetime is whatever you set on the client. A short lifetime combined with refresh tokens disabled will break long-running loops.
Trusted IPs apply to Caddi's traffic. If you populate that field and Caddi's egress addresses aren't listed, requests fail with an HTTP 400. Changes take up to five minutes to propagate. Contact Caddi support for the current address list.
Revoking access. Delete the OAuth2 client, or use Reset Secret without updating Caddi.
Troubleshooting
The OAuth2 Client tab isn't visible in Relativity
Your admin group is missing the Application Management feature permission, or the OAuth2 Client object permissions. Some RelativityOne tenants also restrict admin tabs by contract — if permissions look right, open a Relativity support ticket.
Requests fail with HTTP 400 shortly after setup
A Trusted IPs value is set and doesn't include Caddi's egress addresses. Either clear the field or add Caddi's addresses, then wait up to five minutes.
Users are prompted to reconnect frequently
Allow Refresh Tokens is disabled on the OAuth2 client, or the Access Token Lifetime is very short. Edit the client and enable refresh tokens.
A redirect error at sign-in
The Redirect URLs value is missing the protocol prefix or doesn't match https://app.trycaddi.com/oauth-callback exactly.
Still stuck? Contact Caddi support with the exact error message you're seeing and the time it occurred.
Automation ideas
Law Firms
New matter → workspace provisioning
When a litigation matter opens, Caddi creates the Relativity workspace from your firm's template, applies the standard groups and permissions, and records the workspace reference back on the matter.
Review milestone → status reporting
Caddi pulls review progress and document counts on a schedule and drafts the client or partner status update, so nobody rebuilds it by hand each week.
Production complete → matter file and log
When a production finishes, Caddi files the production log to the matter record in your DMS and logs the activity in your practice management system.