Skip to main content
Connect Cal.com to Retell with OAuth or an API key to give your agents live appointment tools. One workspace-level connection can be used by multiple agents, so you don’t enter credentials in each tool.
This integration replaces Retell’s built-in Cal.com availability and booking tools. The dashboard no longer offers them, the API stops creating and updating them on 09/30/2026, and on 10/31/2026 Retell migrates the ones you already have to this integration. Read the deprecation notice before then: a tool whose Cal.com key has expired isn’t migrated and stops working.

​
When to use it

Connect Cal.com when your scheduling runs on it and you want callers handled end to end. It’s the right choice when you want to:
  • Read live openings to the caller. The agent checks the event type’s slots and offers actual times.
  • Book while the caller is on the line. After the caller confirms a time, the agent books it and Cal.com sends its usual confirmations.
  • Reschedule and cancel existing bookings. The agent finds the caller’s booking by email and moves it to a newly confirmed slot, or cancels it.
For example, a dental clinic’s inbound agent looks up tomorrow’s cleaning by the caller’s email, offers the week’s open slots, and moves the appointment to Friday 10am, all in one call.

​
Prerequisites

  • A Cal.com account with access to the event types you want to book.
  • An event type with open hours and a connected calendar for checking busy times. See find an event type ID.
  • Know whether your account is on cal.com or cal.eu (the EU-hosted instance). OAuth supports cal.com; API keys support either instance.
Cal.com has announced that cal.eu shuts down on November 1, 2026; enterprise customers keep access through their contracted term. Migrating to cal.com is opt-in. If you migrate, create a connection with the Cal.com domain using OAuth or a cal.com API key.

​
Which connection method should I use?

Both methods use the same agent tools. Existing API key connections keep working and aren’t automatically changed to OAuth.

​
Connect with OAuth

1

Add the connection

In the Retell Dashboard, open Integrations, select the Available tab, find Cal.com, and click Connect (Add Account if a connection already exists).
2

Choose OAuth and a domain

Select OAuth. Keep the default connection name, Cal.com - OAuth, or choose a name that identifies the account. In Domain, select Cal.com.
Retell's Cal.com connection dialog with OAuth selected as the suggested method, the connection name Cal.com - OAuth, Domain showing Select a domain, and Continue with Cal.com disabled.

Choose OAuth, then select Cal.com in Domain to continue.

3

Authorize Retell in Cal.com

Click Continue with Cal.com. Sign in to the Cal.com account the agents should use, review the requested permissions, and approve access. Cal.com redirects you back to Retell.You don’t need to create your own OAuth client or enter a client ID, client secret, or callback URL.
4

Verify the connection

Confirm the connection appears on the Connected tab. Then add Cal.com tools to an agent and run a live availability check to verify access to your event type.

​
Connect with an API key

1

Create a key in Cal.com

On the Cal.com instance you use, go to Settings > Developer > API keys and click + New. Keep the API key tab selected, name the key Retell AI, and turn on Never expires. Create it and copy it right away; Cal.com shows the key only once. An expiring key stops working on its expiry date.
Cal.com's Create an API key dialog on the API key tab, with an empty Name this key field, Never expires switched on and outlined in blue, and Cancel and Create buttons.

Cal.com's Create an API key dialog, with Never expires turned on.

2

Enter the key and domain

In Retell, open Integrations, find Cal.com, and click Connect or Add Account. Select API key.Fill in the fields:
Retell's Cal.com connection dialog with API key selected, the connection name Cal.com - API key, an empty API Key field, Domain showing Select a domain, and Add Account disabled.

Choose API key, then enter a key and select its domain.

Click Connect (Add Account if a connection already exists). Retell tests the key against the Cal.com API.
3

Verify it worked

On success the connection appears on the Connected tab. Your agents can now book against the account — see Cal.com agent functions for the tools and the event type ID the booking tools need.

​
Troubleshooting

For OAuth, use a cal.com account, approve the requested permissions, and complete the redirect back to Retell. If you cancelled authorization, start again from the connection’s Reconnect button.For an API key, confirm the key is current and Domain matches the instance where you created it. If the key had an expiry date, it may have lapsed.
Open the connection’s settings on the Connected tab. For OAuth, click Reconnect and authorize Retell again. Retell normally refreshes access tokens automatically, so routine token expiry doesn’t require you to reconnect.For an API key, paste a fresh key set to never expire and click Reconnect.

​
FAQ

No. The OAuth connection supplies the credentials for the tools. You don’t need to create or paste an API key. See permissions for the access Retell requests.
Add a new OAuth connection, then add replacement functions from that connection in the agent editor. Update the flow nodes or prompt to use those functions. Existing functions stay bound to their original connection.
No. The connection targets Cal.com’s hosted API on cal.com or cal.eu; self-hosted instances aren’t supported (as of August 2026).

​
Next steps

Cal.com agent functions

Check availability, book appointments, and reschedule or cancel bookings mid-conversation.

Integrations overview

See every provider Retell connects to and how integration tools work.

Connect Calendly

The other calendar option, if your scheduling lives there.