Viktor
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Learn how to set up and get the most out of Viktor.

Custom Integrations

Connect an app that isn't in the catalog: add any REST API with your credentials, or connect a remote MCP server by its URL.

If an app isn't in the catalog, you can still connect it. There are two kinds of custom integration:

  • API: any REST API, described once (base URL, methods, credentials) so Viktor can call it.
  • MCP Server: a remote MCP (Model Context Protocol) server, connected by its URL. It brings its own tools.

You can add a Custom API yourself from the web, or ask Viktor to set it up for you in chat.

Add a Custom API from the web

  1. On Integrations, select Add Custom.
  2. In Add Custom Integration, choose API and select Next.
  3. Fill in the form:
  4. - Name
  5. - Base URL: requests are made relative to this URL. It must start with https://, and it can't include a query string, a fragment, or a username and password.
  6. - Allowed methods: any of GET, POST, PUT, PATCH and DELETE. Pick at least one.
  7. - Authentication: Bearer token (enter the API token) or API key (enter the Header name that carries the key and the API key).
  8. - Documentation URL (optional)
  9. Select Add API.

Viktor gets one tool per allowed method for this API, and you can set each one's level on the account's Tools tab. See Integration permissions.

Edit a Custom API

  1. Open the API's account and go to Settings.
  2. Under API configuration, select Edit API.
  3. Change what you need and select Save changes.

Stored secrets are never shown in the form. Leave the token or key blank to keep the current one. If you change the authentication type, a warning reminds you that this replaces the stored credential, so enter the new one.

Have Viktor set up a Custom API in chat

Ask Viktor to connect an API that isn't in the catalog. He checks the catalog first, then:

  1. Reads the API's documentation and creates the Custom API for you. Besides bearer tokens and header keys, he can set up basic auth, a key in a query parameter, and HMAC request signing.
  2. Sends you a secure link to a page titled Connect {name}, which shows the base URL, the methods and when the link expires.
  3. You sign in, enter the credentials and select Save. The page confirms Connected: Credentials saved for {name}.

The conversation then continues, and Viktor can call the API. The link expires 24 hours after Viktor creates it. Viktor stores only what you enter there, and uses it only to authenticate requests for this integration.

Delete a Custom API

  1. Open the API's account and go to Settings.
  2. Select Delete Custom API.
  3. Confirm with Delete.

This permanently deletes the API's configuration and stored credentials, and removes its tools. It can't be undone.

A Custom API has no Add another account and no Reconnect. To change credentials, edit it instead.

Connect a remote MCP server

  1. On Integrations, select Add Custom.
  2. Choose MCP Server and select Next.
  3. Enter the Server URL, including https://, and select Connect.
  4. Give the connection a nickname and, in Slack or Microsoft Teams workspaces, choose who can use it. This is the same dialog as for a catalog app. See Connect your tools.
  5. Viktor detects how the server authenticates. If it uses its own sign-in, you sign in through the browser. If it needs an API key, a page asks you for the key. If it needs neither, it connects directly.

Only remote MCP servers that are reachable over HTTPS are supported. Local MCP servers running on your machine aren't. The dialog links to the Awesome Remote MCP Servers list if you're looking for servers to try.

Limits

  • Permission: if an admin turned off Connect new integrations, members can't select Add Custom, and the server refuses new Custom APIs from members with Adding integrations is restricted to admins. See Integration permissions.
  • Delete: the person who added the Custom API, or an admin. While it's locked, admins only.
  • Edit: Edit API only shows for people allowed to edit that API.
  • Custom API authentication on the web: only bearer token and header API key. For other methods, ask Viktor in chat.

Common problems

  • "Enter a valid HTTPS MCP server URL": the URL isn't a full https:// address. Copy the server's MCP endpoint, not the provider's website.
  • "This URL does not include "mcp"": a warning, not an error. Some servers use other paths, but check that you copied the server endpoint rather than a website or an OAuth URL.
  • "Zapier MCP is not supported at this time.": Zapier's MCP server can't be added as a custom server.
  • The secure credentials link doesn't work: it expired. Ask Viktor for a new one.
  • You need an app that isn't in the catalog and has no API: contact support. See Request a new integration.

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