Flows Host App API

Interaction methods available on the HostAppAPI instance returned by connectToHostApp. Use these to navigate within or outside of Cognite Data Fusion (CDF), persist shareable app state, hide or show the CDF sidebar (the shell), and integrate with the AI agent panel. For connecting and getting credentials, see Auth API.

Prerequisites

A Flows custom app created with npx @cognite/cli@latest apps create
A HostAppAPI instance from connectToHostApp. See Auth API.

navigateInternal

Navigates to a path within CDF.

await api.navigateInternal({
  path: "/my-other-app",
  queryParams: { tab: "overview" },
});

Parameter	Type	Description
`path`	`string`	CDF-relative path to navigate to
`queryParams`	`Record<string, string>` (optional)	Query parameters
`hash`	`string` (optional)	URL hash fragment
`openInNewTab`	`boolean` (optional)	Open in a new tab instead of navigating the current tab

navigateExternal

Opens an external URL.

await api.navigateExternal({
  url: "https://docs.cognite.com",
  openInNewTab: true,
});

Parameter	Type	Description
`url`	`string`	HTTPS URL to navigate to
`openInNewTab`	`boolean` (optional)	Open in a new browser tab

State

syncInternalState

Saves a serialized state string to the customAppInternalState URL search param. The saved state is passed back as initialState the next time the app mounts. Users can return to the same view after navigating away or refreshing. Because the state lives in the URL, the link is shareable.

const handled = await api.syncInternalState(
  JSON.stringify({ view: "dashboard", assetId: "12345" })
);

Parameter	Type	Required	Description
`state`	`string`	Yes	JSON-serialized state. Must be a string. Call `JSON.stringify` before passing.

Return type	Description
`Promise<boolean>`	`true` if the host saved the state; `false` if the host did not handle the call (for example, in standalone dev mode).

See App state in URLs for a full guide covering state restoration, what to include in persisted state, and a complete example.

Layout

setHideShell

Hides or reveals the CDF sidebar for the current page, maximizing your app on the page.

await api.setHideShell(true);  // hide the sidebar
await api.setHideShell(false); // show the sidebar again

Parameter	Type	Required	Description
`hidden`	`boolean`	Yes	`true` to hide the sidebar; `false` to show it again.

setHideShell only takes effect when your app is loaded on a custom apps route (/custom-apps/…). Calling it from any other route is a no-op for sidebar visibility. Requires @cognite/app-sdk 0.9.0 or later.

Example: maximize your app on the page

import { connectToHostApp } from "@cognite/app-sdk";

const { api } = await connectToHostApp();

// Hide the sidebar to maximize the app on the page
await api.setHideShell(true);

// Show the sidebar again when done
await api.setHideShell(false);

Fullscreen

Flows custom apps run inside a browser iframe that has the fullscreen feature policy enabled. This means your app can request the browser’s native fullscreen mode using the standard Fullscreen API; no additional configuration required.

// Enter fullscreen
await document.documentElement.requestFullscreen();

// Exit fullscreen
await document.exitFullscreen();

Use setHideShell in Layout when you want to hide the CDF sidebar and maximize your app within the page. Use the browser Fullscreen API when you need to take over the entire display (for example, for a media viewer or a 3D scene).

Agent

Control the CDF AI agent panel and unregister an agent server from your app. For parameters, examples, and the full workflow (registering a server, resources, and actions), see Integrating AI agents with Flows.

sendAgentLayoutMode

Changes the visibility or layout of the agent panel (sidebar, fullscreen, or closed).

sendAgentMessage

Injects text into the agent chat. Optionally starts a fresh session. Open the panel with sendAgentLayoutMode first so the user sees the message.

unregisterAgentServer

Unregisters an agent server previously registered with registerAgentServer from @cognite/app-sdk. Call this when your app unmounts.

Build

Prerequisites

Navigation

navigateInternal

navigateExternal

State

syncInternalState

Layout

setHideShell

Example: maximize your app on the page

Fullscreen

Agent

sendAgentLayoutMode

sendAgentMessage

unregisterAgentServer

Further reading

​Prerequisites

​Navigation

​navigateInternal

​navigateExternal

​State

​syncInternalState

​Layout

​setHideShell

​Example: maximize your app on the page

​Fullscreen

​Agent

​sendAgentLayoutMode

​sendAgentMessage

​unregisterAgentServer

​Further reading

Prerequisites

Navigation

navigateInternal

navigateExternal

State

syncInternalState

Layout

setHideShell

Example: maximize your app on the page

Fullscreen

Agent

sendAgentLayoutMode

sendAgentMessage

unregisterAgentServer

Further reading