cometchat-native-core

Purpose

This is the foundational skill for every CometChat React Native UI Kit v5 integration. It teaches Claude HOW CometChat works on RN — initialization order, provider wrapper chain, login, env vars, auth tokens, and the anti-patterns that break real apps.

Read this skill first, before any framework (cometchat-native-expo-patterns / cometchat-native-bare-patterns) or placement skill.

Ground-truth sources: docs/ui-kit/react-native/overview.mdx, react-native-cli-integration.mdx, expo-integration.mdx, methods.mdx, and @cometchat/chat-uikit-react-native@5.3.8's src/index.ts (file-based initFromSettings GA). Official docs: https://www.cometchat.com/docs/ui-kit/react-native/overview · Docs MCP: claude mcp add --transport http cometchat-docs https://www.cometchat.com/docs/mcp (or fetch the URL directly without MCP).

---

1. The init-login-render order

CometChat has exactly one valid lifecycle on React Native:

CometChatUIKit.init(settings)   →   CometChatUIKit.login({ uid })   →   render <CometChat*> components

Breaking this order produces a blank screen, a "CometChat is not initialized" runtime error, or a hung login. No exceptions.

File-based init with cometchat-settings.json (recommended)

Version requirement (ENG-35866 — Skills Telemetry). CometChatUIKit.initFromSettings(settings) reads a cometchat-settings.json object and lets the SDK self-report integrationSource = "ai-agent" to /user_sessions. It ships GA in @cometchat/chat-uikit-react-native >= 5.3.8 + @cometchat/chat-sdk-react-native >= 4.0.25 (npm latest). On an older UI Kit the method does not exist — use the flat-object init() fallback below.

Step 1 — create cometchat-settings.json at the project root. Fill appId / region / credentials.authKey from the CLI provision setup output; leave everything else at the defaults below. Single source of credentials — no second copy to keep in sync.

{
  "appId": "APP_ID_HERE",
  "region": "us",
  "credentials": {
    "authKey": "AUTH_KEY_HERE"
  },
  "chatSDK": {
    "presenceSubscription": {
      "type": "ALL_USERS",
      "roles": []
    },
    "autoEstablishSocketConnection": true,
    "adminHost": null,
    "clientHost": null
  },
  "callsSDK": {
    "host": null,
    "adminHost": null,
    "clientHost": null,
    "callsHost": null
  },
  "uiKit": {
    "subscribePresenceForAllUsers": true
  }
}

Step 2 — init by importing the JSON. Metro bundles JSON imports natively (no extra config), so the file is read at build time exactly like the web kit:

// initFromSettings ships GA in @cometchat/chat-uikit-react-native >= 5.3.8 (ENG-35866)
import { CometChatUIKit } from "@cometchat/chat-uikit-react-native";
import cometchatSettings from "../cometchat-settings.json"; // adjust path to the file's location

await CometChatUIKit.initFromSettings(cometchatSettings);
// then: CometChatUIKit.login({ uid }) — see §2

• Commit cometchat-settings.json — do not gitignore it (the file is part of the integration). Its authKey is an optional demo/POC credential: a quick-start affordance so a PM or developer can see working chat before the backend auth-token flow is wired (that flow often waits on internal approvals). Because the file is committed to source control, treat the key as public — use a dedicated demo CometChat app (a committed key trips secret scanners and stays in git history; never reuse a production app's key). Switch to a server-minted authToken via loginWithAuthToken before production, where authKey must not ship.
• The init-once flag + "init before first render" rules below apply unchanged — just swap the init({...}) call for initFromSettings(cometchatSettings).

UIKitSettings — the init object (fallback — UI Kit before file-based init)

The v5 RN UI Kit's init() takes a flat UIKitSettings object (NOT a UIKitSettingsBuilder like the web kit). Pass fields directly:

import { CometChatUIKit } from "@cometchat/chat-uikit-react-native";

await CometChatUIKit.init({
  appId: APP_ID,                  // Required — from the CometChat dashboard
  region: REGION,                 // Required — "us" | "eu" | "in"
  authKey: AUTH_KEY,              // Required for dev mode. Omit in production.
  subscriptionType: "ALL_USERS",  // Optional — "NONE" | "ALL_USERS" | "ROLES" | "FRIENDS"
});

⚠️ UIKitSettingsBuilder does NOT exist in the v5 React Native UI Kit. That's a web-kit pattern. RN expects the flat object. If an agent imports UIKitSettingsBuilder from @cometchat/chat-uikit-react-native, the import resolves to undefined and new UIKitSettingsBuilder() throws at runtime.

Other valid UIKitSettings fields (all optional): autoEstablishSocketConnection, overrideAdminHost, overrideClientHost, disableCalling, extensions, roles, callingExtension. The full type is exported from the package as UIKitSettings; check the installed kit's type defs (node_modules/@cometchat/chat-uikit-react-native) if you need the exact shape.

Init must happen once

Use a module-level flag to prevent double-init. React re-mounts in dev (strict mode, fast refresh, and navigation nesting all trigger effect re-fires):

let initialized = false;

async function initCometChat(): Promise<void> {
  if (initialized) return;
  initialized = true;

  // Fail loud if env vars didn't load (EXPO_PUBLIC_* not set, or a config
  // module returning undefined). Empty creds otherwise surface later as a
  // cryptic init/login failure that's hard to trace. (audit P0-5)
  if (!APP_ID || !REGION || !AUTH_KEY) {
    throw new Error(
      "CometChat credentials are empty — check your EXPO_PUBLIC_* env (or config module) " +
        "and restart Metro with --reset-cache after editing it.",
    );
  }

  await CometChatUIKit.init({
    appId: APP_ID,
    region: REGION,
    authKey: AUTH_KEY,
    subscriptionType: "ALL_USERS",
  });
}

Init must run before first render

Put the init call in a top-level useEffect (preferred — the provider pattern in section 6 does this) or in App.tsx before the initial navigator mounts. Avoid calling init() in a screen's effect — by the time the screen mounts, the app has already tried to render components that expect init to be done.

---

2. Login

Development mode

let user;
try {
  user = await CometChatUIKit.getLoggedInUser();
} catch (e: any) {
  if (e?.code !== "NOT_FOUND") throw e;   // no-session is the expected "first run" path
}
if (!user) {
  await CometChatUIKit.login({ uid: "cometchat-uid-1" });  // note: OBJECT form
}

⚠️ getLoggedInUser() THROWS code: "NOT_FOUND" when there's no session — it does NOT return null. An uncaught throw here is the #1 cause of "app stuck on splash screen" — the provider's setReady(true) never fires. Always wrap in try/catch and treat NOT_FOUND as the normal first-run path. (Validated on @cometchat/chat-uikit-react-native@5.3.5, kit source CometChatUIKit.getLoggedInUser.)

⚠️ login() takes an object { uid: "..." } on React Native, not a bare string like on the web. Passing "cometchat-uid-1" directly silently fails.

Every new CometChat app ships 5 pre-seeded test users — cometchat-uid-1 through cometchat-uid-5. Use one for development.

⚠️ login() is safe sequentially, NOT concurrently

A second login() call fired while the first is in-flight throws "Please wait until the previous login request ends." Classic trap in React Native because:

• React strict mode double-mounts effects
• react-navigation remounts screens on tab switches
• Fast Refresh triggers effect re-runs in dev

Guard with a module-level in-flight promise, same pattern as the web skill:

let loginInFlight: Promise<unknown> | null = null;

async function ensureLoggedIn(uid: string, authToken?: string): Promise<void> {
  let existing;
  try {
    existing = await CometChatUIKit.getLoggedInUser();
  } catch (e: any) {
    if (e?.code !== "NOT_FOUND") throw e;   // first-run path
  }
  if (existing) return;
  if (loginInFlight) {
    await loginInFlight;   // reuse the pending promise
    return;
  }
  loginInFlight = authToken
    ? CometChatUIKit.login({ authToken })
    : CometChatUIKit.login({ uid });
  try {
    await loginInFlight;
  } finally {
    loginInFlight = null;
  }
}

Call ensureLoggedIn() from the provider / effect. Both mounts resolve against the same promise; only one login request hits the server.

Production mode

Use CometChatUIKit.login({ authToken }) with a token from your backend. The backend generates the token with the CometChat REST API using the server-only REST API Key (not the client-side Auth Key). See cometchat-native-production for the server-side token endpoint patterns.

Logout

await CometChatUIKit.logout();

Clears the local CometChat session. Call from your app's sign-out handler.

---

3. Provider wrapper chain (mandatory order)

Every CometChat RN app has this wrapper chain at the root. Missing wrappers cause silent layout breakage, broken gestures, or hard crashes — each wrapper is required by a specific RN ecosystem piece the UI Kit depends on.

// App.tsx (bare) or the root of your Expo app
import "react-native-gesture-handler";   // MUST be the first import
import { GestureHandlerRootView } from "react-native-gesture-handler";
import { SafeAreaProvider } from "react-native-safe-area-context";
import { CometChatThemeProvider } from "@cometchat/chat-uikit-react-native";

export default function App() {
  return (
    <GestureHandlerRootView style={{ flex: 1 }}>
      <SafeAreaProvider>
        <CometChatThemeProvider>
          <CometChatProvider>    {/* your own init/login provider — see section 6 */}
            <AppNavigator />
          </CometChatProvider>
        </CometChatThemeProvider>
      </SafeAreaProvider>
    </GestureHandlerRootView>
  );
}

Why each wrapper is mandatory:

Wrapper	Required because
import "react-native-gesture-handler" (at the very top of entry)	RNGH patches the global gesture system; must happen before any screen renders.
<GestureHandlerRootView style={{ flex: 1 }}>	Message composer swipe actions, attachment sheet drags, modal swipe-to-dismiss all use RNGH. No wrapper → gestures silently disabled.
<SafeAreaProvider>	UI Kit headers + bottom-sheets respect safe-area insets. Missing → content overlaps status bar / home indicator.
<CometChatThemeProvider>	Provides the JS theme context. UI Kit components read colors / fonts / styles from here. Missing → components throw or render with fallback styles that may look broken.
Your own <CometChatProvider>	Wraps the init + login lifecycle in React state so child components can gate on isReady. Not optional — you can't render UI Kit components before init + login complete.

The cometchat-native-expo-patterns and cometchat-native-bare-patterns skills show framework-specific nuances (Expo adds expo-splash-screen, bare adds pod setup), but the four-wrapper chain is fixed.

Recommended: include <CometChatI18nProvider> as a fifth wrapper. The kit's own SampleApp + SampleAppExpo always wrap <CometChatI18nProvider> between SafeAreaProvider and CometChatThemeProvider — even when the app is English-only. It's a no-op for default-locale apps and the wiring is identical to the other wrappers, so add it by default. The four-wrapper minimum is the strict floor; the five-wrapper shape is what every shipped sample uses. See cometchat-native-theming § 9 for the full chain (gesture → safe-area → i18n → theme → provider) and localization config.

---

4. Environment variables

Values to set

Variable	Purpose	Client-exposed?
APP_ID	Dashboard App ID	Yes
REGION	us | eu | in	Yes
AUTH_KEY	Dev-mode login key — never in production	Yes (dev only)
REST_API_KEY	Server-side token generation — server-only	NO — server env only

Where they live

• Bare RN: .env at project root + a runtime reader like react-native-config or babel-plugin-dotenv-import. Access: Config.APP_ID.
• Expo managed: app.json extra section + read via Constants.expoConfig?.extra?.APP_ID from expo-constants. Or use .env with expo-dotenv / expo-router's built-in support depending on SDK version. The cometchat-native-expo-patterns skill covers this in detail.

Do NOT bundle the REST_API_KEY into the client — RN bundles everything visible. Server endpoints live outside the RN app (Express / Hono / Cloud Functions); see cometchat-native-production.

.env / extra example

# client-side (safe to ship in the RN bundle for dev mode)
APP_ID=your_app_id
REGION=us
AUTH_KEY=your_auth_key

# server-only (NEVER ship — used by your token endpoint)
# REST_API_KEY=your_rest_api_key

---

5. Android + iOS platform notes

The UI Kit is cross-platform, but a few concerns only apply to one target:

Platform	Concern	Fix
iOS (bare)	Missing pod install after npm install	cd ios && pod install after adding or updating any CometChat dep
iOS	Apple privacy manifest (PrivacyInfo.xcprivacy) required since Xcode 15+	See docs/apple-privacy-manifest-guide.mdx; copied into cometchat-native-bare-patterns
iOS	Microphone / camera / photo-library permissions in Info.plist for calls + media messages	NSCameraUsageDescription, NSMicrophoneUsageDescription, NSPhotoLibraryUsageDescription strings
Android	Internet + read-media permissions in AndroidManifest.xml	INTERNET, READ_MEDIA_IMAGES, READ_MEDIA_VIDEO, RECORD_AUDIO (only what you need)
Both	Push notifications require the APNs + FCM dance — not automatic	Covered by SampleAppWithPushNotifications + cometchat-native-troubleshooting

The framework skills (cometchat-native-expo-patterns, cometchat-native-bare-patterns) apply these platform settings with the right syntax for each workflow.

---

6. Provider pattern

Instead of inlining init + login in every component, create a reusable CometChatProvider that gates rendering on isReady. Drop it below <CometChatThemeProvider> in the wrapper chain.

// CometChatProvider.tsx
import React, { createContext, useContext, useEffect, useState, type ReactNode } from "react";
import { CometChatUIKit } from "@cometchat/chat-uikit-react-native";

interface CometChatContextValue {
  isReady: boolean;
  error: string | null;
}

const CometChatContext = createContext<CometChatContextValue>({
  isReady: false,
  error: null,
});

export const useCometChat = () => useContext(CometChatContext);

// Module-level state — shared across all mounts
let initialized = false;
let loginInFlight: Promise<unknown> | null = null;

async function ensureLoggedIn(uid: string, authToken?: string): Promise<void> {
  let existing;
  try {
    existing = await CometChatUIKit.getLoggedInUser();
  } catch (e: any) {
    if (e?.code !== "NOT_FOUND") throw e;   // first-run path
  }
  if (existing) return;
  if (loginInFlight) {
    await loginInFlight;
    return;
  }
  loginInFlight = authToken
    ? CometChatUIKit.login({ authToken })
    : CometChatUIKit.login({ uid });
  try {
    await loginInFlight;
  } finally {
    loginInFlight = null;
  }
}

interface CometChatProviderProps {
  appId: string;
  region: string;
  authKey?: string;
  authToken?: string;
  uid?: string;
  children: ReactNode;
}

export function CometChatProvider({
  appId,
  region,
  authKey,
  authToken,
  uid = "cometchat-uid-1",
  children,
}: CometChatProviderProps) {
  const [isReady, setIsReady] = useState(false);
  const [error, setError] = useState<string | null>(null);

  useEffect(() => {
    async function setup() {
      try {
        if (!initialized) {
          initialized = true;
          await CometChatUIKit.init({
            appId,
            region,
            authKey,
            subscriptionType: "ALL_USERS",
          });
        }
        await ensureLoggedIn(uid, authToken);
        setIsReady(true);
      } catch (e) {
        setError(String(e));
      }
    }
    setup();
  }, [appId, region, authKey, authToken, uid]);

  if (error) {
    return null;  // or your app's error boundary — don't render CometChat components
  }
  if (!isReady) {
    return null;  // or a splash / loading screen
  }

  return (
    <CometChatContext.Provider value={{ isReady, error }}>
      {children}
    </CometChatContext.Provider>
  );
}

Children of <CometChatProvider> can use useCometChat() to check isReady — useful if some UI wants to render before chat is ready.

---

7. Anti-patterns

1. Do NOT call CometChatUIKit.init() during render. Init is async with side effects; calling during render triggers infinite re-renders. Always inside useEffect or before createRoot equivalent.

2. Do NOT call login("uid") with a string. RN's login() expects an object: login({ uid: "..." }). Passing a string silently no-ops.

3. Do NOT skip the four-wrapper chain (GestureHandlerRootView → SafeAreaProvider → CometChatThemeProvider → your provider). Each wrapper is required.

4. Guard concurrent login() with a module-level in-flight promise. login() is only safe sequentially. Two calls racing (React strict mode, tab remount, Fast Refresh) throw "Please wait until the previous login request ends."

5. Do NOT hardcode AUTH_KEY in source files. Use env vars for dev. Use login({ authToken }) in production.

6. Do NOT render CometChat components before isReady. The provider's isReady: false branch should return null (or a splash), not try to render children.

7. Do NOT re-initialize on navigation. Init and login belong at app root, not per-screen. Re-init causes WebSocket churn and lost messages mid-switch.

8. Do NOT invent component names. Only use components exported from @cometchat/chat-uikit-react-native. See cometchat-native-components for the catalog.

9. Do NOT forget import "react-native-gesture-handler" at the top of the entry file (App.tsx or index.js). Without it, swipe gestures in the composer and bottom sheets silently disable.

10. Do NOT bundle the REST API key. It's server-only. Token generation happens on your backend; the RN client never sees it.

---

8. Docs MCP (recommended, not required)

The CometChat docs MCP gives runtime access to the most current RN UI Kit docs. Install:

claude mcp add --transport http cometchat-docs https://www.cometchat.com/docs/mcp

Use the MCP to verify prop signatures, callback names, theme token names, or error message meanings before writing any non-obvious code. Everything the skills describe here is grounded in the docs — the MCP is how you double-check during generation.

Not required to install. The skills ship with the current truth baked in. The MCP is the fallback for edge cases and for upstream changes between skill releases.

---

9. Package dependencies

Minimum peer deps to install before the UI Kit works:

npm install \
  @cometchat/chat-sdk-react-native \
  @cometchat/chat-uikit-react-native \
  react-native-gesture-handler \
  react-native-safe-area-context \
  @react-native-clipboard/clipboard \
  react-native-svg \
  react-native-video \
  react-native-localize \
  punycode

The kit's declared peer deps include @react-native-clipboard/clipboard, react-native-svg, react-native-video, and react-native-localize (it imports all four) — install them or the bundle fails at runtime. react-native-safe-area-context is also required (imported by several components) though not formally declared.

Why punycode — still REQUIRED on 5.3.7 (kit 5.3.7's markdown path needs it). The kit's CometChatAIAssistantMessageBubble pulls in react-native-markdown-display → markdown-it@^10 → linkify-it@^2, which does require('punycode'). React Native / Metro does not bundle Node core modules, so Metro can't resolve punycode unless you install the userland package → otherwise the bundle fails with Unable to resolve module punycode. (This is NOT version-gone-from-Node — it's RN not shipping Node core libs; affects any kit whose markdown/AI path is reachable, incl. 5.3.5 AND 5.3.7.) Verified 2026-06-14 on a real expo export: Expo SDK 56 + RN 0.85.3 + kit 5.3.7 FAILED on punycode until the userland package was installed, then bundled clean (5.5 MB Hermes). Keep punycode in the install list — it is load-bearing whenever any feature that renders markdown / the AI Assistant bubble is reachable.

Note: react-native-reanimated is NOT a peer dependency of the kit (verified against @cometchat/chat-uikit-react-native@5.x peerDependencies). Add it only if your own app uses it for other animations.

Expo adds expo-av / expo-image-picker depending on which features you enable. Calls require the separate package PLUS the WebRTC native peers AND the polyfill peers the calls-sdk imports but doesn't declare:

npm install @cometchat/calls-sdk-react-native@^5 \
  @react-native-community/netinfo \
  react-native-callstats \
  react-native-webrtc \
  react-native-background-timer \
  react-native-url-polyfill \
  react-native-performance \
  valibot

@react-native-community/netinfo, react-native-callstats, and react-native-webrtc are the WebRTC native peers; react-native-background-timer, react-native-url-polyfill/auto, and react-native-performance are imported at the top of the calls-sdk dist/polyfills/browser.js, and valibot is consumed deeper in the calls state machine. The polyfill peers + valibot are NOT in the calls-sdk peerDependencies array — they fail at bundle resolution if missing. (Validated 2026-05-26 on @cometchat/calls-sdk-react-native@5.0.0.) Then run npx expo prebuild (Expo) or cd ios && pod install (bare) so the native modules get autolinked into the next debug build. This mirrors the lists in cometchat-native-features / cometchat-native-expo-patterns / cometchat-native-bare-patterns — see cometchat-native-calls for full calls setup.

See cometchat-native-features for when to add the calls SDK.

---

Skill routing reference

Skill	When to load
cometchat-native-core	Always — before any integration code
cometchat-native-components	Always — before writing any <CometChat*> JSX
cometchat-native-placement	When integrating — for placement patterns
cometchat-native-expo-patterns	Framework = Expo managed
cometchat-native-bare-patterns	Framework = bare React Native
cometchat-native-theming	When customizing themes
cometchat-native-features	When adding features (calls / extensions / AI)
cometchat-native-customization	When customizing components (text formatters, events, DataSource)
cometchat-native-production	When setting up server-side auth + user management
cometchat-native-troubleshooting	When diagnosing build errors, runtime failures, permission issues

Visual Builder integration

When the dispatcher's Step 3.1 sets customize=visual and the framework maps to builder platform react-native, skills runs cometchat builder export --platform react-native — a single CLI command that downloads the canonical static template ZIP from preview.cometchat.com/downloads/cometchat-builder-react-native.zip, fetches the per-builder settings JSON via GET /vcb/builders/{id}, applies F3 + F10 missing-field defaults, and writes the result to --output (default: src/config/).