# Chat SDKs > Put Kustomer chat and the knowledge base in your website and mobile apps. Pick an SDK, compare what each platform supports, and see how identity, push and the server-side chat API fit together. Source: https://developer.kustomer.com/docs/chat Kustomer Chat connects customers in your website or app with agents and AI assistants in Kustomer. Conversations are real Kustomer conversations: they show up in the agent's queue, run through your workflows and routing, and follow the customer across devices once you identify them. Each SDK comes in two layers. The **UI** layer is a complete chat and knowledge base experience you can open with one call and style to your brand. The **core** layer is the headless API under it, for when you want to build your own interface. - [Web](https://developer.kustomer.com/docs/chat/web): One script tag for the chat widget, or the Core API for a custom UI in any framework. - [iOS](https://developer.kustomer.com/docs/chat/ios): The `KustomerChat` Swift module, through Swift Package Manager or CocoaPods. - [Android](https://developer.kustomer.com/docs/chat/android): `com.kustomer.chat:ui` and `:core` on Maven Central, written in Kotlin. - [React Native](https://developer.kustomer.com/docs/chat/react-native): `@kustomer/chat-react-native`, wrapping the native iOS and Android SDKs. Not building a customer-facing UI? To bring conversations from your own chat system or bot into Kustomer, use the [server-side chat API](https://developer.kustomer.com/docs/chat/server-chat-api). ## Latest versions | SDK | Package | Version | Minimum platform | | ------------ | ------------------------------------------------ | -------------- | ----------------------------------- | | Web widget | `https://cdn.kustomerapp.com/chat-web/widget.js` | Always current | — | | Web Core | `https://cdn.kustomerapp.com/chat-web/core.js` | Always current | — | | iOS | `kustomer-ios-spm` or `pod 'KustomerChat'` | 8.3.0 | iOS 15 | | Android | `com.kustomer.chat:ui` | 4.6.2 | API 24, Kotlin 2.2 toolchain | | React Native | `@kustomer/chat-react-native` | 6.3.6 | React Native 0.77, iOS 15.1, API 24 | ## What each platform supports | Capability | Web widget | Web Core | iOS | Android | React Native | | ----------------------------------------- | ---------------------------------- | -------- | --------------------- | ----------------- | ------------------------ | | Prebuilt chat and knowledge base UI | Yes | — | Yes | Yes | Yes (native UI) | | Headless API for your own UI | — | Yes | Yes | Yes | Create conversation only | | Open a specific conversation | Yes | — | Yes | Yes | Yes | | Start a conversation with a first message | Yes | Yes | Yes | Yes | Yes | | AI assistants | Yes | Yes | Yes | Yes | Yes | | Identify customers with a JWT | Yes | Yes | Yes | Yes | Yes | | Customer and conversation attributes | Yes | Yes | Yes | Yes | Yes | | Unread count | Yes | Yes | Yes | Yes | Yes | | Availability (business hours) | Yes | Yes | Yes | Yes | Yes | | Typing indicators in your own UI | — | Yes | Yes | Yes | — | | Knowledge base in your own UI | — | Yes | Yes | Yes | — | | Satisfaction surveys in your own UI | — | Yes | — | Yes | — | | Attachments | Yes | Yes | Yes | Yes | Yes (native UI) | | Import a conversation (handoff) | Yes | Yes | Yes | Yes | Yes | | Push notifications | — | — | APNs | FCM | APNs and FCM | | Theme colors | Kustomer settings | Your CSS | Asset catalog or code | Theme attributes | Native, per platform | | Override UI strings | Greeting and messages, in Kustomer | Your UI | `Kustomer.strings` | `kus_*` resources | Native, per platform | | Link previews | Yes | Yes | Yes | Yes | Yes | | History status filter | Yes | — | Yes | Yes | Yes | Where a capability says "your own UI", the prebuilt UI already handles it; the column shows whether the headless API exposes it for custom builds. ## How the pieces fit #### Configure chat in Kustomer Admins set chat's appearance, greeting, business hours, assistants and knowledge base per brand in **Apps › Chat**. The SDKs load these settings at startup, so most changes need no app release. #### Create a chat key Every SDK uses an API key with **only** the `org.tracking` role. It's meant to ship in your page or app, because that role only covers what a chat customer can do. Don't add other roles to it; the mobile SDKs reject keys that have them. #### Add the SDK and open chat Follow the quickstart for your platform. Out of the box, chat works for anonymous visitors. #### Identify signed-in customers Your server signs a short-lived JWT, and the SDK logs in with it, so conversations attach to the customer's profile and appear on all their devices. See [Customer identity](https://developer.kustomer.com/docs/chat/identity). #### Add push on mobile Upload your APNs key or Firebase service account in Kustomer and forward tokens from your app. See [Push notifications](https://developer.kustomer.com/docs/chat/push-notifications). For what happens between the SDK and Kustomer, with HTTPS requests for writes and a realtime channel for messages, typing and presence, see [How chat works](https://developer.kustomer.com/docs/chat/realtime-architecture). ## Choosing between UI and core | Use the prebuilt UI when | Use core when | | -------------------------------------------------------------------------------- | --------------------------------------------------------------------------- | | You want chat live quickly, with Kustomer's tested UX | Chat has to look and behave exactly like the rest of your product | | Admins should control branding and copy without releases | You're embedding chat inside an existing screen rather than a sheet | | You need the knowledge base, CSAT, attachments and assistants without extra work | You only need part of chat, such as unread counts or starting conversations | You can mix them: many apps use the prebuilt UI and only call core for unread counts or to start a conversation from a help button with context attached. > **For AI agents:** Every chat page is available as Markdown by appending `.md` to its URL, and [`/llms.txt`](https://developer.kustomer.com/llms.txt) indexes them. When generating integration code, use the versions and method signatures on these pages; older examples elsewhere often use deprecated calls such as `Kustomer.configure` on iOS or callback overloads that no longer exist on Android.