> ## Documentation Index
> Fetch the complete documentation index at: https://docs.go.gbgplc.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Official SDKs for integrating GBG GO into your applications

GBG GO provides a set of SDKs that simplify integration. Each SDK serves a distinct role depending on where your code runs and what you're building.

## SDK architecture

The diagram below shows where each SDK runs and how they hand off the journey URL and bridge messages between your server, the GBG GO platform, and the end-user device:

```mermaid theme={null}
graph LR
    subgraph Server["Your server"]
        A["Core SDK<br/>@gbg/go-core"]
    end
    subgraph GBG["GBG GO"]
        API["GBG GO API"]
        B["Web journey"]
    end
    subgraph Device["End user device"]
        D["iOS Bridge SDK"]
        E["Android Bridge SDK<br/>(Coming soon)"]
        F["Web Embed SDK<br/>(Coming soon)"]
    end
    A -->|"Start journey"| API
    API -->|"Return journey URL"| A
    A -->|"Pass journey URL"| D
    A -.->|"Pass journey URL"| E
    A -.->|"Pass journey URL"| F
    API <-->|"Journey data"| B
    D <-->|"Bridge messaging"| B
    E -.->|"Bridge messaging"| B
    F -.->|"Bridge messaging"| B
    style E fill:#f5f5f5,stroke:#ccc,color:#999
    style F fill:#f5f5f5,stroke:#ccc,color:#999
```

| SDK                                                                      | Purpose                                                                                      | Runs on                          |
| ------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------- | -------------------------------- |
| [Core SDK](/docs/go-v2/developer-integration/sdks/core-sdk)              | Type-safe client for the GBG GO API. Generate tokens, start journeys, manage tasks.          | Your server (Node.js, Bun, Deno) |
| [iOS Bridge SDK](/docs/go-v2/developer-integration/sdks/ios-sdk)         | Native iOS host that loads the web journey in a `WKWebView` and fulfils capability requests. | Your iOS app                     |
| [Android Bridge SDK](/docs/go-v2/developer-integration/sdks/android-sdk) | Native Android host that loads the web journey and fulfils capability requests.              | Your Android app                 |

## Which SDK do I need?

* **Server-side integration only**: use the Core SDK to authenticate, start journeys, submit data, and check results from your backend. This is sufficient if you're building a server-driven flow or using the API directly.
* **Embed a journey in a web app or iframe**: use the Core SDK on your server to generate tokens and journey URLs. The hosted web journey handles device capabilities automatically when embedded in a browser.
* **Embed a journey in a native iOS app**: use the Core SDK on your server to generate tokens and journey URLs, and the iOS Bridge SDK to load the web journey in a `WKWebView` and fulfil capability requests like camera capture, NFC, and biometrics.
* **Embed a journey in a native Android app**: same pattern as iOS — use the Core SDK server-side and the Android Bridge SDK as the native host. *(Coming soon)*

## Typical integration flow

1. **Your server** uses the Core SDK to authenticate and generate a journey URL with an end-user token.
2. **Your app** loads that URL in a WebView (iOS/Android) or iframe (web).
3. **The web journey** runs inside the WebView/iframe and automatically detects the host environment.
4. **The native host** (iOS or Android Bridge SDK) receives capability requests and fulfils them using device hardware.

<Note>
  The Bridge SDKs handle all messaging between the web journey and the native host automatically. You only need to implement handlers for the capabilities your app supports (e.g., document camera, selfie camera, NFC).
</Note>