> For the complete documentation index, see [llms.txt](https://docs.onyx.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.onyx.org/developer-guide/bridge.md).

# Bridge Integration

The Onyx bridge moves XCN, ETH, and USDC between Ethereum Mainnet and Onyx Mainnet.

| Interface                | URL                                          |
| ------------------------ | -------------------------------------------- |
| User interface           | `https://app.onyx.org/bridge`                |
| **REST API (preferred)** | **`https://bridgeapi.onyx.org/api/v1`**      |
| REST API (legacy alias)  | `https://bridge.goliath.net/api/v1`          |
| Ethereum BridgeLock      | `0xa9fd64b5095d626f5a3a67e6db7fb766345f8092` |
| Onyx BridgeMint          | `0x1d14ae13ca030eb5e9e2857e911af515cf5ffff2` |

{% hint style="info" %}
**External integrators** should call **`https://bridgeapi.onyx.org/api/v1`** directly. The first-party app may use a same-origin proxy under `app.onyx.org`; that path is optional for browser UIs and is **not** required for server-side or partner clients. `bridgeapi.onyx.org` and `bridge.goliath.net` dual-serve the same API with **no redirect** between hosts.
{% endhint %}

## Integration rules

* Call `GET /health` before enabling a bridge action.
* Fetch `GET /bridge/limits` and a fee quote immediately before presenting or submitting a transfer.
* Poll `GET /bridge/status` using the source transaction hash and surface the returned status truthfully.
* Treat maintenance or delayed states as unavailable/in-progress, not as success.
* For native XCN from Onyx to Ethereum, register the signed intent first and send only to the destination returned by that response.
* ERC-1271 signatures from deployed smart accounts are supported. For ERC-4337, bind the final execution transaction hash, not the user-operation hash.

Processing time depends on source-chain confirmation, relayer state, security holds, and destination submission. Applications must use API state instead of promising a fixed duration.

See the [REST API Reference](/developer-guide/bridge/api-reference.md), [Smart Account Integration](/developer-guide/bridge/smart-account-integration.md), and [contract registry](/reference/contracts.md).


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