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

# Transit API Integration

> Perform cross-chain stablecoin transfers using our REST API.

The Transit API returns ready-to-sign transaction calldata for cross-chain stablecoin transfers. The server handles quote generation, fee calculation, and ABI encoding — you get back a transaction object to sign and broadcast.

All Transit endpoints are public and do not require authentication.

## When to Use Transit

* **Cross-chain stablecoin movement** — Transfer USDC, USDT, PYUSD, or USDG between supported chains
* **Backend transaction builders** — Fetch calldata via API, sign and submit from any language
* **Custodial wallets** — Get transaction data server-side, route to your signing infrastructure

## Prerequisites

* An EVM wallet with sufficient balance for the offer amount plus native gas
* An HTTP client (`curl`, `fetch`, `requests`, etc.)

## Endpoints

| Endpoint                          | Purpose                                                  |
| --------------------------------- | -------------------------------------------------------- |
| `GET /v1/transit/routes`          | Discover available asset pairs and minimum order sizes   |
| `GET /v3/core/authorization`      | Check token approval status and get permit/approval data |
| `GET /v1/transit/orders/quote`    | Build order submission calldata                          |
| `GET /v1/transit/orders/:orderId` | Get order status and execution details                   |
| `GET /v1/transit/orders`          | List orders for a user address                           |

## Integration Flow

<Steps>
  <Step title="Discover Routes">
    Query available asset pairs to find a route matching your source and destination chains.
  </Step>

  <Step title="Check Authorization">
    Call `/v3/core/authorization` to detect whether the offer token requires a permit signature, an approval transaction, or is already approved for the TransitStation contract.
  </Step>

  <Step title="Get Order Quote">
    Fetch signed calldata for the `submitOrder` transaction, including the messaging fee. If using permits, pass the signature and deadline.
  </Step>

  <Step title="Submit Transaction">
    Broadcast the transaction on the source chain with the returned `to`, `data`, and `value`.
  </Step>

  <Step title="Track Order">
    Poll the order status endpoint until fulfillment completes on the destination chain.
  </Step>
</Steps>

## Supported Chains

| Chain    | ID   |
| -------- | ---- |
| Ethereum | 1    |
| RH Chain | 4663 |

## Getting Started

<CardGroup cols={2}>
  <Card title="Route Discovery" icon="route" href="/v1.0.0/intro/products/transit/developers/guides/route-discovery">
    Find available asset pairs and check minimum order sizes.
  </Card>

  <Card title="Order Submission" icon="paper-plane" href="/v1.0.0/intro/products/transit/developers/guides/order-submission">
    Get quote calldata and submit cross-chain orders.
  </Card>

  <Card title="Order Tracking" icon="clock" href="/v1.0.0/intro/products/transit/developers/guides/order-tracking">
    Monitor order status and view execution history.
  </Card>

  <Card title="AI Coding Reference" icon="robot" href="/v1.0.0/intro/products/transit/developers/ai-reference">
    Condensed reference for AI coding assistants.
  </Card>
</CardGroup>