# 🔁 Swap Scenarios

There are 4 scenarios for Crosschain transactions.

#### 1️⃣ Bridge Only

* Example: **Bridge ETH on Base to ETH on Arbitrum**
* Only supported tokens (USDC, USDT, WETH, etc) can be bridged directly. These tokens vary by source and destination chain.

#### 2️⃣ Swap → Bridge

* Example: **Swap BNB on BNB Chain to USDC on Arbitrum**
* Swap BNB to a supported bridge token (e.g. USDC) using PancakeSwap pools on BNB chain
* Bridge USDC via Across to Arbitrum

#### 3️⃣ Bridge → Swap

* Example: **Swap USDC on BNB Chain to ARB on Arbitrum**
* Bridge USDC via Across
* Swap USDC to ARB using PancakeSwap pools on Arbitrum

#### 4️⃣ Swap → Bridge → Swap

* Example: **Swap BNB on BNB Chain to ARB on Arbitrum**
* Swap BNB to a bridge token (maximizing user output)
* Bridge via Across
* Swap bridged token to ARB on Arbitrum using PancakeSwap pools

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### ⚠️ Fail Cases

| Scenario                              | Outcome                                                                                                                                                                                         |
| ------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Swap/Tx Failure on Source Chain**   | User instantly receives the original token on source chain                                                                                                                                      |
| **Bridge Tx Failure**                 | Across processes a refund within 90 mins to 2 hours, and user receives the bridged asset on source chain. While Relay processes the refund within a minute in such scenario between SOL <> EVM. |
| **Swap Failure on Destination Chain** | User receives the bridged asset on the destination chain                                                                                                                                        |