# Swap API `OBRouter` is the primary contract which is interacted with in day-to-day use, including those that engage through calldata retrieved from the Swap API. `pathDefinition` is generated by the API. This is fed into`OBExecutor` to carry out the swap route. This value should never be tampered as it can cause to loss of funds. `OBExecutor` is ephemeral and may change often (to include new liquidity sources). Therefore, it should never be hardcoded. It should always be returned from the Swap API. It is also not recommended to call `OBExecutor` directly. {% hint style="info" %} API responses are limited to 1000 requests per minute. If you require a higher rate limit, please ping us on telegram @beranoulli or @whoiskevinn. {% endhint %}