# MerchantProcessorMode

A model the API reference uses in a request or a response. The operation pages link every field typed as this model here.

How a `Sandbox` merchant's transactions pick a processor: against
the synthetic loopback processor, or against a real processor's test host.

## Values

| Value | Description |
| --- | --- |
| `Loopback` | Route to the merchant's loopback processor profile. The loopback contributor is synthetic and performs no external I/O, so a sandbox merchant in this mode can be exercised end to end without any processor credentials. |
| `ProcessorTest` | Route to a real processor profile, which the merchant's sandbox environment already pins to that processor's test host. |

## See also

- [All documentation](https://devportal.demo.winkpg.io/llms.txt): the machine-readable index of every public page on this site.