# Coconut credential generation
The following code shows how you can use the SDK to create and use a credential representing paid bandwidth on the Sandbox testnet.

```rust,noplayground
{{#include ../../../../../../sdk/rust/nym-sdk/examples/bandwidth.rs}}
```

You can read more about Coconut credentials (also referred to as `zk-Nym`) [here](https://nymtech.net/docs/coconut.html).
