Let's create a binary-based imposter with multiple stubs:

POST /imposters HTTP/1.1
Host: localhost:<%= port %>
Accept: application/json
Content-Type: application/json

{
  "port": 4549,
  "protocol": "tcp",
  "mode": "binary",
  "stubs": [
    {
      "responses": [{ "is": { "data": "Zmlyc3QgcmVzcG9uc2U=" } }],
      "predicates": [{ "endsWith": { "data": "AwQ=" } }]
    },
    {
      "responses": [{ "is": { "data": "c2Vjb25kIHJlc3BvbnNl" } }],
      "predicates": [{ "endsWith": { "data": "BQY=" } }]
    },
    {
      "responses": [{ "is": { "data": "dGhpcmQgcmVzcG9uc2U=" } }],
      "predicates": [{ "endsWith": { "data": "BQY=" } }]
    }
  ]
}

We'll use the command line base64 tool to decode the request to binary before sending to the imposter. We're sending a base64-encoded version of four bytes: 0x1, 0x2, 0x3, and 0x4. Our first predicate is a base64 encoded version of 0x3 and 0x4. The response is a base64-encoded version of the string "first response":

echo 'AQIDBA==' | base64 --decode | nc localhost 4549

first response

Next we'll send 0x1, 0x2, 0x4, 0x5, and 0x6, matching on a predicate encoding 0x5 and 0x6:

echo 'AQIDBAUG' | base64 --decode | nc localhost 4549

second response

The third stub will never run, since it matches the same requests as the second stub. mountebank always chooses the first stub that matches based on the order you add them to the stubs array when creating the imposter.