The and predicate matches if all of its sub-predicates match.

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

{
  "port": 4554,
  "protocol": "tcp",
  "mode": "text",
  "stubs": [
    {
      "responses": [{ "is": { "data": "matches" } }],
      "predicates": [
        {
          "and": [
            { "startsWith": { "data": "start" } },
            { "endsWith": { "data": "end\n" } },
            { "contains": { "data": "middle" } }
          ]
        }
      ]
    }
  ]
}

The first request matches all sub-predicates, triggering the stub response:

echo 'start middle end' | nc localhost 4554

matches

The stub matches two of the three sub-predicates, which is not enough to match the and predicate.

The stub does not match none of the sub-predicates match...

echo 'start end' | nc localhost 4554

No response is sent.