user41906: With the importaddress RPC command it is possible to import one watch-only address.
But how can I do that with, let's say, 100?

user5757: The RPC interface doesn't generally provide any "batch mode" functionality.  If you want to import 100 addresses, call importaddress 100 times.  You might like to write a short script with a loop in some other language.
You should set the rescan parameter to false for all but the last address, so that you don't trigger rescanning 100 times.

user2075: There is an alternate command importmulti to be used as follows:
bitcoin-cli importmulti '[
{
  "scriptPubKey" : { "address": "mxbvcPj7cnbxPP6oqpHJxxNb4xC8QoLquG" },
  "timestamp" : 0,
  "label" : "mxbvcPj7cnbxPP6oqpHJxxNb4xC8QoLquG"
},
{
  "scriptPubKey" : { "address": "n1iNb8XafoJTrCBBcGSSEZ6YNd6EWYo8PU" },
  "timestamp" : 0,
  "label" : "n1iNb8XafoJTrCBBcGSSEZ6YNd6EWYo8PU"
},
{
  "scriptPubKey" : { "address": "mgLs7quWwYBJa7jkZyebAec7RNXQtwaerK" },
  "timestamp" : 0,
  "label" : "mgLs7quWwYBJa7jkZyebAec7RNXQtwaerK"
}]' '{"rescan":false}'

Response is as follows:
[
  {
    "success": true
  }, 
  {
    "success": true
  }, 
  {
    "success": true
  }
]


41906: <p>With the <a href="https://bitcoin.org/en/developer-reference#importaddress" rel="noreferrer">importaddress</a> RPC command it is possible to import one watch-only address.
But how can I do that with, let's say, 100?</p>
 5757: <p>The RPC interface doesn't generally provide any "batch mode" functionality.  If you want to import 100 addresses, call <code>importaddress</code> 100 times.  You might like to write a short script with a loop in some other language.</p>

<p>You should set the rescan parameter to <code>false</code> for all but the last address, so that you don't trigger rescanning 100 times.</p>
 2075: <p>There is an alternate command <code>importmulti</code> to be used as follows:</p>

<pre><code>bitcoin-cli importmulti '[
{
  "scriptPubKey" : { "address": "mxbvcPj7cnbxPP6oqpHJxxNb4xC8QoLquG" },
  "timestamp" : 0,
  "label" : "mxbvcPj7cnbxPP6oqpHJxxNb4xC8QoLquG"
},
{
  "scriptPubKey" : { "address": "n1iNb8XafoJTrCBBcGSSEZ6YNd6EWYo8PU" },
  "timestamp" : 0,
  "label" : "n1iNb8XafoJTrCBBcGSSEZ6YNd6EWYo8PU"
},
{
  "scriptPubKey" : { "address": "mgLs7quWwYBJa7jkZyebAec7RNXQtwaerK" },
  "timestamp" : 0,
  "label" : "mgLs7quWwYBJa7jkZyebAec7RNXQtwaerK"
}]' '{"rescan":false}'
</code></pre>

<p>Response is as follows:</p>

<pre><code>[
  {
    "success": true
  }, 
  {
    "success": true
  }, 
  {
    "success": true
  }
]
</code></pre>
