title: MailChimp merge_vars what else is accepted apart from FNAME & LNAME?
body: <p>I have implemented a very basic sign up using email address+name, although I would now like to add extra data such as Phone Number, Website etc. </p>
  
  <p>My question is where in the <a href="http://apidocs.mailchimp.com/api/1.3/" rel="noreferrer">API doc</a> can I find what else is supported apart from FNAME AND LNAME?</p>
  
  <p>At the moment I have:</p>
  
  <pre><code>$merge_vars = array(
       'FNAME' =&gt; $fname,
       'LNAME' =&gt; $lname
  );
  </code></pre>
  
  <p>I am using the method <code>listSubscribe</code> and this is the information that is provided above:</p>
  
  <pre><code>@param array $merge_vars optional merges for the email (FNAME, LNAME, etc.) (see examples below for handling "blank" arrays). Note that a merge field can only hold up to 255 bytes. Also, there are a few "special" keys:
                          string EMAIL set this to change the email address. This is only respected on calls using update_existing or when passed to listUpdateMember()
                          array GROUPINGS Set Interest Groups by Grouping. Each element in this array should be an array containing the "groups" parameter which contains a comma delimited list of Interest Groups to add. Commas in Interest Group names should be escaped with a backslash. ie, "," =&amp;gt; "\," and either an "id" or "name" parameter to specify the Grouping - get from listInterestGroupings()
                          string OPTINIP Set the Opt-in IP fields. &lt;em&gt;Abusing this may cause your account to be suspended.&lt;/em&gt; We do validate this and it must not be a private IP address.
                          array MC_LOCATION Set the members geographic location. By default if this merge field exists, we'll update using the optin_ip if it exists. If the array contains LATITUDE and LONGITUDE keys, they will be used. NOTE - this will slow down each subscribe call a bit, especially for lat/lng pairs in sparsely populated areas. Currently our automated background processes can and will overwrite this based on opens and clicks.
  
                          &lt;strong&gt;Handling Field Data Types&lt;/strong&gt; - most fields you can just pass a string and all is well. For some, though, that is not the case...
                          Field values should be formatted as follows:
                          string address For the string version of an Address, the fields should be delimited by &lt;strong&gt;2&lt;/strong&gt; spaces. Address 2 can be skipped. The Country should be a 2 character ISO-3166-1 code and will default to your default country if not set
                          array address For the array version of an Address, the requirements for Address 2 and Country are the same as with the string version. Then simply pass us an array with the keys &lt;strong&gt;addr1&lt;/strong&gt;, &lt;strong&gt;addr2&lt;/strong&gt;, &lt;strong&gt;city&lt;/strong&gt;, &lt;strong&gt;state&lt;/strong&gt;, &lt;strong&gt;zip&lt;/strong&gt;, &lt;strong&gt;country&lt;/strong&gt; and appropriate values for each
  
                          string date use YYYY-MM-DD to be safe. Generally, though, anything strtotime() understands we'll understand - &lt;a href="http://us2.php.net/strtotime" target="_blank"&gt;http://us2.php.net/strtotime&lt;/a&gt;
                          string dropdown can be a normal string - we &lt;em&gt;will&lt;/em&gt; validate that the value is a valid option
                          string image must be a valid, existing url. we &lt;em&gt;will&lt;/em&gt; check its existence
                          string multi_choice can be a normal string - we &lt;em&gt;will&lt;/em&gt; validate that the value is a valid option
                          double number pass in a valid number - anything else will turn in to zero (0). Note, this will be rounded to 2 decimal places
                          string phone If your account has the US Phone numbers option set, this &lt;em&gt;must&lt;/em&gt; be in the form of NPA-NXX-LINE (404-555-1212). If not, we assume an International number and will simply set the field with what ever number is passed in.
                          string website This is a standard string, but we &lt;em&gt;will&lt;/em&gt; verify that it looks like a valid URL
  </code></pre>