I am building a project requiring high performance and scalability, entailing:

<ul><li><a href="http://en.wikipedia.org/wiki/Role-based_access_control" rel="nofollow">Role-based authentication</a> with <a href="http://en.wikipedia.org/wiki/Application_programming_interface_key" rel="nofollow">API-key</a> licensing to access data of specific users</li>
<li><a href="http://en.wikipedia.org/wiki/Application_programming_interface" rel="nofollow">API</a> exposed with <a href="http://en.wikipedia.org/wiki/REST" rel="nofollow">REST</a> (<a href="http://en.wikipedia.org/wiki/XML" rel="nofollow">XML</a>, <a href="http://en.wikipedia.org/wiki/JSON" rel="nofollow">JSON</a>), <a href="http://en.wikipedia.org/wiki/XMLRPC" rel="nofollow">XMLRPC</a>, <a href="http://en.wikipedia.org/wiki/JSONRPC" rel="nofollow">JSONRPC</a> and <a href="http://en.wikipedia.org/wiki/SOAP" rel="nofollow">SOAP</a></li>
<li>"Easily" configurable <a href="http://en.wikipedia.org/wiki/Mutator_method" rel="nofollow">getters and setters</a> to create APIs accessing the same data but with input/output in different <a href="http://en.wikipedia.org/wiki/Database_schema" rel="nofollow">schemas</a></li>
</ul>

<p>A conservative estimate of the number of tables—often whose queries require joins—is: 20.</p>

<p>Which database type—e.g.: <a href="http://en.wikipedia.org/wiki/NoSQL" rel="nofollow">NoSQL</a> or <a href="http://en.wikipedia.org/wiki/Database_management_system" rel="nofollow">DBMS</a>—<a href="http://en.wikipedia.org/wiki/Key-value_data_store" rel="nofollow">key-value data store</a> or <a href="http://en.wikipedia.org/wiki/Object-relational_database" rel="nofollow">object-relational database</a>—e.g.: <a href="http://en.wikipedia.org/wiki/Redis" rel="nofollow">Redis</a> or <a href="http://en.wikipedia.org/wiki/PostgreSQL" rel="nofollow">PostgreSQL</a>—and <a href="http://en.wikipedia.org/wiki/Web_application_framework" rel="nofollow">web-framework</a>—e.g. <a href="http://en.wikipedia.org/wiki/Django_%28web_framework%29" rel="nofollow">Django</a>, <a href="http://www.web2py.com/" rel="nofollow">Web2Py</a> or <a href="http://flask.pocoo.org/" rel="nofollow">Flask</a>—would you recommend?</p>