When I freelanced, a long time ago, I used Solo[0] as a self-hosted solution. It allows only for one account manager but it was perfect for me.<p>It is written in PHP and the licence gave me permission to edit it the way I needed, so I did.<p>The same company also makes a &quot;full-featured&quot; alternative called Duet[1] that costs 49$ to buy.<p>[0]: <a href="http:&#x2F;&#x2F;www.getsoloapp.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.getsoloapp.com&#x2F;</a><p>[1]: <a href="https:&#x2F;&#x2F;duetapp.com" rel="nofollow">https:&#x2F;&#x2F;duetapp.com</a>