intellectual-property software
Is it legal to develop and sell software that operates in a similar fashion to available software?
<p>I'm currently working on a project that can provide remote desktop assistance like <a href="https://www.realvnc.com/" rel="nofollow noreferrer">RealVNC</a>. There are many programs already available providing similar services <a href="https://en.wikipedia.org/wiki/Comparison_of_remote_desktop_software" rel="nofollow noreferrer">(like these programs)</a>.  I wrote all code myself.</p>

<p>Can I sell my program or it's not legal because there are already programs providing same features?</p>

<p>It's legal to sell your program if it doesn't infringe any law or anyone else's intellectual property.  Examples of things that can get you into trouble:</p>

<ol>
<li><p><a href="/questions/tagged/statutes" class="post-tag" title="show questions tagged &#39;statutes&#39;" rel="tag">statutes</a>: Some countries have export laws that forbid you to distribute certain types of encryption without proper export controls.</p></li>
<li><p><a href="/questions/tagged/patents" class="post-tag" title="show questions tagged &#39;patents&#39;" rel="tag">patents</a>: If you use a design or invention that is under patent protection you could be liable for infringing patent rights.</p></li>
<li><p><a href="/questions/tagged/trademark" class="post-tag" title="show questions tagged &#39;trademark&#39;" rel="tag">trademark</a>: If you improperly use a trademarked name you could be subject to damages.</p></li>
<li><p><a href="/questions/tagged/licensing" class="post-tag" title="show questions tagged &#39;licensing&#39;" rel="tag">licensing</a>: If you violate a license to which you have agreed you can be sued for damages.</p></li>
<li><p><a href="/questions/tagged/copyright" class="post-tag" title="show questions tagged &#39;copyright&#39;" rel="tag">copyright</a>: If you appear to have copied something without license you can be liable for damages.</p></li>
<li><p>Just because: <a href="https://law.meta.stackexchange.com/q/224/10">If someone wants to sue you, they can</a>.</p></li>
</ol>

<p>Since there's no way to guarantee your business won't run into liability from infringement &ndash; or from some other failure &ndash; people normally conduct <a href="/questions/tagged/business" class="post-tag" title="show questions tagged &#39;business&#39;" rel="tag">business</a> through entities like LLCs that shield them from personal liability.  Depending on their concerns and finances, they may also:</p>

<ul>
<li><p>Buy liability <a href="/questions/tagged/insurance" class="post-tag" title="show questions tagged &#39;insurance&#39;" rel="tag">insurance</a></p></li>
<li><p>Consult professionals like IP lawyers to:</p>

<ol>
<li><p>review their business and products in advance to look for and address glaring infringements, and/or</p></li>
<li><p>correctly protect their IP using the tools mentioned above.</p></li>
</ol></li>
</ul>

<p>In principle it's legal to sell software that acts like VNC.  </p>

<p>Better then that: <a href="https://en.wikipedia.org/wiki/RFB_protocol#History" rel="nofollow noreferrer">Older versions of the VNC protocol (RFB) are open source</a>, and the protocol details are well documented, which would make it hard for anyone to say "your remote viewing software is infringing on our IP."</p>
