Since Elon Musk took over Twitter, the company that owns the social network of the same name has gone through significant job cuts. According to internal documents seen by CNBC, the layoffs reduced Twitter's headcount by 80% and now has just 1,300 active employees, including fewer than 550 full-time engineers.

About 75 employees are on vacation, including about 40 engineers. Also, the company's staff includes about 1,300 non-working employees who have kept their pay, but they will no longer be involved in their previous positions in the social network. Many of them resigned when Elon Musk sent out a letter calling on the company's employees to work hard "long hours" to create a breakthrough Twitter 2.0. In addition, Musk recruited about 130 people from his companies, including Tesla, SpaceX and The Boring Company, as well as employees from venture capital funds and other firms, to work on Twitter.

Despite the fact that Musk promised to do without significant cuts, most of the staff - about 80% - were fired or forced to leave due to disagreement with the policy of the new leadership, including in relation to remote work on a permanent basis, which was introduced under former CEO Jack Dorsey.

Prior to Musk's ownership of Twitter, the company had about 7,500 employees. Even before that, there were rumors about the upcoming staff reduction, which was supposed to happen regardless of whether the deal for its purchase by Musk goes through or not. However, Musk cut Twitter's headcount far more than many expected. And now, according to a former employee of the company, this may affect the quality of service of the service against the backdrop of adding new features.

According to him, the code base of the service is huge and requires knowledge of various platforms and programming languages to support its different areas - for example, advertising services. The CNBC interviewee says it will be difficult to train engineers on how to use the service after losing so much institutional knowledge.