In recent years, ‘hidden overtime’ has gradually emerged as a new focal point in labour disputes. On 27 April 2024, the Beijing No. 2 Intermediate People’s Court issued a circular regarding the protection of employees’ rights to rest and leave. Data shows that over the past three years, the court has concluded a total of 4,177 labour dispute cases involving rest and leave, of which 619 were related to the ‘right to offline rest’, accounting for approximately 30 per cent of the total number of overtime pay cases during the same period. With the widespread use of instant messaging tools such as WeChat and DingTalk, it has become increasingly common for employees to be required to handle work-related matters via these platforms after finishing work. For example, employees may be tagged (@) in work discussions after finishing their shift, or be scheduled for online meetings and training outside working hours. This phenomenon is gradually blurring the boundaries between work and personal life, and has given rise to so-called ‘invisible overtime’. Such overtime typically occurs at home, involves fragmented periods of time that are difficult to define clearly, and often leads employees to claim overtime pay from their employers on the grounds that they handled work online during non-working hours. In judicial practice, disputes in such cases primarily centre on several key issues: how to establish the existence of overtime, who bears the burden of proof, the validity of electronic evidence, and how overtime pay should be calculated. As electronic evidence generated via instant messaging tools is easily replicated or tampered with, its authenticity and integrity are frequently called into question, presenting a challenge for the courts in their deliberations. A typical case provides a relatively clear reference for determining ‘hidden overtime’. Mr Wang joined an engineering firm as an engineer in July 2020, working under a standard working hours system. During his employment, the company frequently organised online meetings and training sessions via DingTalk or WeCom after working hours, stipulating that employees who did not attend would be required to make a ‘voluntary donation’ of 200 yuan. Mr Wang submitted evidence, including meeting minutes and screenshots of chat logs, demanding that the company pay him a total of over 85,000 yuan in overtime pay for extended working hours, rest days and statutory public holidays. The company argued that, according to the employment contract, overtime required prior application and approval; attending online meetings merely required logging into an account, and employees were not necessarily required to speak or listen attentively, so this could not prove that they had actually participated in work; furthermore, the “donation” requirement was unrelated to whether or not one attended the meetings. After deliberation, the court ruled that the evidence provided by Mr Wang demonstrated that the company had indeed arranged online meetings and training sessions outside normal working hours. As these activities were organised by the company, employees were obliged to attend, and the “donation” requirement further indicated that such arrangements were, to some extent, compulsory. These activities consumed the employee’s rest time and energy and should therefore be recognised as overtime. However, the court also noted that Wang had joined some meetings significantly later than their scheduled start times, whilst the company argued that attending a meeting typically required only logging in without actual participation. Simply calculating overtime hours based on the start and end times of the meetings would not be fair to the company. After taking all factors into account, the court ultimately ruled that the company should pay Wang a total of 19,000 yuan in overtime pay. In summarising the significance of this case, the court explicitly set out two key principles. Firstly, even if online activities do not require sustained physical or mental exertion, they should be deemed overtime if the employer arranges them during non-working hours—whether through direct or indirect means—and this clearly infringes upon the employee’s right to rest. Secondly, when calculating overtime hours, a reasonable assessment should be made based on the specific circumstances, rather than a simple, mechanical calculation based solely on the start and end times of the meetings. The court also reminded employees to be more vigilant about preserving evidence, ensuring they properly retain original documents such as employment contracts, payslips, attendance records, overtime approval forms, and communication records relating to overtime. For online overtime, particular attention should be paid to preserving electronic evidence such as meeting notifications, chat logs and work assignments. At the same time, the court has also issued recommendations to employers: they should foster a healthy and reasonable corporate culture, and organise working hours and remuneration structures in a scientific manner. Where overtime is genuinely necessary, employers should consult with the trade union or employees in accordance with the law, and provide compensatory time off or pay overtime wages as required by law. More importantly, employers must safeguard employees’ right to rest outside working hours, ensuring that staff can truly rest when they are offline and receive fair remuneration when they are working, thereby avoiding disputes arising from ‘hidden overtime’.