EU employers may monitor Slack or Teams messages during investigations only in limited, justified circumstances. Routine or blanket monitoring is not permitted. The employer generally needs to show that the monitoring was necessary, proportionate, and targeted to a specific issue.
The core EU principle: necessary and proportionate
Under EU privacy rules, employers can only monitor messages when doing so serves a legitimate purpose and when less intrusive options would not work. As part of GDPR, European Data Protection Board has reinforced that monitoring needs to be proportionate to the problem being investigated. This is stricter than what employers face in many non-EU countries.
When monitoring may be justified
- The employer receives serious allegations, such as harassment, fraud, or data misuse.
- The employer has defined the scope and limited the search to relevant messages.
- Other evidence is unavailable or not enough to resolve the matter.
Whether monitoring is justified depends on the specific case, and a Slack channel, a Teams conversation and an email inbox carry the same privacy rules.
When monitoring is likely unlawful or high risk
These are the most common ways employers cross the line.
- The employer monitors messages on an ongoing or generalized basis.
- The employer reviews messages to track performance or productivity.
- No concrete suspicion exists before the employer begins reviewing messages.
- The employer reads private or clearly personal channels without strong cause.
- The employer relies on a weak, broad clause in the contract to read messages.
Owning the Slack or Teams account does not automatically make it lawful to read employee messages.
What employees need to know and what limits remain
Employees are typically told that work tools may be monitored, and policies typically describe when and how the employer might review messages during investigations. Even with that notice, employees retain privacy rights. A broad monitoring clause won’t cut it.
Safeguards HR teams typically apply
- Limit who can access the messages to a small, authorized group.
- If reviewing, review only messages relevant to what is being investigated.
- Avoid collecting unrelated personal data.
- Document why the monitoring was necessary and how it was limited.
Employers generally use these steps to demonstrate they acted within GDPR limits if the monitoring is later challenged. EU privacy rules also come up when employers handle a layoff.
TL;DR
- EU employers may monitor Slack or Teams messages during investigations only when doing so is necessary, proportionate, and targeted to a specific issue.
- Routine or blanket monitoring is not permitted.
- HR teams typically limit who can access the messages, review only what is relevant to what is being investigated, and document why the monitoring was necessary.