Can My Employer See My Teams or Slack Messages?

Yes, with two qualifications that matter more than the yes. First, it is not your manager who can read them, at least not through anything built into Teams or Slack. It is whoever holds a specific compliance role or owns the workspace, and that is usually a small number of people in IT or legal. Second, nobody is reading as you type. Messages are retrieved after the fact, through search and export tools that exist for lawsuits, investigations and regulators, and that leave no trace you will see.

That is the shape of it. The details differ between the two products, and the details are what decide whether a deleted message is gone, whether a private channel is private, and whether anyone has to tell you. This page quotes Microsoft's and Slack's own documentation rather than paraphrasing it, then sets out what US law adds.

Microsoft Teams: where chats live and who can open them

Every Teams message is copied into an Exchange mailbox. Microsoft's retention documentation puts it this way: "Data from Teams chats is stored in a hidden folder in the mailbox of each user included in the chat, and a similar hidden folder in a group mailbox is used for Teams channel messages." The folders "aren't designed to be directly accessible to users or administrators," the page continues, "but instead, store data that compliance administrators can search with eDiscovery tools." Private channel messages, which used to sit in each member's mailbox, began moving to group mailboxes at the end of 2025. Meeting chats, recordings and transcripts are in scope too.

The tool that opens those folders is Microsoft Purview eDiscovery. Since 31 August 2025, when Microsoft retired the classic Content Search and the older eDiscovery experiences, it is one unified tool, and its permissions page names who can run it: members of the eDiscovery Manager and eDiscovery Administrator role groups. A Compliance Administrator can search but cannot preview or export by default. A Global Administrator does not get access to communication compliance by default either. None of those roles are things a line manager is handed.

What a manager might be shown is the Teams user activity report, and it is worth knowing exactly what it contains. Microsoft's report reference lists the columns: channel messages, posts, replies, urgent messages, chat messages, 1:1 calls, meetings organized and attended, audio, video and screen share duration, and a last activity date. Counts, not content. Names are hidden in those reports by default and have been since September 2021, unless a global admin switches the setting.

Three more routes exist, all role gated and all visible to whoever administers the tenant. Communication compliance scans chats and channels against policies for inappropriate text, sensitive data or conflicts of interest; usernames are pseudonymized by default and reviewers have to be opted in by an admin. The Teams export APIs feed archiving products such as Smarsh and Proofpoint, and require admin approved permissions. And a legal hold keeps "immutable copies" of everything, edits and deletions included.

Two edges people miss. Chats with guests and with people in other organizations are discoverable: for a meeting between two companies, Microsoft says "admins in both organizations can search for content in chat messages from the meeting." And when you leave, your chats stay in an inactive mailbox and remain searchable.

Deleted and edited Teams messages

Deleting a message removes it from your screen and not much else. Microsoft's retention page says a deleted message "doesn't go into the SubstrateHolds folder for 21 days," and messages in that folder "remain searchable by eDiscovery tools" until they are permanently deleted. The export API page confirms the same window: deleted messages "can be accessed using export APIs up to 21 days from the time of deletion." Under a retention policy or hold, the window becomes the policy period, and edited messages keep their previous versions.

The sentence to remember is Microsoft's own: "Messages visible in the Teams app are not an accurate reflection of whether they're retained or permanently deleted."

Slack: what each plan lets owners export

Slack draws its line by subscription rather than by role, and its export guide is unusually frank about it.

Slack states the purpose as "legal and regulatory compliance," and on Business+ asks owners to confirm that "appropriate employment agreements and corporate policies have been implemented." Standard exports include links to files rather than the files themselves; Discovery API exports include the files.

Three details that the plan table does not show. Retention decides whether deleted messages survive. Paid plans keep data "for the lifetime of your workspace by default," and the retention settings offer "Never delete messages, save edits," which records edits and deletions, or "don't save edits," which does not. Data deleted under a retention setting "is permanent." Slack Connect is readable by both sides. On Business+ and Enterprise, each organization can export the shared channels and DMs its members are in, and the Slack Connect guidance says the Discovery API "allows all organizations to read content in channels and DMs that they share with people outside of their company." Enterprise has native DLP that scans messages against rules, can hide a flagged message until it is reviewed, and notifies the sender if it is deleted.

Slack's position on ownership is one sentence in its privacy FAQ: "A Customer owns and controls all content submitted to their workspace." The customer is your employer.

Will you be told?

Not by the software. Microsoft's documentation describes no notification for an eDiscovery search. The only message a Teams user ever sees is "This message was deleted by an admin" when an administrator removes something, or a retention notice when a policy deletes messages in bulk.

Slack used to tell you. Under the compliance export that existed until April 2018, members were notified automatically when an export ran. From 20 April 2018 that stopped, and employers were left to do the notifying themselves. Slack's current pages do not describe any member notification at all; the nearest thing is a line in the export guide that "laws and policies may also require employers to notify employees of their use of export tools." Whether yours does is a question for the law section below and for your own handbook.

You can, however, look for yourself. Slack's privacy FAQ says members can open the workspace settings to see the owners and admins, the plan, the retention policy and the available export options. Five minutes there answers most of what this page covers for your own workspace.

What they cannot do

The ranking articles on this question tend to open with "everything" and then contradict themselves. The documented limits are these.

• No live reading. Content comes out through search and export after the fact. Microsoft notes "up to a 24-hour delay to discover Teams content."
• No manager-level content access. The reports a manager can be given show counts and durations. Content needs a compliance role.
• No status history. The activity report has a last activity date and a flag for "other activity," which includes changing your status. It does not record when you were away or for how long. Our page on whether your employer knows when you are idle on Teams covers that separately.
• No access by Microsoft or Slack themselves. Microsoft's security overview says "Microsoft doesn't have access to uploaded content." Slack describes itself as a processor acting on the customer's instructions.
• No reach into a personal account. A personal Teams account or a Slack workspace you own sits outside the employer's tenant. The one exception is a conversation between a personal account and a work account, which Microsoft stores in the work user's mailbox and a shadow mailbox, where the employer's rules apply.

What US law requires

No federal statute stops an employer reading messages on a system it provides. Two federal laws set the baseline and three states add a notice duty.

The Stored Communications Act, 18 U.S.C. 2701, prohibits unauthorised access to a facility that provides an electronic communication service, and then exempts conduct authorized "by the person or entity providing a wire or electronic communications service." Courts and commentators generally read an employer that provides the Teams tenant or Slack workspace as falling inside that exception. The Wiretap Act, 18 U.S.C. 2511, allows interception "where one of the parties to the communication has given prior consent," which is what the acceptable use policy you signed on day one provides.

New York requires private employers to give "prior written notice upon hiring" to employees whose email, internet use or transmissions are monitored, acknowledged in writing or electronically, with a posted notice as well, under Civil Rights Law 52-c. Penalties run from $500 to $3,000 per offense. Connecticut defines electronic monitoring as "the collection of information on an employer's premises concerning employees' activities or communications by any means other than direct observation" and requires prior written notice of the types of monitoring, under General Statutes 31-48d. Delaware requires either a daily electronic notice or a one-time acknowledged notice before monitoring email or internet use, under 19 Del. C. 705, with a $100 penalty per violation. Our guide to employee monitoring laws by state has the full wording for each.

The protection that does reach message content is the National Labor Relations Act. Section 7, at 29 U.S.C. 157, gives employees the right to act together for "mutual aid or protection," and the NLRB has long treated surveillance of those conversations, and rules banning employees from discussing wages, as unfair labor practices. The Board's general counsel issued a memo on electronic monitoring in 2022 and a successor rescinded it in February 2025; the underlying rule that an employer may not spy on protected concerted activity did not change. A Slack thread in which three colleagues compare pay is exactly the kind of conversation that rule protects, whoever can technically export it.

What to do with this

1. Treat every work account as retained. Not because someone is reading, but because the retention period is the employer's choice and, for Teams, at least 21 days even after you delete.
2. Check the Slack workspace settings page. It states the plan, the retention rule and the export options. If retention saves edits, deletions do not remove anything.
3. Ask for the monitoring notice. In New York, Connecticut and Delaware you are entitled to one. Elsewhere, the acceptable use policy is where the answer usually already sits.
4. Keep personal conversations in personal apps. A personal account on a personal phone is outside every mechanism described here. The guide to what an employer can see on a personal phone explains where that line sits.
5. Do not route around it. Moving work conversations to a consumer messaging app to avoid retention is usually a policy breach and, in regulated industries, a record keeping violation that lands on the company.

If you are the employer

Three things keep message access defensible. Write down who holds the compliance roles and why, because the question "who can read my messages" has a precise answer and a vague one reads as the worse of the two. Put the retention period in the monitoring notice, since in New York, Connecticut and Delaware the notice is mandatory anyway and the retention period is what employees actually want to know. And keep eDiscovery for investigations and legal holds rather than curiosity: the privacy line and the monitoring policy template cover how to say that in a policy people will believe.

Key takeaways

• Teams chats are copied into Exchange mailboxes and searchable through Purview eDiscovery by holders of the eDiscovery Manager or Administrator roles. Managers are not given those roles by default.
• The Teams activity report a manager can see contains message counts, meeting durations and a last activity date, not content.
• Deleted Teams messages remain searchable for at least 21 days, and for the full retention period if a policy or hold applies.
• Slack exports of private channels and DMs are plan dependent: not without Slack's approval on Free and Pro, self-serve after primary owner approval on Business+, and through the Discovery API on Enterprise.
• Neither product notifies you of a search. Slack stopped automatic export notices in April 2018.
• Chats with guests, external meetings and Slack Connect channels are readable by both organizations.
• Federal law permits reading on employer provided systems. New York, Connecticut and Delaware require written notice. The NLRA protects wage and working condition discussions from surveillance.
• A personal account on a personal device is outside all of this, except where it talks to a work account.