Outbound email monitoring for Microsoft 365

Reviewing the email employees send from company accounts for content that creates legal, financial or reputational risk, and alerting the people responsible (compliance, HR, legal, finance) when something needs attention. It is different from spam and phishing filtering, which protects inboxes from incoming mail, and from data loss prevention (DLP), which mostly matches patterns like card numbers to block or encrypt a message.

• Payment fraud. New or changed bank details, urgent wires, gift-card requests: the business email compromise pattern, whether your own mailbox was compromised or an employee is acting on a fake request.
• Discrimination and retaliation. Hiring, pay or promotion decisions tied to age, pregnancy, disability or another protected characteristic, or action against someone who complained.
• Harassment and conduct. Threats, slurs, sexual advances, or a contemptuous reply to a customer.
• Data leaving the company. Customer lists, pricing, source code or financial files sent to personal accounts, often by someone about to leave.
• Credentials. Passwords, API keys and connection strings pasted into email.
• Legal exposure. Admissions of fault, side deals kept out of contracts, backdating, collusion with competitors, bribes.
• Confidential information. Non-public results, deals or layoffs sent to people with no reason to have them.
• Evading oversight. "Delete this", "call me on my personal phone so there’s no record", splitting purchases to dodge approval.

Just as important is what it should leave alone: quotes, contracts sent for signature, invoices, meeting invites, newsletters, out-of-office replies, and blunt but ordinary internal discussion. A tool that flags those buries the real alerts, and a queue nobody reads protects no one.

Generally, yes, for company email systems used for work, but expectations differ by place and the details matter. In the United States employers commonly monitor company accounts, and some states (New York, Connecticut and Delaware among them) require employees to be told in advance. In the UK and the EU, monitoring must be necessary, proportionate and transparent, usually documented in a data protection impact assessment, and in some countries agreed with a works council first.

Two practices help everywhere: tell employees, in writing, that work email is reviewed for compliance, and collect as little as possible. Leave alone the communications the law protects, such as an employee’s report to a regulator. This is general information, not legal advice; ask your counsel what applies to you.

Microsoft Purview Communication Compliance. Microsoft’s own tool, with policies built from keyword dictionaries, sensitive information types and trainable classifiers. Powerful if you own E5-level licensing and have someone to build and tune policies. See how it compares with Aftercomm.

Exchange mail flow rules and DLP. Good at patterns, such as blocking card numbers or copying mail with certain words to a reviewer. Poor at meaning: the riskiest emails rarely contain a forbidden word.

Journaling and archive platforms. Essential for regulated recordkeeping, and searchable after the fact, but built for retention and eDiscovery rather than prompt alerts.

AI review. An AI model reads each sent email against a written policy and explains each flag in a sentence. It catches risk that has no keyword, and it can be tuned to keep false alarms low. Aftercomm works this way.

The failure mode of every monitoring program is too many alerts. Three things keep it useful: judge meaning rather than keywords; grade severity so only urgent issues interrupt someone immediately while the rest go to a digest; and keep a tight, written policy of what is worth a look. Assume some false positives anyway. A reviewer dismissing a few a week is a healthy program; one dismissing hundreds has stopped reading.

Aftercomm connects to Microsoft 365 with two read-only permissions, checks the Sent Items of the mailboxes you choose every few minutes, and reviews each new email with Claude, from Anthropic, which never trains on it. High-severity flags alert your reviewers within minutes; everything else arrives in a digest. Aftercomm never stores message content, alerts never contain the email, and every time a reviewer opens a flagged message it is logged. Pricing is $5 per monitored mailbox per month, plus AI usage at Anthropic’s list price with no markup, roughly $0.20 to $0.50 per 1,000 emails.

See how it works, read the Trust center, or see a sample alert.