The wrong recipient is one autocomplete away.
Sendasta catches every email going to the wrong person — the competitor, the former client, the John Smith nobody meant to email — and warns you the moment before it lands. One last check, so you can catch the mistake yourself.
Free for personal use · No credit card · Works on Outlook web, desktop, and Mac
This email is addressed to 2 external organizations:
- acme.com
- competitor.com
Confirm this is intentional.
You start typing a name. Outlook fills in the rest. You attach the file, hit send, and a second later realize the autocomplete grabbed the wrong contact — the one with the similar last name, the old client, the personal address. By then it's gone.
Sendasta catches it before it leaves your outbox.
Three steps. Five minutes.
Install
Add Sendasta to your own Outlook in a few clicks, or roll it out to your whole team through Microsoft 365 Admin. Works on Outlook web, desktop, and Mac. No technical knowledge required.
Add your rules (optional)
Out of the box, Sendasta flags any email going to two or more unrelated outside companies, with nothing to set up. On Business, an admin adds the domains to always flag — competitors, former clients, personal addresses — once, for the whole team.
Send normally
When you click Send, Sendasta checks your recipients against your rules. If something looks off, it pauses and shows you why. If everything checks out, the email goes. You won't notice it most days. The day you do, it's worth it.
What it actually does
Catches recipients that don't belong
When the recipients on an email don't match — a competitor's domain mixed with your client's, a personal address mixed with a corporate one — Sendasta pauses the send and asks you to confirm. Checks the To line on every send, including Reply All; Business checks Cc and Bcc too.
- Checks every send, including Reply All
- Cc and Bcc checked on Business
- Works on Outlook web, desktop, and Mac
- Flags mismatched company domains
Enforces a rule, not a hope
Your admin adds the domains you don't want emails going to, ever. Competitors. Former clients. The journalist's address you accidentally added six months ago. Sendasta requires a deliberate "Send Anyway" — no silent slips.
- Requires a deliberate "Send Anyway" to override — no silent slips
- Trusted pairs to silence alerts for known-safe combos
One deployment, whole team
Roll out through Microsoft 365 Admin in about five minutes. No per-user setup, no end-user action. Add your company domain once in the admin console and everyone picks up your team's rules automatically.
- Deploy once through Microsoft 365 Admin Center
- No end-user action or setup required
- Works on Outlook web, desktop, and new Outlook for Mac
The numbers nobody likes to talk about
3 in 5
organizations lost data through an employee mistake on email in the past year.
Tessian & Ponemon, 2022
40%
of employees have sent an email to the wrong person.
Tessian survey of 2,000 workers, 2022
27%
of GDPR data protection incidents involve misdirected emails.
Abnormal AI, 2025
47%
of security teams learn about a misdirected email from the recipient, not their security tools.
Abnormal AI, 2025
One click is all it takes.
One misdirected email can end a client relationship that took years to build. Sendasta protects your whole team for $4 per user per month.
Simple, fair pricing.
For individuals who want to stop misdirected emails in their own inbox. No account, no sign-in.
- Real-time conflicting-domain warning
- One-click enable / disable
- Works on Outlook web, desktop & Mac
- Self-install in under 5 minutes
No account needed. Works immediately.
5-user minimum · e.g. 10 users = $40/month
Everything in Personal, plus team-wide rules and a central admin console.
- Everything in Personal, plus:
- Block specific domains for your whole team
- Internal-domain bypass list
- Trusted pairs to silence false alarms
- Cc & Bcc recipient checking
- Central admin console — set rules once
- Automatic rollout via Microsoft 365 Admin
- Priority email support
Starts with a 14-day free trial. Cancel anytime before it ends and you won't be charged.
Need something custom for a larger team or specific compliance requirements? Email info@sendasta.com — we'll figure it out.
Common questions
No. Sendasta only checks recipient addresses against your rules at the moment you click Send — it never reads the subject line, body, or attachments. Nothing is sent to Sendasta servers.
Sendasta works on Outlook on the web, Outlook for Windows, and new Outlook for Mac. It requires a Microsoft 365 account.
It warns. When you click Send, Sendasta checks the recipients against your rules and shows a popup if something matches — the wrong domain, a competitor, a mixed thread. You can fix the recipients, or send anyway if it's a false alarm. The decision is always yours.
No. Admins push shared rules to the whole team automatically. Sendasta is active in everyone's Outlook from day one, with your rules already applied.
14 days, full access. You add a card to start, but you won't be charged until the trial ends, and you can cancel anytime before then.
More questions? See the full FAQ or email us directly.
For IT and admins
Deploy Sendasta to everyone's Outlook in about five minutes through Microsoft 365 Admin Center — no end-user action, no per-person configuration. You set the rules once in the admin console and they apply to everyone.
Questions? A real person answers.
Pricing questions, custom setup, integration questions — send a message and you'll hear back within one business day.
We respond within 1 business day