SendCheck
The email safety net. SendCheck inspects every message at the moment you hit Send — missing attachments, external recipients, your own checklist — and stops the embarrassing ones before they leave.
€39 one-time · free tier, free forever · 30-day money-back
"Please find attached…" — and nothing is
Everyone has sent it: the email that promises an attachment and delivers none. Or the internal draft that went to a client. Or the reply-all to forty people. None of these are skill problems — they're attention problems, at the exact second your attention is already on the next task.
SendCheck pays attention for you. Built on Outlook's native on-send events, it checks the message the instant you click Send and prompts you only when something looks wrong. You can always choose to send anyway — it's a seatbelt, not a roadblock. The attachment check understands English, Dutch, German and French.
Free vs Pro
Free catches the classic mistakes. Pro lets you encode your team's own rules.
| Feature | Free | Pro €39 |
|---|---|---|
| Missing-attachment prompt (keywords in EN/NL/DE/FR) | ✓ | ✓ |
| External-domain notice | ✓ | ✓ |
| First-time-recipient warning | — | ✓ |
| Custom keyword lists | — | ✓ |
| Custom pre-send checklist (your own questions) | — | ✓ |
| Empty-subject check | — | ✓ |
| Reply-all guard (warn above N recipients) | — | ✓ |
How it works
Install the free add-in
Two minutes, no account, no card. Add it via Outlook's Get add-ins dialog — see the install guide.
Use the free checks
Attachment and external-domain checks run on every send, automatically. Free forever — not a trial.
Unlock Pro when you need it
Buy once on Gumroad, paste your license key into the settings pane. Pro checks activate instantly, on all your devices.
Installing SendCheck
In Outlook: Get add-ins › My add-ins › Add a custom add-in, then add the SendCheck manifest from URL or file. The checks run automatically on send; a settings pane lets you tune them.
Coming to AppSource: SendCheck is being submitted to Microsoft's add-in marketplace, after which it installs in one click from inside Outlook. Sideloading works today.
FAQ
Can it block me from sending?
No — by design. SendCheck uses Outlook's store-compatible "prompt" mode: it warns, you decide. It's there to catch slips, not to get in your way.
Which Outlook versions does it work with?
SendCheck uses Outlook's Smart Alerts (on-send events), available in the new Outlook for Windows, Outlook on the web, Mac, and recent Microsoft 365 desktop builds. Honest note: very old perpetual-license Outlook versions don't support on-send events.
Does it read my email on a server somewhere?
No. All checks run locally inside Outlook via Microsoft's API. Your messages, recipients and settings never leave your mailbox — settings are stored in Outlook's own roaming settings. See the privacy policy.
Refunds?
30-day money-back guarantee, no questions asked — reply to your Gumroad receipt or email [email protected].