One inbox for Gmail and Outlook. Without the duct tape.
Run Workspace and Microsoft 365 from a single window on your Mac. STAMP unifies them, triages them, and replies from the right account every time.
No browser tabs. No duplicate windows. One keyboard surface. Inbox zero, every single day, across both providers.
No credit card · macOS · 28-second setup
The honest version
Three problems specific to gmail + outlook.
Gmail in one tab. Outlook in another. Cognitive split.
Every time you check email you pay a tax on context switching between two apps that work nothing alike.
Apple Mail can show both. But it's the worst client for both.
Apple Mail's Gmail support is decent. Its Outlook support is decent. Its triage support is non-existent.
Replying from the wrong account once is enough.
Most clients don't get the alias right. STAMP detects the originating account and replies from it without asking.
How STAMP solves it
Three features. Mapped to your day.
STAMP didn't ship 47 features. The six it did ship cover this whole problem, from triage to send.
Native Gmail and Outlook. One queue.
Connect via OAuth in 28 seconds each. STAMP speaks both APIs natively — no IMAP fallback, no quirks, no broken threads.
Reply from the right provider, automatically.
Gmail thread? Reply leaves from Gmail. Outlook thread? Outlook. STAMP detects the originating account and routes the send through it.
One shortcut surface. Both providers.
J/K to move. R to reply. ⌘+K to jump. The shortcuts work identically across Gmail and Outlook threads. Your hands don't have to relearn anything.
Why running Gmail and Outlook side by side is broken
Plenty of people have a Gmail and an Outlook account. The Gmail is personal or freelance. The Outlook is corporate. Most days, both matter. Neither provider's native client handles the other one well — Gmail web treats Outlook as a foreign organism, and Outlook desktop treats Gmail as a slightly suspicious external server.
Apple Mail can technically connect to both. But Apple Mail is a list, not a triage tool. You still get a flat stream of every thread ranked by arrival time, and you still pay the tax of figuring out which seven of these eighty unread threads matter today.
STAMP solves the integration problem by speaking both APIs natively. Gmail labels round-trip correctly. Outlook categories round-trip correctly. Threads are not duplicated. Read state is consistent across devices. Replies leave from the right provider. The unification is real, not cosmetic.
How a Gmail + Outlook morning works in STAMP
8:42 a.m. STAMP opens. The headline reads 'Seven need attention. Two are from your Workspace. Five are from Microsoft 365.' Both providers, one queue, ranked by signal.
9:00 a.m. You handle the Microsoft 365 threads first because three of them are tagged Reply needed by your manager. The replies leave from the corporate domain. ⌘+Return sends each one in under a minute.
9:08 a.m. Two Gmail threads from clients. You reply from your Workspace domain — Gmail's standard alias mechanism, but exposed through STAMP without you having to think about which 'send as' to pick.
9:13 a.m. Done. You close STAMP. The 41 unread Outlook newsletters and 22 Gmail digests are still there, in a separate quiet view, and you'll never read them.
Things that get measurably better
No more duplicate-thread hell. Apple Mail loves to show the same thread twice if it landed in both Gmail and Outlook somehow. STAMP de-duplicates threads at the message-id level so you never reply twice.
No more search-twice. The unified search hits both providers in parallel and returns one ranked list. Filter to one provider with a keystroke if you need to.
No more 'wait, what's my Outlook calendar?' STAMP surfaces calendar context from both providers so a thread mentioning a meeting links to the right calendar entry.
No more 'reply from the wrong account.' The originating account drives the reply. The cognitive load goes to zero. The brand consistency goes to one hundred.
“I have personal Gmail and a corporate Outlook account. STAMP is the only tool that handles both like first-class citizens.”
Early access user · Director of Product
FAQ
Three questions you'd ask first.
Does STAMP support Microsoft 365 with conditional access policies?+
Yes. STAMP authenticates via OAuth and respects conditional access. If your org enforces device compliance, STAMP plays nicely. Check with IT before connecting if your org has a strict allow-list of apps.
Will Gmail labels and Outlook categories sync correctly?+
Yes. STAMP round-trips both. A Gmail label applied in STAMP is visible in the Gmail web app. An Outlook category applied in STAMP is visible in the Outlook desktop app. The same thread can carry both without conflict.
What about my calendar?+
Both Google Calendar and Outlook Calendar surface as inline context inside threads. A direct calendar UI is on the roadmap; today STAMP focuses on the email triage layer and links to the calendar app for scheduling actions.
One last thing
Tomorrow's inbox is going to look exactly like today's.
Unless you change the tool.
Get early access, freemacOS · 28-second setup · No credit card