SubjectTag
Your team agreed every email starts with [Internal] or a project code. Nobody remembers. SubjectTag puts the convention on a button — one click to tag, never doubled up.
€19 one-time · free tier, free forever · 30-day money-back
Naming conventions die in the subject line
The convention made sense in the kickoff meeting: prefix internal mail
with [Internal], flag requests with [Action required], start project mail
with the project code so filters and searches work. Two weeks later half
the team forgets, the other half types
[internal][Internal], and the filters catch nothing.
SubjectTag turns the convention into buttons. One click
prepends the prefix — and clean-prefix detection means clicking twice never
stacks duplicates; clicking an applied tag removes it. Pro adds your own
prefixes, project-code templates like ACME-{nnn}:, team
import/export so everyone runs the same set, and an optional gentle on-send
nudge when a subject matches no convention.
Free vs Pro
Free covers the four classics. Pro makes the convention yours — codes, custom tags and a whole-team setup.
| Feature | Free | Pro €19 |
|---|---|---|
| 4 prefix buttons: [Internal] [Confidential] [Action required] [FYI] | ✓ | ✓ |
| One click to add, one click to remove | ✓ | ✓ |
| Clean-prefix detection (no [Internal][Internal]) | ✓ | ✓ |
| Custom prefixes | — | ✓ |
| Project-code templates (e.g. "ACME-{nnn}:") | — | ✓ |
| Team conventions import / export | — | ✓ |
| Optional on-send nudge when the subject matches no convention | — | ✓ |
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.
Tag as you write
Composing an email, click the prefix it needs — done. Click again to take it off. Free forever — not a trial.
Unlock Pro when you need it
Buy once on Gumroad, paste your license key into the pane. Custom prefixes and team sharing unlock instantly.
Installing SubjectTag
In Outlook: Get add-ins › My add-ins › Add a custom add-in, then add the SubjectTag manifest from URL or file. A SubjectTag button appears when you're composing a message.
Coming to AppSource: SubjectTag is being submitted to Microsoft's add-in marketplace, after which it installs in one click from inside Outlook. Sideloading works today.
FAQ
What stops the [Internal][Internal] mess?
SubjectTag parses the subject before touching it. If the prefix is already there — even typed by hand, even with different capitalisation — clicking the button removes it instead of stacking another copy.
How does my team get the same prefixes?
Pro exports your conventions to a small JSON file; colleagues import it and get identical buttons and templates. One file in the team wiki keeps everyone in sync — no server, no admin console.
Is the on-send nudge annoying?
It's optional, off by default, and it's a prompt — not a block. When a subject matches none of your conventions, Outlook asks once before sending; you can send anyway with one click. It needs a recent Outlook (Smart Alerts support) and stays silent where that's unavailable.
Refunds?
30-day money-back guarantee, no questions asked — reply to your Gumroad receipt or email [email protected].