FAQ
Straight answers.
If something here reads like it is dodging the question, tell me and I will rewrite it.
Do I need an API key?
No. Doppel ships with a local model it can set up for you, and drafting works entirely on your own machine with no key, no account, and no per-word cost.
You can supply your own Anthropic key if you want a cloud model instead. It is faster and better at long documents. That is your key, billed to you by them. After you enter it, it goes straight into Windows Credential Manager: never written to disk in the clear, never in the database, never in a log, and never sent anywhere but the provider it belongs to. If you already run Ollama, Doppel will use that rather than installing anything.
Does it work offline?
Yes, if you are using a local model, which is the default. Drafting, dictation, meeting transcription, and document summaries all run with the network unplugged.
The things that need a connection are the ones that obviously do: downloading the app or a model the first time, connecting an email account, and the optional cloud model.
What does it cost?
Nothing during the beta. Afterwards there will be a paid tier, and anyone who installed during the beta keeps a free base license permanently.
Local models stay free and unmetered regardless. There are no credits, no token allowance, and nothing that runs out mid-draft. If you use your own API key for a cloud model, that provider bills you directly and Doppel takes no cut.
Where is my data, exactly?
One folder: %APPDATA%\twin\, in your Windows user
profile. Paste that into File Explorer and you are looking at
everything Doppel knows about you. Most of it is a single SQLite
file, twin.db; alongside it sit your meeting audio,
the encrypted email corpus, voice profiles, mind maps, backups,
and the error log.
Keys and account tokens are encrypted separately through Windows DPAPI, tied to your Windows login. There is no cloud copy of any of it — no server of ours holds your content. The full architecture is here.
Can it write as someone who is not me?
Not by design, and this is a line I will not move. Doppel calibrates on writing you provide as your own. It has no feature for cloning a third party's voice from their emails, and voice cloning is consent-gated on the speaker.
It is not built to impersonate anyone, to defeat an authentication check, or to produce something passed off as another person's words. If that is what you need, this is the wrong tool and I would rather you used a different one.
Is my writing used to train a model?
No. Nothing you give Doppel trains anything shared with anyone. Your profile shapes prompts on your own machine; it is not training data, and nothing in the app uploads it. The only way any of your writing reaches me is if you paste it into a bug report and press Send.
If you supply your own cloud API key, your prompts go to that provider under their terms, which is worth reading, and a reason some people stay on local models.
Will it send an email without asking?
No. Every message is a draft until you approve it, and outbound capability ships switched off.
One honest caveat, because it exists and I would rather you heard it here: Teams chat has an unattended-reply setting. It is off by default, you have to turn it on for a specific person, and it does not apply to email at all. Nothing sends unless you went looking for that switch.
Why does Windows say it is unsafe?
Because it is from a publisher Windows has not seen enough of yet, not because anything is wrong with the file. Code signing through Microsoft's Azure Trusted Signing is in progress, and reputation still accrues from zero afterwards.
The download page shows the exact dialog, what to click, and the checksum so you can verify the file independently of Windows' opinion of me.
Mac or Linux?
Not yet, and I would rather say that plainly than list it as "coming soon". Windows is where the people I built this for actually work. A Mac build is possible later; it is not in progress today.
How do I get rid of it?
Uninstall through Windows Settings like any other application.
That removes the program but deliberately leaves your data
behind: %APPDATA%\twin\ stays where it is, so
a reinstall — or an update, which runs the uninstaller first —
does not wipe your profile and history.
If you want it actually gone, delete that folder yourself after uninstalling. Export a backup first if you might want any of it back, because nothing else has a copy.