Architecture, measures, commitments

Security you can actually check.

Bostaji reads your emails, suggests actions, and lets you decide. For that trust to be earned, here is what is in place — concretely, not in marketing terms.

Three commitments, three proofs

Your emails stay with you

Bostaji is an application that runs on your own computer. Your emails stay in your mailbox, never on a Bostaji server. If you use several devices, syncing is private: we only ever see packets that no one but your own devices can read.

Bostaji suggests, you decide

No automatic sending. No permanent deletion. No draft generated while sorting. When Bostaji is unsure, it asks you. When you correct it, it learns. You stay in charge.

You see what happens

In the Stats menu you get the full log of decisions: the reason for each action, the confidence level, what you validated or corrected. No black box — you can call us out if you spot a gap.

The architecture in brief

Bostaji is built around a simple principle: do as much as possible on your own computer, and send elsewhere only what is strictly necessary to understand your emails.

On your computer

The Bostaji app connects to your mailbox with your permission. It reads your incoming emails, sorts them, applies your rules, and carries out the actions you have validated (move to a folder, archive, mark as read). Your rules, your preferences, your decision history and your corrections stay in a dedicated folder on your machine. Your access keys to your mailbox are kept in your operating system's secure vault (Keychain on macOS, DPAPI on Windows) — never in plain text in a file that other applications could read.

To the AI engine in France

To understand the meaning of an email (“is this urgent? a newsletter? an invoice?”), Bostaji sends the Mistral engine, provided by Mistral SAS, a French company based in Paris: the subject of the email, its body, and if needed the text of an attachment to resolve a classification doubt (or when you ask to read it). That text is never stored. Not your access tokens, not your contacts, not your drafts, not your history. Mistral does not use your emails to train its models, that is a contractual condition.

Between your devices (if you enable sync)

If you use Bostaji on several computers (for example a work machine and a personal one), your rules, preferences, history and corrections can be synced. Before leaving your machine, this data is encrypted with a key that only exists on your devices. The server that carries it sees packets it cannot read. Not your emails — only your rules and preferences. Hosted in the European Union, never in the United States.

The concrete measures

On the technical side, here is what is in place. Whenever a specialist term is used, it is explained.

Network communications encrypted in transit (TLS). All communications between Bostaji and the outside world (your mailbox, Mistral, the sync server) go through TLS, the standard encryption protocol of the secure web — the same one that protects your communications with your online bank.
Data encrypted at rest on the sync server (AES-256). The packets synced between your devices are already end-to-end encrypted, but on top of that the server stores them encrypted a second time with AES-256 (military-grade standard). A double layer of protection.
Your mailbox access keys in the system vault. Keychain on macOS, DPAPI on Windows. Your access keys are never stored in plain text in a file that other applications could read. They are never sent to a third-party server.
No automatic email sending. Bostaji never triggers a send without your explicit validation. When Bostaji prepares a draft reply — a feature available on every plan — you are always the one who clicks “send”.
No permanent email deletion. Whatever the provider, Bostaji never uses permanent deletion. The worst it can do is move an email to the trash, where it stays recoverable (by default 30 days on Gmail).
Human validation for sensitive actions. When there is any doubt about how to classify an email, Bostaji asks you rather than deciding on its own. The doubt threshold is adjustable — you can tighten or loosen it depending on your confidence.
A trail for every decision. The Stats menu in the app shows every decision made, its reason, its confidence level, its risk level, and whether you validated or corrected it. You can disable a rule in one click, change a behaviour, or reset everything.

Independent verification

Bostaji is in closed private beta, during which the app runs in the Testing mode of Google's official procedure for applications that connect to Gmail. Before the public opening, Bostaji goes through two independent validation steps:

Identity verification by Google (Production verified procedure): Google verifies the publisher's identity, the domain, and the legitimacy of the application.
Independent security audit (CASA Tier 2): a specialised laboratory recognised by Google audits the architecture, the technical measures, and compliance with the security standards that apply to applications accessing sensitive data.

Both steps are under way. Once they are complete, the Google caution screen currently shown to beta testers will disappear automatically. If you are a beta tester, here is how to get past that screen with peace of mind.

What Bostaji does not do, and will not do

A few commitments we keep today and will keep tomorrow. These are product rules, not intentions.

Bostaji never sells any personal data, to anyone, ever.
Bostaji does not share any data for advertising purposes.
Bostaji does not build marketing profiles from your emails.
Bostaji does not use your emails to train its AI models, and does not let third parties use them for that purpose either.
No employee or contractor of Bostaji's publisher reads the content of your emails, unless you explicitly authorise us to (for example, if you send us an email quoted in a support ticket).

Going further

For the legal detail of each measure, the GDPR legal bases, the full list of subprocessors, your rights and how to exercise them, see the full privacy policy.

A question about a specific point? Write to us directly, we get back to you quickly.