Privacy

Last updated 27 July 2026

Halo holds your personal context: what you are working on, who you work with, what you have decided. That only works if you know exactly what happens to it. This page says what we store, where it physically lives, who can technically reach it, and how to take it out or delete it. Where the honest answer is less flattering than the marketing version, the honest answer is below.

Who we are

Halo is operated by BRAIN 2.0 LTD. ("we", "us"), a company registered in England and Wales, company number 15493887, at 71-75 Shelton Street, Covent Garden, London, WC2H 9JQ, United Kingdom. We are the data controller for the information described here. For anything on this page, write to info@braintwopoint0.com.

What we store

Your account

Your email address and a hashed password, held by our authentication provider. We never see your password in readable form. If you use a connected AI, we also store the OAuth grants that let it reach your brain, so that you can revoke them.

Your brain

The facts and entities you or your connected AI capture, plus the structure around them: categories, the episode each fact came from, when it was learned, when it was retired and by which channel. That provenance exists so you can always see where something came from and undo it.

Your brain is stored in a database file that belongs to you alone. It is not pooled with other users' content, and it is not used to build shared models, indexes or datasets.

Diagnostics

We may record that a tool was called, whether it succeeded, roughly how long it took, whether a search returned any results, and how old the top result was. These carry a one-way hash of your account identifier rather than the identifier itself.

Diagnostic records deliberately contain no fact content, no search queries, no category names, no episode labels and no URLs. Category names are excluded specifically because some of them (for example health or finance) would reveal something about you by existing. Counts and timings are grouped into ranges rather than recorded exactly.

Payments

If and when Halo charges for hosting, payments are handled by Stripe. Card details go to Stripe directly and never reach our servers; we keep only the subscription status needed to know what your account is entitled to.

What we do not do

• We do not sell your data, or share it for advertising.
• We do not train models on your content, and we do not let anyone else do so.
• We do not read your brain content, except in the narrow support case described below.
• We run no advertising or tracking cookies, and no third-party scripts in your dashboard.

Halo does not send your content to an AI

This is the part most worth understanding, because it is unusual.

Halo performs no AI inference of its own. When you ask your assistant something and it recalls from Halo, your assistant connects to Halo, using yoursubscription with that provider, and reads the facts it asked for. We never send your content to OpenAI, Anthropic, Google or anyone else, and we hold no API keys with them.

The consequence is worth stating plainly: what your assistant then does with the facts it read is governed by your relationship with that provider, not by this policy. Choosing which assistant to connect is a decision about whose terms apply to that leg of the journey. We cannot control it and we do not claim to.

Halo also computes the mathematical representations used for searching your brain on our own server, using a small model that runs locally. Your fact text is not sent anywhere for that either.

Two features that read more than you might expect

The voice profile

During onboarding you can ask your assistant to build a writing-style profile. If you agree, your assistant reads a sample of your recent sent email through the connection you have already given it — Halo has no access to your mailbox — and stores only abstracted patterns: sentence length, how you open and close, habitual short phrases. Raw email text, subjects, recipients and quoted threads are never stored in Halo. You can skip this stage, and you can delete the resulting profile like any other fact.

Source checking

When a fact depends on a pending outcome, you can ask Halo to fetch the page where that outcome would be published, so your assistant can confirm it. Halo requests only the address you or your assistant supplied, and refuses addresses on private or internal networks. The operator of that page will see a request from our servers.

Where your data lives, and how it is protected

Brain data is stored on encrypted block storage in London. Accounts are held by our authentication provider, also in London. Diagnostic records, when collected, are processed in the European Union. All connections to Halo use TLS.

Being precise about encryption: your data is encrypted at rest at the storage layer, and encrypted in transit. It is not end-to-end encrypted, and Halo is not a zero-knowledge service. Because Halo has to be able to search your facts and serve them back to your assistant, they exist in readable form on the server while it runs, which means our operator is technically capable of reading them. We do not, other than in the support case below, and we never do so to build products, models or datasets. We would rather tell you that than imply a guarantee the architecture does not provide.

The narrow support case: if you contact us about a specific problem and it cannot be diagnosed any other way, we may need to look at the affected records to fix it. We will ask you first.

Who else is involved

We use a small number of providers to run Halo. They process data on our instructions only:

• Fly.io — hosting and storage for your brain (London).
• Supabase — account authentication (London).
• Vercel — hosting for the dashboard.
• PostHog — diagnostic records, when collected (European Union).
• Stripe — payments, if and when Halo charges.

The AI assistant you connect is not one of our providers. That is your own account with that company, and your agreement with them covers it.

How long we keep things

Your brain is kept until you delete it. Deleting a fact removes it immediately; archiving or merging one keeps the row so your history stays honest, and you can restore it. Deleting your account deletes your brain file, and the account record with it. Backups, where they exist, are overwritten on a rolling basis.

Your rights

Under UK data protection law you can ask for a copy of your data, correct it, delete it, take it elsewhere, restrict how we use it, or object to a particular use. Two of these are built into the product rather than being a request you have to make:

• Export — your whole brain, as JSON or Markdown, from your dashboard, whenever you like. It is a plain file with no proprietary format, because leaving should not require our permission.
• Delete — individual facts from the dashboard or through your assistant, or the whole account from your account settings.

For anything else, write to info@braintwopoint0.com. If you are unhappy with how we have handled it, you can complain to the UK Information Commissioner's Office at ico.org.uk.

Cookies

Halo sets one cookie, which keeps you signed in. There are no analytics, advertising or cross-site tracking cookies, so there is nothing here to consent to and no banner to dismiss.

Children

Halo is not intended for anyone under 16, and we do not knowingly create accounts for them.

Changes

If we change this policy we will update the date above. For anything that materially changes what we collect or who can reach it, we will tell you by email before it takes effect rather than quietly editing this page.