Privacy: what leaves your Mac
Last updated 2 October 2026
fractionalflow records your screen to build a journal of your work. That is sensitive, and more so when the work belongs to several clients. Two promises shape the app: nothing about one client's work should reach another client, and nothing about any client's work should reach us.
This page says what is stored where, what leaves your Mac, and when.
What stays on your Mac
Recordings and your timeline are stored locally on your Mac. We do not run a server that receives them. You can pause recording from the menu bar, list apps that are never recorded, and delete recordings and data from the app's folder.
What leaves your Mac
| What | Where it goes | When |
|---|---|---|
| Screen observations, block text, category names and prompts | The AI provider you pick: Gemini, Claude, ChatGPT, or a local model through Ollama or LM Studio | Always, while recording. With a local model the analysis runs on your Mac. |
| One client's activity, with other clients' names masked | The same AI provider | When you click Draft update |
| Usage events from a fixed list of properties, with your Mac's hardware model | PostHog, our analytics provider | Unless you turn analytics off in Settings |
| Support messages, the email address you type, and the debug log if you tick it | PostHog, which hosts our support inbox | Only when you send a support message |
| Host names of sites you visited | Google's favicon service, then the site itself | Only if you turn on site icons in Settings. It is off by default. |
| Timesheets as CSV or Markdown | Wherever you save them | Only when you export |
Usage statistics
Usage events tell us which parts of the app are used: tabs opened, recording started or paused, counts and durations. They pass through an allowlist, so a property that is not on the list stays on your Mac. Events never carry block titles, summaries, category names, visited sites or chat answers. The device is identified by its hardware model (for example Mac15,3), never by your computer's name.
You can turn usage statistics off in Settings.
Support messages
When you send a support message we receive the message and the email address you type. The debug log is unticked by default. If you tick it, you see a preview of exactly what will be sent, and it is not sent at all if you have turned analytics off.
How clients are kept apart
Client updates. Draft update masks every other client before the prompt leaves your Mac, and again on the model's answer. It masks archived clients too. It leaves alone the client you are drafting for and your own company.
The mask is built from each other client's full name, each word of a multi-word name, its domains, its categories and its keywords. It catches possessives, plurals, compounds and host names, and replaces each with “[another client]”.
Shared blocks. When a block of time overlaps two clients, its title and summary describe both clients' work. On a timesheet that line appears as “Shared block” with no description. Its times and minutes are unchanged, so totals and invoices still add up. Exports and the update draft read the same lines, and observations from shared blocks are not sent to the AI provider for a draft.
The limits
- Once you choose a cloud AI provider, what the app sends for analysis is handled under that provider's terms. Choose a local model to keep analysis on your Mac.
- Masking works from the names, domains and keywords you have given each client. A name it does not know, such as a person at another client, is not masked.
- The mask is deliberately broad. If one client is called “Halden Freight”, the word “freight” is masked in your other clients' updates.
- No filter catches everything. Read every draft and export before you send it.
This website
If you join the waitlist, we store your email address, the time you joined and which form you used. It is kept with Vercel, which hosts this site, and used for one thing: to tell you when fractionalflow is available. Ask and we will delete it.
This site sets no cookies and runs no analytics or advertising scripts. Fonts are served from this site, not from a third party. Vercel keeps standard server logs for requests to the site.
Contact
Questions about privacy, or a request to delete your waitlist entry: jared@flowcos.com.