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AI data leakage 7 min read

Where is your prompt while you type it?

Between the first keystroke and the send button, your text exists in more places than the interface suggests. Drafts, sync, extensions, keyboards.

Someone typing a prompt in a browser window
Quick answer

As you type, your text sits in browser memory and usually in the site's local storage, so your draft survives an accidentally closed tab. Some services also sync drafts to the server so you can continue on another device. Alongside that, anything with read access to the page can see the input field: other browser extensions, third-party writing assistants that send text to their own servers, and predictive keyboards on mobile. Send is not the first moment your text exists somewhere other than your head.

01

Your draft lands in browser local storage before you send anything

02

Some services sync drafts to the server for cross-device continuity

03

Any extension with page read access can see the input field

04

Third-party writing assistants are a second processor in the same path

05

Send is the last moment to intervene, not the first point of exposure

Most conversations about AI and data start at the send button. Before that, nothing seems to be happening: you type, you think, you delete a sentence, and only when you press the button does anything leave.

True for the model. Not true for the text.

In browser memory

The moment you type a character, it is in browser memory. Unavoidable, and on its own uninteresting.

What sits alongside it is more interesting. Nearly every modern web application persists your input to the browser's local storage as you go, so a half-written message survives a crashed tab or a mis-clicked close button. Nobody objects to that feature, and nobody reads it as a data flow either.

The consequence is that your draft outlives the tab. It is on the machine, in that site's storage, until the site clears it. On a shared workstation that is worth knowing.

Sync to the server

Some services go a step further. Drafts are synced to the server so you can pick up on your phone where you left off on your laptop.

On those services, "send" is no longer the moment your text leaves the device. That already happened, incrementally, while you typed. This varies by provider and is rarely prominent in the terms, so if it matters to your assessment, it is a question for the vendor rather than an assumption.

Everything else watching the same page

The largest category in practice, and the least discussed.

A browser extension with read access to the page can see what is on that page. Not a vulnerability: the permissions it was granted at install. That covers translation helpers, writing assistants, screenshot tools, password managers, and the extension somebody installed two years ago for one task and has not thought about since.

So the question is not whether extensions can see the field, but which ones exist and who approved them. See browser extensions are AI tools too.

Two cases deserve singling out:

Third-party writing assistants. The checker built into the browser runs locally. Standalone assistants that improve grammar and tone typically send your text to their own servers to generate those suggestions. That is a second processor, with its own retention and its own jurisdiction, stacked on the AI tool you were already typing into.

Mobile keyboards. Keyboard apps with predictive text and cloud sync learn from what you type. On a work phone running a personal keyboard app, that is a processing operation nobody assessed.

Why this is more than trivia

For a DPIA it matters because the processing chain is longer than the paperwork suggests. You assessed the AI vendor, and there may be three parties in the path: the extension, the writing assistant, and the assistant you meant to use.

For daily practice the conclusion is more reassuring than it sounds. The input field is not a waiting room where text does not yet exist. It is the first place the text exists, and simultaneously the last place anyone can change it without having to undo something somewhere else.

Which is exactly why the moment of typing is the interesting one. Not because it is where most goes wrong, but because it is the only point at which the text is still yours.

FAQ

Common questions

Is my prompt sent while I type?

Not to the model, which receives it only when you send. But your text is already in browser memory and typically in the site's local storage by then, and some services sync the draft to the server so you can continue elsewhere.

Can other browser extensions read my prompt?

An extension with read access to the page can in principle see everything on that page, including the contents of the input field. That applies to any extension holding those permissions, not only AI-related ones. It is a good reason to know which extensions are approved in your organisation.

Do spell checkers read along?

The browser's built-in checker runs locally. Some third-party writing assistants send your text to their own servers to generate suggestions. That is a second processing operation with its own vendor and its own retention, layered on top of the AI tool.

Does my draft survive if I close the tab?

At most AI services, yes. It is a convenience feature: your half-written prompt is still there when you return. It also means the text outlives the tab and stays on the machine until the site clears it.

What should I actually do about this?

Most of it is ordinary web application behaviour and not worth fighting. What matters: know which extensions hold page read access, do not layer a third-party writing assistant on top of sensitive work, and treat the input field as a place where the text already exists rather than a waiting room.