TrustPrompt logoTrustPrompt
Redact Personal Data in the Browser, Before a Prompt Is Sent

Detection runs on your machine. Personal data is redacted before the prompt is sent.Built for the clinics and law firms where a pasted prompt can carry patient or client data under the GDPR.

Works on the LLM Sites You Already Use

TrustPrompt runs on nine LLM web apps. Alongside the logos shown, it also covers Perplexity, Grok on X, and OpenEvidence — redaction happens in each site's composer before the message is sent.

ChatGPT
Claude
Gemini
Mistral
DeepSeek
Grok

What TrustPrompt Does

Personal Data Is Removed Before It Can Leave the Browser

Two things are always true: your prompt text is analyzed on your own machine, and detected values are replaced with placeholders before the message is sent.

  • Detection Runs on Your Machine

    The detection model and its weights ship inside the extension, the runtime refuses remote model loads, and there is no external cache. There is no detection server to send text to — by construction, not by policy.

  • Redacts Before the Send

    Each detected value is replaced with a typed placeholder such as [FIRST_NAME_1] or [IBAN_2] in the composer, and the same value maps to the same placeholder within a session. The remote model receives placeholders, not the real values.

  • Two Detector Families

    40 checksum-validated regex rules catch structured data such as IBANs, payment cards, and Spanish DNI/NIE, while a 560M-parameter on-device NER model catches names, addresses, and clinical attributes no regex can reliably find.

  • No Telemetry

    There is no analytics or error reporting. The only outbound network call anywhere is the optional enterprise audit webhook, and it carries metadata only — never prompt text or detected values.

  • Minimal Permissions

    The extension requests offscreen, storage, and activeTab only — no tabs, no webRequest, no all-URLs access. It can act only on the nine declared LLM origins, and the placeholder map lives in memory and is discarded when the tab closes.

Detection

A Privacy That Comes From Architecture

PII never leaves the machine for detection is not an operational promise that depends on configuration — it is how the extension is built. Where detection does run, two detectors work together: structured identifiers have a shape a checksum can confirm, while a patient name or a clause naming a counterparty does not — so TrustPrompt uses each method where it is strongest.

No detection backend exists

The model runs in the browser and remote loads are disabled, so there is nothing to send text to for inspection. Hosted AI gateways and proxies, by contrast, must receive the text in order to inspect it.

Nothing crosses a border

There is nothing to host and nothing that leaves the device. After install, detection works fully offline — which removes an entire class of data-processor and cross-border-transfer questions for regulated and public-sector buyers.

The third party never sees the real values

Redaction happens before the LLM receives the prompt, so the values are replaced before they leave the browser. There is no copy of the original text to log, retain, or train on downstream.

Deterministic regex with checksums

Structured data is matched by 40 built-in rules with checksum validation — IBAN (per-country length plus MOD-97-10), payment cards (Luhn), Spanish DNI/NIE/NIF/NUSS, passports, and secrets such as API keys, bearer tokens, and PEM private keys. These are exact and fast.

Transformer NER for the rest

Model finds the unstructured data no regex can catch reliably — names, addresses, organizations, and demographic and clinical attributes. Model exposes 54 entity types across Twelve languages.

One value, counted once

When both detectors fire on the same value — a regex DNI and a model identifier over the same digits — a cross-source dedupe step collapses them, so a value is never double-counted and the preview stays readable.

Local at Interactive Speed

A 560M-Parameter Model Running in the Browser, on Your GPU

Model Runs on Your Hardware

The runtime tries WebGPU with fp16, then WebGPU with q8, then WASM with q8. Backend selection is validated up front, so an incompatible GPU produces an explicit error rather than silently returning zero detections.

Why local is even possible here

Running a 560M-parameter transformer locally, at interactive latency, inside a browser extension is what WebGPU makes practical. Tools that offload detection to a server often do so because they cannot run a model of this class on the client.

Works without a qualifying GPU

The fast path needs a GPU exposing shader-f16 with around 512 MB of max buffer size. On machines without one, the WASM path keeps detection fully local at lower speed — it does not fall back to a server.

What Happens When You Press Send

Each prompt moves through the same sequence in the page, on your machine, before any text reaches the LLM.

Step 1: Block the Native Send

The site's own send is intercepted in the capture phase and held, so nothing leaves the page until detection and redaction have run.

Step 2: Built-In Rules and Your Watchlist

Deterministic, checksum-validated regex patterns run first, gated by the categories you or your administrator enabled, followed by your own custom watchlist terms.

Step 3: On-Device Model Detection

Each chunk of text is classified by the on-device NER model; overlapping detections are merged, aliases collapsed, and each entity is kept only if its score clears the configured threshold.

Step 4: False-Positive Suppression

A tiny on-device classifier, trained only from your own previous preview decisions, suppresses learned false positives. It stays on your machine.

Step 5: Preview

A panel lists what was found. You can dismiss an individual false positive or cancel the send entirely before anything leaves the page.

Step 6: Redact and Re-Send

Detected spans are replaced with typed placeholders, organization regex rules run last in an isolated worker with a timeout, and the redacted text is written back and sent.

Pricing

From a Free Single User to a Centrally Managed Estate

The free tier gives one person local redaction on all nine sites at no cost. Paid plans add shared configuration and your own detection rules for a team; the managed tier adds central policy. SMB prices are per organization, ex-VAT, billed annually.

Individual

One user, fully local

Free
free
  • Local redaction on all nine LLM sites
  • User-owned on/off toggle
  • Personal watchlist of custom terms
  • On-device false-positive learning
  • All seven categories on, fail-closed
most popular

Small Team

Up to 25 users

990
per year+ 21% VAT at checkout
  • Everything in Individual
  • Shared sensitivity settings
  • Custom regex for your own identifiers
  • Employee, ticket, and patient ID rules
  • Simpler rollout than full MDM

Business

Up to 100 users

2900
per year+ 21% VAT at checkout
  • Everything in Small Team
  • Shared configuration across the team
  • Custom organization regex rules
  • Priority support

Growth

Up to 250 users

5900
per year+ 21% VAT at checkout
  • Everything in Business
  • Larger team rollout
  • Onboarding assistance
  • A path to centrally managed policy

FAQs

TrustPrompt — Frequently Asked Questions

Straight answers for the clinics, firms, and teams deciding where their prompt text goes.

Is my prompt text sent anywhere for detection?
No. The detection model and its weights ship inside the extension, the runtime refuses remote model loads, and there is no external cache. Your text is analyzed on your own machine; there is no detection server. After install, detection works fully offline.
Which sites does TrustPrompt work on?
Nine LLM web apps: ChatGPT, Claude, Gemini, Perplexity, Mistral, Grok on grok.com, Grok on X, DeepSeek, and OpenEvidence. The extension can act only on those declared origins.
What does it detect?
Two families together. 40 checksum-validated regex rules catch structured data — IBANs, payment cards, Spanish DNI/NIE/NIF/NUSS, passports, API keys, bearer and JWT tokens, and PEM private keys. A 560M-parameter on-device NER model with 54 entity types catches names, addresses, organizations, and demographic and clinical attributes.
What are the hardware requirements?
A Chromium-based browser (Chrome or Edge) version 124 or newer. The fast path uses a GPU exposing shader-f16 with around 512 MB of max buffer size; without one, the WASM path runs detection locally at lower speed. Budget for a model on the order of 1 GB resident.
Which languages are supported?
The pipeline is multilingual by data and targets twelve languages. Built today: an active English model and three Spanish model variants. Adding a language means shipping a model and its category map, not changing code.
How is it managed across an organization?
IT pushes a managed policy through Windows Group Policy, Microsoft Intune, or Jamf. A valid policy object is itself the entitlement — there is no license server and no activation call. The policy can set which categories are on, per-entity thresholds, fail mode, organization regex rules, an audit webhook, and the model backend.
Does anything get logged?
There is no telemetry, analytics, or error reporting. When an organization enables audit logging, the payload is restricted to metadata — entity-type counts, latency, host, outcome, model id — and never includes prompt text or detected values. The placeholder map stays in memory and is discarded when the tab closes.
What happens if detection fails?
The extension is fail-closed by default. The native send is blocked first; if any stage of detection or redaction throws, the send stays blocked rather than leaking unredacted text. The safe state is the default state.
How much control does the user keep?
The master on/off toggle is user-owned at every tier and cannot be forced on remotely. Users keep a personal watchlist, can dismiss individual false positives in the preview before a send, and can reset the on-device false-positive model at any time.

Keep Personal Data Out of Public LLMs

Tell us about the sites your team uses and the identifiers you need to protect. We will show you how TrustPrompt fits, with detection running on your own machines.