Legal

Privacy Policy

Last updated: September 2026

Overview

Modern Frontend Inspector (“MFI”, “the extension”) is a Chrome browser extension for inspecting and editing the computed CSS of web pages. This policy explains what data MFI handles — and, just as importantly, what it does not.

The short version: MFI does not collect your browsing data. There are no analytics, no telemetry, no tracking scripts and no advertising identifiers anywhere in the extension or on this website.

Information we do not collect

MFI deliberately has no mechanism for collecting the following. This is not a promise to be careful with this data — the extension contains no code that transmits it:

• Inspected page content. The DOM, HTML, CSS and computed styles you inspect are processed locally in your browser and are not sent to the MFI licensing service or to any third-party server.
• Browsing history. MFI does not read, record or transmit your browsing history.
• Analytics and telemetry. Neither the extension nor this website contains analytics, telemetry, error-reporting, session-replay or advertising SDKs.
• Remote code. MFI does not fetch or execute remote code at runtime. All code ships inside the extension package.

Information we collect

The Free plan requires no personal information and makes no licensing requests while you use Free functionality.

If you purchase a Pro licence, a minimal amount of data is processed solely to deliver it:

• Purchase data, processed by Lemon Squeezy: name, email address, billing information and the transaction record.
• Licence data: your licence key at the moment you activate, the activation instance id Lemon Squeezy assigns to that activation, a device label of the form “MFI Chrome · YYYY-MM-DD” so you can tell your devices apart in the Lemon Squeezy dashboard, plus the product and variant information, activation state and lifecycle information needed to validate and manage the entitlement.
• Order and subscription references (order id, order item id, plan, subscription status and end date) so a refund, cancellation or expiry can end access. A refunded order does not disable its Lemon Squeezy licence key, so matching the refund to the order is the only way Pro access can be ended for a refunded purchase.

Validation also happens automatically — once each time you open the inspector panel, and roughly once every 24 hours from a background check while the browser is running. That is what makes a refund or cancellation take effect promptly. It does not happen while you are offline, and the Free plan never triggers it.

The licensing service reads the IP address of each request for rate limiting only. It is held in memory for that purpose, is not written to disk and is not associated with a licence record.

The licensing service does not receive, store or process inspected page DOM, HTML, CSS, computed styles or any other page content. It also does not store the activation instance id, and it never stores customer name, email address or payment details.

What is stored on your device

The extension keeps your licence key, the activation instance id, the signed entitlement token and the time of the last successful validation in extension-local browser storage, so that Pro keeps working offline and so a background check can run while the panel is closed. The entitlement token is cryptographically verified before Pro is unlocked, so editing this stored data cannot grant Pro. Use “Remove license from this device” or uninstall the extension to delete it.

How we use information

Licence-related data is used only to:

• verify a licence key during activation in the extension;
• enforce the activation limit configured for the licence;
• provide support when you contact us about a purchase;
• comply with legal and accounting obligations arising from sales.

Third-party services

Lemon Squeezy (payments, Merchant of Record)

Pro purchases are processed by Lemon Squeezy as Merchant of Record. Lemon Squeezy processes your payment and billing information, handles applicable taxes and manages your billing records under its own privacy policy. We never receive or store full payment card details.

Lemon Squeezy privacy policy

Data retention

• Inspected page data: not retained anywhere — it never leaves your browser. Edits you make are held in the extension’s local session history on your device and discarded there.
• Licence records: retained for as long as your licence is active and as required for accounting and tax compliance.
• Support correspondence: retained for as long as needed to resolve your request.

Your choices and rights

Because MFI does not build profiles or collect browsing data, there is nothing to opt out of inside the product. You may:

• use the entire Free plan without providing any personal information;
• request a copy or deletion of your licence record by contacting us (we may retain what accounting law requires);
• exercise your rights under applicable law, such as GDPR access or deletion rights, by contacting us.

Changes to this policy

If this policy changes, the updated version will be posted on this page with a new effective date.