Privacy policy

CoMStudio OÜ, Lõõtsa tn 5, 11415 Tallinn, Estonia, is the data controller for PreviewChecks. You can contact us at support@comstud.io.

This policy applies to PreviewChecks.com, its public check endpoints and the PreviewChecks Chrome extension. It supplements the product-wide CoMStudio privacy and cookie policy, which describes our organisation, service providers and policies that apply across CoMStudio products.

Depending on how you use PreviewChecks, we may process the following categories:

• The URL you submit, its public response, metadata, redirect information and preview image details needed to prepare a diagnostic.
• Standard request, security and performance information, such as IP-related data, browser and device information, timestamps and rate-limit signals.
• Messages and contact details you provide when you contact support.

Do not submit private URLs, credentials, cookies or information you are not entitled to share. PreviewChecks is designed for public pages and links.

When you ask PreviewChecks to inspect a URL, the service fetches the public page and, where needed, its preview image to return a validation report. That report can include social metadata, response information, crawler-like diagnostics, image details and suggested fixes.

PreviewChecks does not require an account and does not maintain a user-facing history of your checks. We apply fair-use limits and security controls to keep the public tool available and to prevent misuse.

After you enable local checks, the extension reads the page URL, title, language, canonical link and social metadata from the rendered document head. It does not read or store page body content, cookies, downloads or browser history.

Local findings stay in session-only extension storage and are removed when the browser session ends. The extension uses that information to show a toolbar badge and a report for the current tab; it does not send the page HTML to PreviewChecks.

A full check is optional. When you choose it, the extension sends the current page URL to the public PreviewChecks API for crawler-like access, image, WAF and TLS diagnostics. That action is initiated only by you.

PreviewChecks uses this data only to provide its disclosed preview-checking features. It does not sell the data, use it for advertising or allow people to read it, except where necessary for support, security or legal obligations. This handling complies with the Chrome Web Store User Data Policy and Limited Use requirements.

We use data to provide the requested diagnostic, maintain and secure PreviewChecks, detect abuse, enforce fair-use limits, respond to support requests and improve the reliability of the service.

In the European Economic Area and the United Kingdom, the legal basis generally is the performance of the service you request, our legitimate interests in operating and protecting the service, or compliance with legal obligations. The applicable basis depends on the context.

CoMStudio uses Cloudflare to deliver and secure PreviewChecks, protect against abuse and apply rate limits. Cloudflare may process standard network, security and performance data for those purposes.

We use essential first-party cookies for service operation and site settings. CoMStudio uses cookieless analytics to understand aggregate service use. PreviewChecks does not use advertising trackers, sell personal data or share personal data for advertising.

For details about providers and processing locations, see the CoMStudio privacy and cookie policy or contact support for the current list of processors.

We retain information only for as long as reasonably needed to provide PreviewChecks, operate rate limits, investigate misuse, meet legal obligations and resolve disputes. Retention can vary by the type of information and purpose.

Data may be processed where CoMStudio or its service providers operate, including outside your country. We use appropriate technical and organisational measures to protect data against unauthorised access, alteration, disclosure or destruction.

Subject to applicable law, you may request access, correction, deletion, restriction, portability or object to processing. You may also withdraw consent where processing is based on consent and complain to a competent data protection authority.

Send requests to support@comstud.io. We may need enough information to verify and process the request. We respond as soon as possible and, where GDPR applies, normally within one month.

We may update this policy when PreviewChecks or applicable law changes. The latest version is published on this page and identified by its update date. Where required, we will provide additional notice or ask for consent.

In this policy, personal data means information that identifies or can reasonably be linked to a person. Processing means any operation performed on personal data. A data controller determines why and how personal data is processed; a processor handles data on the controller's behalf.