Keystone is a web directory built on a simple principle: if a website exists and operates legitimately, it deserves a place in the index. We catalogue sites by category — 22 sections covering healthcare, technology, travel, finance, and more — and list each entry by domain, without commercial ranking or paid placement. The directory was assembled as a reference resource, not a review platform. You will not find star ratings, sponsored results, or recommendation algorithms here. Keystone is closer to a reference shelf than a search engine: organised, factual, and navigable at a glance. Listing your site is free. Submissions are reviewed for basic legitimacy before publication, and accepted sites are indexed under the most appropriate category. The process takes no special knowledge — fill in the form and the entry will be queued for review. We currently index 830 sites across the 22 categories, with new submissions reviewed on a rolling basis. The index spans businesses and resources from dozens of countries, reflecting the genuinely international nature of the open web. Keystone does not sell links, offer sponsored placements, or accept payment for inclusion. The directory is free to browse and free to list in — a reference resource maintained in the public interest of the open internet.