
OpenSlot for Outlook is for anyone who types "how about Tuesday at 3?" for a living. Pick the people, the timezone, and the date window; it reads Microsoft 365 free/busy (read-only, nothing stored) and returns one clean, paste-ready list of every slot everyone is free, formatted to drop into an email, chat, or document. Use it on the web or inside Outlook: in a new message the list inserts at your cursor, and on a received email "Reply with times" opens a reply with your availability already in it. It respects working hours, minimum slot length, and weekends, and your settings roam between the web app and the add-in. Every account starts with 14 days of Pro with no card, and a free plan continues after that; Pro and Team plans cover individuals and companies. Available in the Microsoft Marketplace and directly inside Outlook's add-in store.
Mathproven is a set of single-purpose paperwork tools for people who do the same calculation every month and need it to be right: construction subcontractors, medical billers, property managers, law firms, insurance agencies, bookkeepers, online sellers, nonprofits, truckers, and people working out crypto gains. Every tool runs entirely in your browser: a file you open is read on your own device and is never uploaded, and the medical billing pages cannot make a network request at all and keep working offline. Every result comes with a certificate, the list of arithmetic checks it passed, such as "line items add up to the total" or "opening balance plus activity equals closing balance"; a result that fails a check is marked not verified and is never presented as correct. Free to use for three runs a month per tool; paid plans remove the limit. Free Excel templates need no account. The tools calculate and check; they do not give legal, tax, or medical advice.
OpenSlot LLC is a Kentucky software company founded in 2026. It makes OpenSlot, a web app and Outlook add-in that turns Microsoft 365 free/busy into a paste-ready list of the meeting times when everyone is free, so people can schedule by email without booking links. OpenSlot reads calendars read-only and stores no calendar data.