Privacy policy
Last updated: October 11, 2026.
Mathproven is operated by OpenSlot LLC. This policy says what we collect, what we never see, and who else is involved.
Your files never leave your browser
When you open a file or type numbers into a tool, the work happens in your browser on your device. The file is not uploaded, and nothing read from it (names, amounts, account numbers, header text) is sent to us or anyone else. There is no upload feature on this site.
The medical billing pages go further: they are served with a security policy that blocks the page from making any network request, they carry no analytics or third-party scripts, and they keep working offline once loaded.
Drafts and settings some tools remember are kept in your browser's own storage on your device. Clearing your browser data removes them.
Spreadsheet add-ins
The Excel add-ins run inside Excel. The Google Sheets add-ons do their reading and math in the sidebar, in your browser: a file you pick is read there, and the results are written into your spreadsheet through Google's script service. Nothing is sent to us.
Either way, the results are stored wherever your workbook is stored: on your device, with Microsoft (Excel on the web, AutoSave, or OneDrive), or with Google. They are stored there, never by us.
The results can hold everything an add-in read. The add-ins that open an 835 file write patient names, claim numbers, payer and payee IDs, and every amount from that file into your workbook, so the company that stores your workbook stores those too.
The Excel add-ins load Microsoft's Office library from Microsoft, as every Excel add-in must, and Microsoft and Google handle your workbook under their own terms. A paid add-in is unlocked by a key you paste in, which the add-in checks on your device without contacting us.
What we store
- Your email address, if you create an account, to sign you in.
- Your plan (free, Pro, or Firm).
- Usage counts, such as whether a refund has been issued on the account.
That is the whole account record. We do not keep passwords (sign-in is by one-time email link), payment card numbers, or any content from your files.
Format requests
If you ask us to support a file format, we receive only the tool you chose and the bank, payer, or software name you typed. Do not type personal information there.
Measurement
We keep aggregate counts: how many times pages in a section were served in a day, and how many accounts were created. Each count carries the section and a channel word, and nothing about the visitor.
The channel word is one of search, marketplace, footer, template, or direct. It is worked out from the link you followed or from the name of the site you came from. The referring address itself is not kept.
When someone subscribes, the section and channel words are also attached to the subscription record that Stripe holds, so we can see which sections subscriptions come from. That record is tied to the subscriber's account, so there the two words are not anonymous.
We do not use advertising trackers, session recording, or fingerprinting. Medical billing pages have no measurement code of any kind and are left out of our own page counts.
To limit abuse of the sign-in form, the number of sign-in links requested for an email address and from a network address is counted for one hour and then discarded.
Cookies
One cookie keeps you signed in. It is set only after you sign in and is not used for tracking.
Who else is involved
- Stripe processes payments and holds your billing details under its own privacy policy.
- Cloudflare hosts the site and sees standard request data such as IP addresses as part of delivering pages.
- Our email provider delivers sign-in links to the address you give. Receipts are sent by Stripe.
We do not sell personal information.
Keeping and deleting
We keep your account record while your account exists. Email [email protected] from the account's address to have it deleted. Stripe keeps payment records as the law requires.
Support
We never ask for your files, and we ask that you never send them. Any file that arrives by email is deleted without being opened, and a message that looks like it contains file contents is deleted unread.
Other messages sent to [email protected] are kept for up to 30 days. An automated system on our own computer reads them to pick an answer from this site's published help text.
Changes
If this policy changes, the new version is posted here with a new date.