Privacy Policy
What this document is
This policy explains what information Eigenslate collects when you use it, why, who else sees it, and what you can do about it. It covers the graphing calculator, the notebook, and your account.
Five things are worth knowing up front, because they are unusual:
- We use no third-party analytics and no advertising.
- Graphs you save get an unlisted link. Anyone with the link to a graph can view it, but links are not listed publicly anywhere, so others can only see your graphs if you share the link.
- Graph snapshots are permanent. If you create a snapshot of a graph, it remains available even if you delete the graph it came from, or delete your account.
- No one at Eigenslate reads your work unless your account is under investigation or you give permission. § 9 explains when that happens and how you are told.
- Paying for Pro goes through Link, a Stripe service. Your card details never reach us. § 5 lists what Stripe and Link receive.
This summary is here to be read. It is not the legally operative part of the document. The numbered sections below are.
Scope and relationship to other documents
This policy is the canonical statement of what data we collect and why. The Terms of Service govern your use of the service, account eligibility, and the rules for what you may publish. Where this policy and any other document disagree about data handling, this policy governs.
1. Who we are
Eigenslate (“we”, “us”) is the service this policy describes, and the business that provides it is the data controller for the information described here. Our contact details are in § 14.
Operator: Eigenslate LLC, a California limited liability company
2. Information you give us
- Information you provide when you create an account. Your name and email address, your password if you set one, and which version of the Terms of Service and of this policy you accepted, and when. If you sign up or sign in with Google we also receive your Google profile name and profile picture.
- Your work. The graphs and notebook files you save, together with the titles and file and folder names you give them. Unlike graphs, which are unlisted, notebook files are private: they can only be reached while signed in to your account. No one at Eigenslate views the content of your files unless your account is under investigation or you explicitly give us permission; § 9 says when that happens. § 7 says what happens to a graph you have published.
- Your preferences. Your global settings, like editor theme and keyboard shortcuts, and per-document settings like page size and margins.
- Information included in reports. If you send us a report through the report tools in the app, we receive everything you wrote in it, a copy of the file or graph you have open if you choose to include it, and some information about your browser that helps us diagnose bugs. § 8 has the detail.
3. Information we collect automatically
Session information. When you sign in we record your IP address and browser user-agent string and associate it with your session. This is how we keep you signed in. We may also use these records to identify suspicious sign-in activity.
Usage counts. We keep a per-account tally of how many times you performed certain actions including, but not limited to, reading and writing files, publishing graphs, and failed sign-ins. We also record basic facts about those actions, like how much data was written. We use this to enforce rate limits and quotas, to improve the service, and to identify misuse.
Service analytics. We record events about how the service is used, such as a graph or snapshot being read or an account being created. An event records which graph was involved and which account owns it, the country the request came from, and whether it came from a browser or a script. Sign-ups, failed lookups and anonymous reports also record the requesting IP address, which is how we spot automated abuse.
Server logs. Our servers record warnings and errors. These help us find defects.
4. Why we use it
The table below gives each thing we do with your information and why.
| What we do | Why |
|---|---|
| Create and run your account; store and return your work | To provide the service you asked for |
| Send you sign-in codes, password resets and account notices | To let you access and control your account securely |
| Keep session IP and user-agent; count failed sign-ins; CAPTCHA on sign-in and signup | To keep accounts secure and to stop automated abuse |
| Usage counts and service analytics | To keep the service running, to enforce quotas, to detect abuse, and to improve the service |
| Server logs | To find and fix defects |
| Handle a support report you filed, including any copy of your work you chose to attach | To answer the request you made to us |
| Keep a copy of a graph that has been reported to us | To assess the report, and to keep a record of what was reported and what we did |
| Record the IP address of an anonymous report | To stop the reporting system being abused |
| Investigate an account after a report, and keep the record of the investigation (§ 9) | To assess reports, to keep the service safe, and to be able to show what we did and why |
| Take payment for Pro through Link, and keep references to your subscription and the payment events Stripe sends us | To provide the subscription you bought and to keep a record of it |
We do not use your information for advertising, sell it, share it for anyone else's marketing, build a profile of you, or use it to make automated decisions about you. We do not do any of these things for users of any age.
5. Who else sees your information
We use a small number of service providers. This list is complete.
| Provider | What they do | What they see |
|---|---|---|
| Cloudflare | Hosting, database, file storage, network, analytics, logging | Everything stored in or passing through the service |
| Cloudflare Turnstile | The anti-bot check on our sign-in, signup, account and password-reset pages, and on the report forms inside the app | Signals from your browser needed to tell a person from a bot |
| Resend | Sends our transactional email | Your email address and the contents of that email |
| Hosting the mailbox behind our published addresses | Anything you send to one of our published addresses | |
| Stripe and Link | Payment for Pro, if you subscribe: checkout, receipts, renewals, refunds, disputes and tax collection, under Link's terms which you accept at checkout (Terms of Sale § 1) | Your name, email address and the payment details you give them directly at checkout. We never receive your card number. We keep only a reference to your Link customer and subscription and the event records Stripe sends us about them |
Most of these providers act only on our instructions meaning that they handle your information to run the service for us, and for no purpose of their own.
The only exception is our payment provider, Stripe and Link. Stripe and Link decide for themselves what they need for fraud checks, tax and the law, and Link is the seller of record for your subscription (Terms of Sale § 1). What they do with what they hold is governed by their own privacy policies as well as ours.
Email you send us. Messages to our published addresses arrive in a Google Workspace mailbox that we control. Google processes that mail for us, under its data processing terms, and for no purpose of its own.
We load no external fonts, no third-party scripts other than the Turnstile check above, and no content delivery network beyond Cloudflare. We have no advertising partners.
We may also disclose information where the law requires it, or to establish or defend legal claims.
6. Cookies and browser storage
We set no advertising or tracking cookies of any kind, and no first-party code writes cookies for analytics.
Cookies we set:
- A session cookie that keeps you signed in. It is HttpOnly, Secure, and SameSite=Lax, and it holds only a reference to a session record on our servers.
Cookies Cloudflare sets: Cloudflare's bot-management and Turnstile cookies (for example __cf_bm) are set by Cloudflare as part of protecting the service.
Local storage in your browser: the app keeps a working area on your own computer that holds your current editor state, so that the editor is not reset every time you reload the page. This includes, but is not necessarily limited to, which files you have open, a copy of your application settings, the content of files you have not saved anywhere yet, and your undo history. None of it is sent to us, your browser can clear it at any time, all of it is deleted when you sign out with the exception of unsaved documents, and data pertaining to local editing (like undo history for local files).
If your plan includes editing files on your own disk, the app can also create, change and delete files in the folders you have given it access to; those files are never uploaded.
Do Not Track and Global Privacy Control. We do not track you across other sites, we do not sell or share your personal information, and no third party collects information about your activity on Eigenslate over time or across sites. There is therefore nothing for a browser "Do Not Track" or Global Privacy Control signal to switch off. We recognise the Global Privacy Control signal and honour it; because the choice it expresses is already how the service works, honouring it changes nothing. Our machine-readable statement of that support is published at eigenslate.com/.well-known/gpc.json.
7. Graphs, links and permanence
This section describes behaviour that differs from most services. Please read it before you publish a graph.
Saving. A saved graph gets a link containing a long random identifier. Anyone who has that link can view the graph without signing in. We do not publish a list or index of graphs, so a graph can only be viewed by someone you have shared the link with. Anyone who has the link can pass it on without your permission, so treat a graph like a shared document: do not put anything in a graph, including in its title, that would harm you if the link were forwarded.
Deleting. When you delete a graph, we delete it from our servers. A snapshot you made of a graph is not deleted when you delete the graph it came from, and the same applies if you delete your account. This is deliberate: it prevents links referenced elsewhere from breaking over time. The creator of a snapshot is not publicly visible, so a snapshot is not tied to you unless you put identifying information in the graph or its title. We do keep an internal record of which account created each snapshot, including after the account is deleted, so that we can trace problematic snapshots and verify who is asking when a takedown is requested. If a snapshot you created contains information that identifies you and you want it taken down, email privacy@eigenslate.com from the email address on your account, with the link.
Deleting content, or your account as a whole, normally removes it from our servers, with the exceptions in this section and in § 8 and § 9: if someone reports one of your graphs, we keep a copy of the reported graph and a record of the account it came from for as long as the report and any investigation need them, and that record survives deletion of the account.
8. Reports
A report is anything you send us through the report tools in the app, or by email to one of our published addresses (§ 14): a bug report, a feature request, a report from an error screen, a flag on a graph someone else shared, or a complaint about content or an account. Reports are the one part of Eigenslate that can send us a copy of your work at your own request, so this section is worth reading in full. Nothing here happens unless you start it. The other way we can come to see your work, an investigation of your account, is § 9.
8.1 How reports reach us, and whether they are linked to you
Reports differ in whether we know who sent them.
Reports from inside the app (bug reports, feature requests and reports from an error screen) are made while signed in and are linked to your account, so we can reply and show you the status of the report.
Reports from a shared graph page are made by the flag control on the page, which works without an account. From there you can flag the graph as abusive or report a bug. These reports are always anonymous, even if you happen to be signed in: they are not linked to any account, we cannot reply to them, and nothing connects them to you, so we cannot find, correct or delete a submission for you afterwards. We record the reporting device's IP address for these, to stop the reporting system being abused; it is kept in our service analytics for around 90 days, beside the identifier of the graph that was reported (§ 3).
Reports by email carry the address they came from, and we reply there. We keep the email as the record of the report.
8.2 What a report from inside the app carries
Every report includes what you wrote in it and your answers to the questions on the form. It also includes information about the app and your browser: which build of Eigenslate you are running, which part of the app you had open, and basic facts about your browser (user agent, platform, language, window size, display scaling and graphics hardware identifiers). A report from an error screen also carries details of the error itself. This is always sent; it identifies a browser configuration rather than a person.
Optionally, a copy of your work. The form offers to include the file or graph you currently have open, together with the recent warning and error messages your browser recorded, which can quote what you typed. This is the most useful thing we can have when reproducing a problem, so we encourage you to leave it on when the problem is in a file or graph, but you can clear the box before sending and then neither is sent. If the graph you have open was shared with you by someone else, the copy is of that graph.
8.3 Reporting someone else's content
When you report a graph, by the flag on its page or by email, we take our own copy of that graph and keep it as evidence, so that the report can still be assessed if the graph is later changed or deleted. This means that if somebody reports a graph you published, we keep a copy of it. We do not tell you at the time, because notifying the person who was reported would undermine the reporting process. If the report leads to an investigation of your account, you learn of it when that investigation closes (§ 9.2).
You are never told who reported you. Reports and the evidence attached to them are not public and are not shown to the person who was reported. We may have to provide them where the law requires it (§ 5).
8.4 How long reports are kept
Reports fall into two groups, kept for different reasons and for different lengths of time.
Reports about the service are bug reports, feature requests and other requests. We keep them while the problem is being looked into, and for a limited time after it has been resolved, currently about a year, so that we can answer follow-up questions and recognise a problem that comes back. The copy of your work you attached goes sooner: it is deleted once the problem is resolved, or when you delete your account, whichever comes first.
Security reports are an exception among reports about the service. If you tell us on the report form that you are reporting a security problem, we keep the report, the conversation and anything attached to it indefinitely, so that we can show that the report was received and how we addressed it.
Reports about someone else's content are kept indefinitely, together with the copy of the reported graph we took (§ 8.3) and our record of how we assessed it and what we did. That is true whichever way the report was decided. We keep them because, if we are ever asked why we did or did not act on a complaint, the answer has to be shown from what we saw at the time.
Deleting your account does not delete reports you filed. We remove the link between them and your account, but the report text and the conversation remain for the rest of their period, and a report that reached us by email keeps the address it came from. Evidence about someone else's content survives deletion of the graph it came from. If you need a specific report removed, contact us at the address in § 14.
9. When we look at your work
This section is about people, not programs. Storing, serving and backing up your work is automatic. What this section covers is when a person running Eigenslate looks at the content of your notebook files and graphs, which happens in only two situations: with your permission, or under an investigation of your account.
9.1 With your permission
We may ask to look at named files or graphs, and tell you why. This is usually to diagnose a bug or a problem with your account. A plain request leaves your account as it is, and declining costs you nothing.
If we have reason to believe that your account breaks the Terms of Service but cannot confirm it without looking at your work, we may suspend the account until you allow us to look at the files in question. You are told which files; nothing off that list is opened under the request; the suspension lifts by itself once you have allowed everything on it; and if you do not allow it, the account stays suspended until the review is resolved without looking at your work. While an account is suspended we stop collecting payment for any Pro subscription on it, and collection starts again if the account is reinstated. Every permission you give is confirmed back to you in writing, by email and in your inbox.
9.2 Under an investigation
If your account is reported, or flagged by our abuse detection, we may look at your work without asking first. We do this only under a written investigation, meaning that the reason and the evidence are recorded before anything is opened, it is limited in time, and it ends with a written finding.
When the investigation ends, if you were cleared you are told, by email and in your inbox, why you were investigated, what we looked at, and what we found. If you were cleared, the notice says so. If we find that your account breaks the Terms of Service, we take the action the Terms describe (Terms of Service§ 8), usually removing the content or closing the account; an account closed for breaking the rules receives the category of reason and our notice, but not the list of what was examined. We do not look at your work silently the only other case in which you are not told is where the law prevents us from telling you.
9.3 Held copies of investigation materials
We may keep copies of files or graphs that an investigation looked at, after it has closed, so that if the matter comes up again we can show what we saw and why we reached the conclusion we did. A copy is taken while the investigation is open, so deleting the original does not remove it, and you are told which files, by name, at the time. A held copy is opened again only under § 9.1 or § 9.2. Every investigation is recorded permanently: what was opened, why, and what was done. That record survives your account (§ 10, § 12).
Reports you send us are outside these rules: you wrote them for us to read (§ 8).
10. How long we keep things
| What | How long |
|---|---|
| Information about your account, including which version of the Terms you accepted | For as long as your account exists, and 30 days after you delete it. If your account is banned we keep the account record indefinitely |
| Your content (graphs, notebook files etc) | Until you delete the item, and a file or folder you delete from cloud storage sits in the trash for thirty (30) days before it is destroyed; or thirty (30) days after you delete your account, during which you can restore it, see § 12 |
| Published snapshots | Permanently, see § 7 |
| Daily usage counts, and the email send records used for rate limiting | 90 days, then automatically deleted |
| Service analytics events | Approximately 90 days, then deleted by Cloudflare |
| Sign-in sessions | Until they expire or you sign out |
| Server logs (warnings and errors) | At most seven (7) days, then deleted by Cloudflare |
| Reports about the service: what you wrote, the conversation, and your browser details | For a limited time after the problem is resolved, currently about a year, see § 8.4 |
| Security reports, with anything attached to them | Indefinitely, see § 8.4 |
| A copy of your own work attached to a report about the service | Until the problem is resolved, then deleted shortly afterwards, or when you delete your account, see § 8.4 |
| Reports about someone else's content, the copy of the reported graph, and our handling record | Indefinitely, whichever way the report was decided, see § 8.4 |
| Investigation cases, their event log, held copies, and the notices we sent you (§ 9) | Indefinitely; never deleted, and they survive account deletion |
| References to your Link customer and subscription, and the payment event records Stripe sends us | Indefinitely, as the record of what you bought and were charged |
| Email you send to any of our addresses | Indefinitely, for now, in our mailbox |
These are the periods we keep each thing for today. Where we are looking into suspicious activity, we may keep the records that bear on it, such as sign-in sessions, usage counts and analytics events, for longer than the period shown, for as long as that inquiry needs them.
11. Children and younger users
You must be at least 13 to have an Eigenslate account. Eigenslate is built for college-level and advanced secondary mathematics and is not directed at children under 13, and we do not knowingly collect information from them.
We do not ask your age. Instead of gating access, we apply the same privacy-protective settings to everyone: no advertising, no profiling, no tracking across sites, no recommendation feeds, and no collection of anything we do not need to run the service.
If you believe a child under 13 has created an account, contact us at the address in § 14 and we will close the account and delete it and its data (§ 12).
If you are under 18. California law requires us to tell you that you can remove content you posted, and how. You can delete your own graphs and notebook files at any time. A snapshot you published stays available (§ 7) and identifies no one unless you put identifying information in it; to have such a snapshot taken down, email privacy@eigenslate.com from your account email with the link. Removal here does not remove copies other people may have made.
12. Your rights
You can ask us to give you a copy of your information, correct it, delete it, restrict or object to how we use it, or provide it in a portable form. You can also withdraw agreement where we relied on it.
You can delete your account yourself at any time from your account settings; we confirm this by email before acting. Deleting your account closes it at once and starts a thirty (30) day period during which you can restore it by signing in, in case you change your mind or a review of it is already under way. After that, your account record, your notebook files and your graphs are deleted. If you have a subscription, cancel it first; deletion opens when the paid period ends.
Three things survive account deletion: published snapshots remain available so that links to them do not break (§ 7); support reports remain for the rest of their period, and security and abuse reports indefinitely, so that our record of what was reported stays intact, although a copy of your own work attached to a report about the service is deleted (§ 8.4); and investigation records remain (§ 9.3). Reports are disconnected from your account. Snapshots keep an internal record of the account that published them (§ 7), and investigation records keep the email address the case was opened against, so that we can recognise an account that comes back after being closed. This means that, where you published a snapshot or a case was opened on your account, a record that the account existed is kept. If a snapshot's title or contents contain personal information about you, § 7 says what we do about it; if a report does, § 8.4 does.
How we handle a deletion request. Deletion is done from your account settings, and we confirm it by a link sent to your account email before anything happens; that is how we know the request is really yours. If you write to us instead, including through a service that sends requests on your behalf, we will point you to that route, or, if you cannot sign in, send the confirmation link to your account email. We do this because a deletion cannot be undone and we will not carry one out on an unverified request. Whoever asks and however they ask, deleting an account does what § 7, § 8.4 and this section describe and no more: published snapshots and report records stay, disconnected from you, copies of your own work attached to reports go, and investigation records stay as described above.
Two things stop deletion until they are resolved. If you have a live Pro subscription, cancel it first from Manage billing on your account page; deletion is refused while a subscription is active so that you are never billed for an account that no longer exists. And an account that is suspended or closed under the Terms of Service § 8 cannot delete itself while the case stands. The content of an account closed for breaking the rules may be deleted by us once the case is closed.
Your payment data with Link is handled by Stripe. You can ask Stripe to delete it; Stripe cancels any subscription bought through Link, deletes the payment records it holds, and tells us it has done so.
To exercise any other right, contact us at the address in § 14. We will respond within one month.
13. Where your information is held, and how it is protected
Your account, your work and our records are stored in the United States, on Cloudflare's infrastructure, and the service runs on Cloudflare's global network, so requests are handled close to wherever you are. Our other providers (§ 5) are also United States companies.
We protect your information with encryption in transit, hashed passwords, server-side sessions, an anti-bot check on authentication pages, and rate limits on abusable operations.
14. Contact
For anything about your data, whether that is a copy of your information, correction, deletion, objection, a snapshot or report you need taken down, or telling us a child under 13 is using Eigenslate, write to privacy@eigenslate.com.
For copyright takedown notices, write to dmca@eigenslate.com.
To report harmful or infringing content, every shared graph page carries a report flag that works without an account, and you can write to report@eigenslate.com.
For anything else, support@eigenslate.com, or the Report button in the app, which can attach the details that help us diagnose a fault (§ 8).
All four are listed on our contact page, which is linked from the footer of every page of our website.
Postal address: Eigenslate LLC, 11440 W. Bernardo Ct., Suite 300, San Diego, CA 92127, United States
15. Changes to this policy
If we make a material change we will tell account holders before it takes effect, and we will update the version block at the top. We keep a record of every version and its effective date, and we will send you the version that applied on any date if you ask (§ 14).
16. Governing law
This policy is part of your agreement with us under the Terms of Service. The law that governs it is set in the Terms of Service § 18 (Governing law), and a dispute about it follows the Terms of Service § 15 (If we disagree).