Cookie policy
Effective: October 23, 2026 · Last updated: October 23, 2026
This policy explains the cookies and similar technologies SixteenKind uses, and how you can control them. It works alongside our privacy policy.
The short version
- We only use cookies that are strictly necessary: to keep you signed in and to protect sign-in from forgery. They are only set when you sign in.
- Your test results are kept in your browser’s local storage, on your device, so you can come back to them. If you sign in, they are also saved to your account (that is covered in our privacy policy, not by cookies).
- We do not use analytics, advertising or social media tracking cookies, so there is no cookie banner to click through. Our usage statistics (Vercel Web Analytics) are cookieless and store nothing on your device.
- Stripe sets its own cookies on its checkout page (on stripe.com) when you buy Pro.
This summary is for convenience. The full text below is what applies.
1. What cookies and browser storage are
Cookies are small text files a website asks your browser to store and send back on later visits. “First-party” cookies are set by the site you are visiting; “third-party” cookies are set by another domain. Cookies can last only until you close your browser (“session” cookies) or for a set time (“persistent” cookies).
Websites can also store information in your browser using local storage (kept until you clear it) and session storage (cleared when you close the tab). Unlike cookies, these are not sent to the website’s server automatically. In this policy, “cookies” includes these similar technologies where relevant.
2. How we use them
We use cookies and storage only to provide features you ask for: staying signed in, signing in safely, and remembering your test progress and results on your device. Each item is described below. The names and durations come directly from how our site is built.
3. Cookies we set
These are first-party cookies on sixteenkind.com, set by our sign-in system (Auth.js). They are set only when you start signing in or are signed in. Browsing and taking tests without an account does not set them. All of them are secure (sent only over HTTPS), cannot be read by page scripts (HttpOnly), and are not used to track you.
| Name | Purpose | Type | Duration |
|---|---|---|---|
| __Secure-authjs.session-token | Keeps you signed in. Contains an encrypted token identifying your account session. May be split into several cookies ending in .0, .1 if large. | Strictly necessary | 30 days from your last visit, or until you sign out |
| __Host-authjs.csrf-token | Protects sign-in and sign-out requests against cross-site request forgery. | Strictly necessary | Session (until you close your browser) |
| __Secure-authjs.callback-url | Remembers which page to return you to after you sign in. | Strictly necessary | Session (until you close your browser) |
| __Secure-authjs.pkce.code_verifier | A one-time security code that makes “Sign in with Google” safe from interception (PKCE). | Strictly necessary | 15 minutes, deleted after sign-in |
4. Browser storage we use
These items are stored in your browser on sixteenkind.com. Browser storage is not sent to our servers automatically. If you are signed in, the site also saves your results to your account so they appear on other devices; see our privacy policy for details. (The older names starting with “archetype” are kept so that results saved before our name changed are not lost.)
| Name | Purpose | Type | Duration |
|---|---|---|---|
| archetype_mbti_user_profile_v1 (local storage) | Saves your test results on this device: your type, preference percentages, cognitive function scores, stress check result, closest type matches, when you completed each test and which tests you have completed. | Functional | Until you clear your browser’s site data |
| archetype_progress_<test name> (session storage) | Saves your answers while you take a test, so refreshing the page does not lose your place. | Functional | Until you finish the test or close the tab |
| archetype_mbti_pro_unlocked_v1 (local storage) | Not set any more. Left over from an older version of the site; we remove it from your browser if we find it. | — | Removed on your next visit |
These items are needed for features you actively use (saving and showing your results), so they are treated as strictly necessary for the service you request. If you block or clear them, the tests still work, but your results will not be remembered on that device.
5. Third-party cookies
Stripe
When you buy SixteenKind Pro, you are taken to a checkout page hosted by Stripe on checkout.stripe.com. Stripe sets its own cookies on its domain, for example to keep your checkout session working and to prevent fraud. We do not load Stripe scripts on our own pages, and we do not control or have access to Stripe’s cookies. See Stripe’s cookie policy.
When you choose “Sign in with Google”, you are taken to Google’s sign-in page, where Google uses its own cookies under Google’s cookie policy. Our pages do not load Google scripts, and our fonts are served from our own domain, not from Google.
Hosting
Our host, Vercel, does not set cookies on our pages for normal visits. If Vercel’s security systems need to check suspicious traffic, they may set a short-lived, strictly necessary security cookie to verify that your browser is genuine.
6. What we do not use
We do not use analytics cookies, advertising or retargeting cookies, social media pixels, or any cookies that track you across other websites. We do not allow third parties to place cookies on our pages.
We do measure, in aggregate, how the site is used with Vercel Web Analytics. It loads a small script from our own domain, sets no cookies and stores nothing in your browser; visits are counted on Vercel’s side using a short-lived code calculated from the request, which is discarded after 24 hours. Our privacy policy explains exactly what it records.
7. Why there is no cookie banner
Privacy laws such as the EU and UK ePrivacy rules require consent for cookies and storage that are not strictly necessary. Everything we use is strictly necessary to provide a feature you have asked for, such as signing in or saving your results, so consent is not required and we do not show a cookie banner. If we ever add non-essential cookies, we will update this policy and ask for your consent first where the law requires it.
8. How to control cookies and storage
You can see, block and delete cookies and site data in your browser settings. Blocking our sign-in cookies will stop you from signing in, and clearing site data will delete results saved on that device. Instructions for common browsers:
Signing out removes the session cookie. To remove only your saved results, clear “site data” or “local storage” for sixteenkind.com.
9. Changes to this policy
We will update this policy if the cookies or storage we use change, and change the “Last updated” date above. See also our privacy policy.
10. Contact us
- SEO Rank SERP LLC
- 8 The Green, Dover, Delaware 19901, USA
- Email: build100k@gmail.com
Related: Terms of service · Privacy policy · Cookie policy · Refund policy · Contact