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Cookie Policy

Last updated: August 18, 2026

What cookies Sim sets, why, how long they last, and how to change your choice at any time.

This Cookie Policy explains how Sim uses cookies and similar technologies on sim.ai and in the Sim application, what each one does, and the choices you have. It forms part of our Privacy Policy, which describes how we handle personal data more broadly.

If you are in the EU, the UK, or another region where consent is required, we ask before setting anything that is not strictly necessary. You can at any time.

What are cookies?

A cookie is a small text file a site stores on your device so it can recognize your browser on a later request. Cookies are how a site keeps you signed in between pages, remembers a preference, or counts a visit.

  • Session cookies are deleted when you close your browser. Persistent cookies stay until they expire or you delete them.
  • First-party cookies are set by the site you are visiting. Third-party cookies are set by another company whose code the site loads, such as an analytics or advertising provider.

We also use technologies that behave like cookies without being one. Local storage and session storage keep data in your browser rather than sending it with each request; pixels (also called web beacons or tags) are tiny images or scripts that record that a page or email was opened. Where this policy says "cookies", it means all of these.

How we use cookies

We group cookies into the three categories the consent banner offers. Necessary cookies are always on because the service cannot run without them. The other two are off until you turn them on.

  • Necessary — sign-in, session security, abuse prevention, and remembering the choice you made in the consent banner. These do not require consent because the service you asked for cannot be delivered without them.
  • Analytics — how many people use Sim, which pages and features they reach, and where errors happen, so we can improve the product. Measurement only; we do not use these to target advertising.
  • Marketing — measuring which campaigns bring builders to Sim and showing relevant ads on other sites.

Cookies we use

Retention periods are the maximum lifetime set when the cookie is written; a cookie can be cleared sooner at any time. Third-party providers occasionally rename or re-scope their cookies, so treat the provider column as the authoritative reference for anything not set by Sim.

Necessary
CookieProviderPurposeRetention
better-auth.session_tokenSimKeeps you signed in and identifies your session.30 days
better-auth.session_dataSimShort-lived signed cache of your session so each page load does not re-read the database.5 minutes
c15tSim (via c15t)Records the cookie choice you made so the banner is not shown again.365 days
sidebar_collapsedSimRemembers whether the workspace sidebar is collapsed, so the layout does not jump on load.1 year
__cf_bmCloudflareBot-management check on requests to providers we load, such as HubSpot and X.30 minutes
Analytics
CookieProviderPurposeRetention
_gaGoogle AnalyticsDistinguishes one visitor from another.13 months
_ga_*Google AnalyticsHolds the session state for a specific Analytics property.13 months
__hstcHubSpotTracks visits across sessions for the main tracker.6 months
hubspotutkHubSpotIdentifies a visitor across form submissions.6 months
__hsscHubSpotTracks the current session.30 minutes
__hssrcHubSpotDetects whether the visitor restarted their browser.Session
Marketing
CookieProviderPurposeRetention
guest_idX (Twitter)Identifies a browser to the X conversion pixel.13 months
guest_id_adsX (Twitter)Measures conversions from X advertising.13 months
guest_id_marketingX (Twitter)Measures the performance of X marketing campaigns.13 months
personalization_idX (Twitter)Personalizes the ads shown on X.13 months
muc_adsX (Twitter)Measures ad conversions across X domains.13 months
_gcl_*Google AdsAttributes a sign-up to the ad that led to it.90 days

Your choices

Where consent is required, the banner appears on your first visit with accept and reject offered equally, and "Customize" lets you turn each category on or off individually. To revisit that decision later — including withdrawing consent you already gave — . We ask again after 365 days.

Independently of the banner, every major browser lets you block or delete cookies from its privacy settings, and can be set to clear them each time you close it. Blocking necessary cookies will sign you out and prevent parts of Sim from working.

We honor Global Privacy Control (GPC). If your browser or an extension sends a GPC signal, we treat it as an instruction to opt out of analytics and marketing cookies without your having to use the banner.

You can also opt out with the providers directly: Google Analytics, Google Ads, X (Twitter), and HubSpot.

Third-party cookies

Some cookies above are set by companies we work with rather than by Sim. We choose these providers and decide when their code loads, but the data they collect is also governed by their own policies, which we cannot change on your behalf.

The providers currently in use are Google (Analytics, Tag Manager, and Ads), HubSpot, X (Twitter), Ahrefs, and Cloudflare.

Changes to this policy

We update this policy when the cookies we set change, and we revise the "Last updated" date above whenever we do. If a change materially widens what we collect, we will ask for your consent again rather than rely on a choice you made under the previous version.

Contact

Questions about this policy, or about how we use cookies, can go to privacy@sim.ai.