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Trace Lab · Your data

Privacy, in plain language.

Trace Lab is operated by Thoughtstage LLC. It works without an account and does not ask you for your name or email address. It stores a small amount of anonymous practice data so your progress can survive a refresh and sync when you are online.

Last updated: August 14, 2026

What stays on this device

Trace Lab uses your browser’s local storage for:

  • a cached copy of your challenge progress;
  • completion events waiting to sync while you are offline; and
  • a legacy list of completed challenges used during upgrades.

The installable app also caches its interface and assets so it can open with a weak or missing connection. That offline cache contains application files, not your synced practice record.

What syncs to Trace Lab

When you complete an example, Trace Lab sends a completion event containing the challenge identifier, example number, completion time, and your local calendar date. It does not send code or the individual choices you made while working through the visual trace.

The synced progress record includes:

  • completed challenges and examples;
  • attempt and review counts;
  • first and most recent completion times;
  • practice dates; and
  • the next suggested review date.

How the anonymous identifier works

The browser receives a random identifier in an HTTP-only cookie named trace_lab_anon_v1. The cookie is restricted to Trace Lab, uses SameSite=Strict, and is set for up to one year. On secure connections it is also markedSecure. Trace Lab hashes that random identifier and stores only the resulting profile identifier with the progress records.

There is no cross-device account. A different browser or device receives a different anonymous profile.

Service operation

Like other hosted web apps, Trace Lab’s hosting infrastructure may process ordinary technical request data—such as IP address, browser information, request time, and error or security details—to deliver and protect the service. Infrastructure logging and retention are controlled by the hosting platform.

Trace Lab’s application code does not include advertising or third-party marketing trackers. The hosting, content delivery, and database services necessarily process requests or store the anonymous progress described above to operate the app.

Retention and your choices

Synced progress is retained so Trace Lab can restore your practice history. You can remove the records tied to this browser using the control below. Clearing browser data by itself removes the local copy and anonymous cookie, but it does not tell the server to delete the synced copy.

If you want both copies removed, use Trace Lab’s delete control before clearing this site’s browser data. Without the anonymous cookie, this browser can no longer identify its earlier synced record.

Delete this browser’s progress

This clears Trace Lab progress from local storage, deletes the synced completion and practice records connected to this browser’s anonymous identifier, and expires that identifier cookie. Other browsers have separate anonymous profiles and are not affected.

Questions about your privacy

For a privacy question or request that is not covered by the deletion control above, email Thoughtstage LLC at support@thoughtstage.ai. Please do not include passwords, government identifiers, or other sensitive information.

For installation or practice help, visit the Trace Lab support page.

Changes to this notice

If Trace Lab’s data practices change, this page and its “Last updated” date will be revised to describe the current behavior.

Trace Lab · Operated by Thoughtstage LLC