Narrow learning signals
What can improve your review
- Phrase or dictionary IDs shown
- Whether a phrase was revealed or restored
- Review results and mastery state
- Difficulty and immersion preferences
Privacy by design
We remember your learning—not your browsing.
The product only needs to understand how you interact with language it introduced. It does not need a record of where you went or what you read.
Not part of the learner model
What should not be saved
- URLs or browsing history
- Page titles or search history
- Page text, sentences, or article content
- A profile of which sites you visit
Product principles
Privacy should shape the architecture—not decorate the settings page.
These constraints limit what the product should collect even when more data could make development easier.
Learning events only
Track the smallest interaction needed to schedule review and estimate mastery.
Sensitive-site exclusions
Saffron should pause on financial, medical, authentication, and other sensitive pages.
Local where practical
Keep immediate page processing and reversible browser behavior on the user’s device whenever possible.
Clear user control
Let people reduce immersion, restore text, disable a site, and understand what is being remembered.
The product loop