engnotes · legal
Cookie Policy
Last updated: September 25, 2026
The cookies we use, why we use them, and how you can manage your preferences.
What Are Cookies
Cookies are small text files that are placed on your computer or mobile device when you visit a website. They are widely used to make websites work more efficiently, as well as to provide information to the website owners.
How We Use Cookies
Engineering Notes uses cookies for the following purposes:
- Essential functionality: To enable core website features like secure login and cookie consent management
- Analytics: To understand how visitors interact with our website (only with your consent)
- Preferences: To remember your theme choice
Types of Cookies We Use
3.1 Essential Cookies
These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in, or filling in forms.
Essential Cookies
| Cookie Name | Purpose | Duration |
|---|---|---|
| __Secure-authjs.session-token | Keeps you signed in (only set when you sign in) | Up to 30 days |
| authjs.session-token | Same sign-in session under the name older browsers and local development use | Up to 30 days |
| __Secure-authjs.state, __Secure-authjs.pkce.code_verifier | Protect a GitHub, Google or X sign-in while it is in progress | About 15 minutes |
| __Host-authjs.csrf-token | Cross-site request forgery protection for sign-in | Session |
| __Secure-authjs.callback-url | Returns you to the page you were on after signing in | Session |
| cookie-consent | Stores your cookie choice (browser local storage) | Until you clear it |
| visitor-id | Random identifier sent with your cookie choice, as the record of consent (browser local storage, set only when you choose) | Until you clear it |
Features you choose to use store a little more, only when you use them. These are essential for the feature to work:
Feature storage
| Cookie Name | Purpose | Duration |
|---|---|---|
| guest_session_id | Lets a signed-out reader take a quiz and see the result (set when you open a quiz) | 7 days |
| notesensei_session | Keeps a signed-out reader's NoteSensei chat session together (set when you ask a question) | 7 days |
| notesensei_conv_<post> | Reopens your NoteSensei conversation on a post (browser local storage) | Until you clear it |
| quiz_taken_<post> | Remembers that a signed-out reader already took a post's quiz (browser local storage) | Until you clear it |
| engnotes:feedback-client-id, engnotes:article-feedback-vote:<post> | Random identifier and your answer to "Was this article helpful?", so a vote counts once (browser local storage, set when you vote) | Until you clear it |
3.2 Analytics Cookies
These cookies help us understand how visitors interact with our website by collecting and reporting information anonymously. They are only placed with your explicit consent.
Analytics Cookies
| Cookie Name | Purpose | Duration |
|---|---|---|
| ph_phc_MxEYRORy9VGYTbW1Yb8ecB8DZtEdeOKnRNLZrMIM7rF_posthog | PostHog analytics: an anonymous visitor ID and session state (cookie and local storage). The analytics library does not load, and sets nothing, until you accept analytics | 1 year |
| __ph_opt_in_out_phc_MxEYRORy9VGYTbW1Yb8ecB8DZtEdeOKnRNLZrMIM7rF | Records that you accepted analytics (browser local storage, set only after you accept and removed if you withdraw) | Until you clear it |
3.3 Preference Cookies
These remember choices you make yourself, such as a light or dark theme. They are only stored when you make that choice.
Preference Cookies
| Cookie Name | Purpose | Duration |
|---|---|---|
| engnotes-theme | Remembers the light or dark theme you picked (browser local storage, set only when you change the theme) | Until you clear it |
| notesensei_privacy_dismissed | Remembers that you closed the NoteSensei privacy notice | 1 year |
| notesensei_expert_hint_dismissed, explain-hint-used-at, explain-hint-shown | Remember that you dismissed or already saw NoteSensei hints (browser local and session storage) | Until you clear it (explain-hint-shown: this tab only) |
3.4 Marketing Cookies
We do not currently use marketing cookies. If this changes in the future, we will update this policy and obtain your consent before placing any marketing cookies.
Managing Your Cookie Preferences
When you first visit our website, you will see a cookie banner that allows you to:
- Accept All: Enable all categories of cookies
- Reject All: Allow only essential cookies
- Customize: Choose which categories of cookies to allow
You can change your choice at any time. The button below forgets it, stops analytics straight away and shows the banner again. Clearing this site's data in your browser (cookies and local storage) does the same.
Browser Cookie Controls
Most web browsers allow you to control cookies through their settings. Here are links to cookie management instructions for common browsers:
Note: Disabling certain cookies may affect the functionality of this website.
Third-Party Cookies
Some cookies are placed by third-party services that appear on our pages. We use the following third-party services:
- PostHog: For website traffic analysis, hosted in the United States (only with your consent). If you reject analytics, the PostHog library is not loaded and stores nothing. If you withdraw after accepting, its data in your browser is removed.
We do not have control over third-party cookies. Please refer to the respective third-party privacy policies for more information.
Changes to This Policy
We may update this Cookie Policy from time to time to reflect changes in technology, legislation, or our data practices. Any changes will be posted on this page with an updated revision date.
Contact Us
If you have any questions about our use of cookies, please contact us at privacy@engnotes.dev or visit our Contact page.