Privacy Policy

This policy explains, in plain English, what The Lean Stack collects when you use this site, why, and what you can do about it.

Who we are

The Lean Stack is the website at https://the-lean-stack.com. It is run by Emmanuel Kirwa, founder of The Lean Stack, who is the “data controller” for the personal data described here. We handle personal data in line with the UK GDPR and the EU GDPR. To reach us about your data, email hello@the-lean-stack.com or use our contact page.

What we collect

Email signups. If you use one of our sign-up forms, we collect your email address and, optionally, your first name, plus the page you signed up from, the resource you asked for, and any campaign tags in the link that brought you (UTM parameters).
Usage analytics. We record basic events about how the site is used - page views, which links and buttons are clicked, which calculator you used, and which search result you opened (never what you typed into the search box). These events are stored in our own database without your name, email address or IP address. We also use Vercel Web Analytics, which does not use cookies.
Calculator inputs. The numbers you type into a calculator (like estimated traffic or monthly ad spend) may be recorded with the result to help us understand how the tools are used. If you also sign up for our emails from a calculator, the record may be linked to your signup. We don't ask for or need any personal financial account details to run a calculator.
Affiliate and outbound clicks. When you click an affiliate link or a provider link, we record the page you were on, the referring address, campaign tags and your browser's user-agent text. We do not store your IP address with it.
Invoice, quotation and receipt tools, and the image resizer. These tools run entirely in your browser. What you type into a document, your logo, and any image you resize are not sent to our servers. Your business details and logo are kept in your browser tab's session storage so they carry across the document tools, and are removed when you close the tab or press Clear form. If you choose to save a draft, the text is kept in your browser's own storage on your device, not on our servers. We record anonymous usage events (for example, that the tool was used), never the contents.
Technical data. Like any website, our hosting provider handles your IP address and browser details to deliver pages and keep the site secure. We also use your IP address briefly in memory to limit abusive request rates; it is not saved to our database.

We intentionally avoid collecting anything beyond this. No passwords, no payment details, no government IDs.

Cookies, advertising and your consent

We use your browser's local storage for a few things the site needs to work, and we use cookies and similar technologies for advertising only if you allow them.

Stored on your device by us (no consent needed): your light or dark theme choice, your cookie choice, and the draft or session data of the document tools described above.
Google AdSense (advertising). We use Google AdSense to show ads. Google and its partners may use cookies, device identifiers and similar technologies to serve and measure ads and to prevent fraud. Google receives data such as your IP address and information about the pages you view. If you are in the UK, the EU or the wider European Economic Area, AdSense does not load until you click Accept in our cookie banner. We estimate your region from your device's time zone, so we may occasionally show or skip the banner wrongly; you can always change your choice.
Google Ads measurement (optional). Where we run it, a Google Ads tag measures whether our ads lead to sign-ups. It loads only if you click Accept, in every region.

If you reject, or do not answer, these tools do not load. You can change your choice at any time with “Cookie settings” in the footer; if you withdraw consent, the page reloads so the ad scripts stop. Withdrawing does not affect anything done before. You can also manage ad personalisation in your Google ad settings, and learn how Google uses data from sites that use its services at policies.google.com/technologies/partner-sites. Our banner is our own and is not a Google-certified consent platform.

Why we use your data, and our legal basis

Sending you what you asked for and related emails (email address, name): your consent, which you give by signing up and can withdraw by unsubscribing; and, for related emails to people who have signed up, our legitimate interest in keeping you informed.
Running and improving the site (anonymous analytics, calculator data): our legitimate interest in understanding which pages and tools are useful and fixing what is not. You can object to this (see your rights).
Security and abuse prevention (IP address handling, rate limiting): our legitimate interest in keeping the site working.
Advertising and ad measurement (cookies and similar technologies via Google): your consent, where the law requires it.

These bases are the ones that apply under the UK GDPR and the EU GDPR. Where neither applies to you, we rely on the same purposes under the local law that does.

We don't sell your email address or other personal information. We share data only with the providers that help us run the site, each acting on our instructions or under their own terms:

Vercel - website hosting and Web Analytics.
Neon - database hosting for signups, analytics events and calculator records.
Resend - sending and receiving the emails and resources you sign up for.
Google - AdSense and, where used, Google Ads measurement, as described above.

Some of these providers are based in, or process data in, countries outside the UK and the EEA, including the United States. Where that happens, we rely on the safeguards those providers offer, such as the UK and EU standard contractual clauses or approved data-transfer frameworks. We may also disclose information if the law requires it.

Affiliate links and third-party sites

When you click an affiliate link (for example, a “Try Systeme.io Free” button), you're taken to that company's website, which may set its own cookies or tracking to attribute the referral to us. That tracking is controlled by the destination site, not by us, and is covered by their own privacy policy. See our affiliate disclosure for more on how these links work.

How long we keep it

We keep personal data only as long as we need it for the purposes above. Email addresses are kept until you unsubscribe or ask us to delete them. We have not set a fixed deletion period for anonymous usage events and calculator records; if you believe a record relates to you, tell us and we will look for it and delete it where we can.

Your rights

Depending on where you live, you may have the right to: ask for a copy of the personal data we hold about you; have it corrected or deleted; restrict or object to how we use it; receive it in a portable format; and withdraw consent at any time (unsubscribe from emails, or use Cookie settings). If you are in California or another US state with a privacy law, you may also have the right to opt out of targeted advertising and to know what we hold; rejecting advertising cookies in the banner does this on this site.

To use any of these rights, email hello@the-lean-stack.com. We may need to confirm who you are first. We will reply within one month. If you are not happy with our answer, you can complain to your data protection authority, for example the UK Information Commissioner's Office (ico.org.uk) or your national authority in the EU.

Children

This site is aimed at people running or starting a business. It is not intended for anyone under 16, and we do not knowingly collect their personal data. If you think a child has given us their data, email us and we will delete it.

Security

We use reputable hosting and database providers and limit what we collect. No system is perfectly secure, so we cannot guarantee the security of data sent over the internet.

Changes to this policy

If this policy changes in a meaningful way, we'll update the date at the top of this page and, where the change affects your choices, ask again. Continued use of the site after a change means you accept the updated policy.

Questions? Contact us. See also our terms of service.