Terms of Use

Last updated: 2026-05-19

By using a7t.ai, booking a consultancy session, or buying a booklet, you agree to these terms.

The consultancy session

  • A session is 45 minutes, conducted over video (link sent by Cal.com).
  • Prices and currencies are set on the Cal.com booking page for each session.
  • Payment is collected by Cal.com at the time of booking.
  • Reschedule: allowed up to 1 business day before the call, and only once per booking. Use the link in your Cal.com confirmation email.
  • Cancellation / refund: allowed up to 1 business day before the call for a full refund. After that the session is non-refundable.
  • After the session, I may follow up with a written summary or, if you discussed a custom project, a proposal. Sending a proposal does not commit either party.

Digital products (booklets)

By placing an order for a digital booklet you agree to the following.

  • What you receive. A PDF file at the version current at time of purchase. You receive all future updates to the same title at no additional cost, by email.
  • License. Personal-use, non-transferable. You may not resell, redistribute, or strip the file’s metadata. You may quote excerpts with attribution.
  • Delivery. The download link is sent by email immediately after payment, via Polar’s customer portal. The link remains active in your Polar account indefinitely.
  • Pricing. All prices are shown in EUR and include any applicable tax. Polar.sh acts as the merchant of record and handles EU VAT; Polar’s own Buyer Terms apply to the payment transaction itself and are linked from their checkout page.

Refunds: 14 days, no questions

We offer a 14-day, no-questions refund on every booklet, even after you’ve downloaded it. If within 14 days of purchase you decide the booklet isn’t what you needed, reply to your purchase confirmation email and we will issue a full refund through Polar. Refunds typically land in your account within 5 business days.

After 14 days the purchase is final, but you can still ask: where the booklet fell short, we may issue a goodwill refund or credit at our discretion.

Scope of advice

The consultancy is an exchange of ideas and recommendations between practitioners. It is not professional legal, financial, or medical advice. Recommendations are made in good faith based on the information you provide. The same applies to written content in articles or booklets: it reflects working-engineer experience, not formal advice.

Intellectual property

  • Open-source projects on this site are licensed individually. See each repo for its license.
  • Articles, diagrams, illustrations, and the text of paid booklets are © Leonardo Cardoso unless noted. You may quote excerpts with attribution. Wholesale reuse requires written permission. The personal-use license for paid booklets is described in the “Digital products” section above.

Limitation of liability

a7t.ai and Leonardo Cardoso are not liable for indirect or consequential damages arising from use of the site, the consultancy, or the booklets.

Contact

Leonardo Cardoso · [email protected]