Practical AdTech: Engineering Notes with Code and Examples

In this repository, I will share my notes and code examples on the practical aspects of AdTech engineering. For the past few years, privacy-preserving technologies have been the focus of the industry, I hope this page will help you understand the basic of those technologies with code examples.

AdTech heavily relies on third-party data of users, and the data is often sensitive. In order to protect the privacy of users, the industry has been working on frameworks to keep the data private from being accessed by others but still serving the ads to the users effectively.

Google had been working on a framework called Privacy Sandbox for years, it is a set of technologies that allows advertisers to serve ads to users without collecting user data. However, in late 2025, they decided to phase out some of the technologies in the framework.

As someone who had been working on AdTech for 4 years, I think it is still important to review those technologies and understand them. Google and some W3C working groups have worked on the design / specs to tackle the privacy problems while keeping the industry moving forward!

Getting Started

• Ad Serving — RTB flow, DSP/SSP basics
• Cookies — how cookies enable user identification, with a runnable example
• Frameworks — Privacy Sandbox APIs