Let’s set the stage. You’re in a sprint review for a new product that’s heavy into the development stage, with QA already underway. A feature is basically done, and someone says, “It’s just a small change.” Then you hear the phrase that haunts privacy professionals everywhere:
“We only added a little tracking so we can measure adoption.”
But if you’re not a privacy professional, you might shrug and move on with the meeting.
Fast forward to two weeks after the feature launches, and Sales wants a one-pager for a customer security review. Procurement wants to know which vendors touch the data. Legal asks what your privacy notice says. And Security asks the question that should’ve been asked at the beginning:
“Okay… what data is actually flowing where?”
This is where privacy engineering could have saved the day. Maybe it wouldn’t have blasted onto the scene in leather pants and a shiny hammer. I mean that would be awesome, but I’ll take boring questions asked early by a guy with a dad bod in a polo shirt any day if it means the team doesn’t have to panic later.
Why every product team needs to channel their inner privacy engineer
And most importantly, they’re repeatable. Like quarterly. Like every time a new product ships. Like when a new critical vendor is being onboarded. They become a regular tool in your training toolbox.
When product teams adopt even a little bit of privacy engineering their processes, three things happen almost immediately:
You ship faster because you no longer need late-stage rework, surprise approvals, or emergency privacy policy edits.
You answer customer and auditor questions faster.
You reduce incident blast radius because you have less data, cleaner logs, and hopefully fewer vendors and data retention that’s functioning.
Privacy by design might feel like a lot of work when you just want to build cool things, but I promise you it is not a tax on innovation. If your team can build reliability into a system, you can build privacy into a system. Privacy brings efficiency just like reliability. It’s the same discipline: define requirements, reduce complexity, implement controls, and verify behavior.
So… what is privacy engineering, really?
Simply put, privacy engineering is the practice of turning privacy principles into functional product reality. When I say functional product reality, I’m talking about data fields, database tables, logs, vendor calls, access roles, retention timers, and user choices rather than policies and trainings. We care about how the system actually operates in privacy engineering.
Privacy by design, on the other hand, is the broader operating philosophy that states that privacy shouldn’t be something you add to the product after it’s built. It should be built into the lifecycle of the product with requirements, design, implementation, testing, launch, and ongoing change management.
So, if you can think of privacy engineering a specific application of privacy by design principles.
The foundations of privacy engineering
You can do privacy engineering with fancy frameworks and tooling… or you can do it with a few consistent habits. Either way, the foundations are the same:
Data discovery & mapping: What data do we touch, where does it enter the system, where does it go once it’s in the system, and who can access it?
Purpose & minimization: Why do we need each data element? Could we use less elements to accomplish our goals? Could we use something less sensitive to do the same thing?
User choices & defaults: What choices do users have or need to have to be compliant (consent/opt-out/limit)? Are choices honored everywhere they should be?
Vendor & AI governance: Which third parties touch the data? Are any tools using data to train models or build profiles?
Retention & deletion reality: How long do we keep it? What does delete mean across systems and backups?
Evidence & continuous improvement: How do we prove the above without a scavenger hunt during an incident or audit?
If you’re reading this and thinking, “That’s a lot,” you’re right! But you don’t have to do all of it at once for these principles to be useful to your product design. Ideally, yes. Having a comprehensive system is great, but even a repeatable workflow that makes it hard to accidentally ship privacy debt will send your team in the right direction now.
Basic tips to level up your privacy engineering game without becoming a full-time privacy engineer
Here are practical actions product teams can take today without waiting for a new tool, a new headcount, or a new committee:
Add a “data touchpoints” section to every requirements document where you list the data the feature will collect, generate, infer, or share. If it touches data, it’s in scope.
Make every data element earn its keep. if you can’t explain its necessity in one sentence, you probably don’t need it.
Design with least privilege in mind. Ask who needs access, and how do we prevent default access that’s too broad?
Treat your logs like all your other data. Don’t accidentally log secrets, tokens, identifiers, or full payloads. Also, redact data early, restrict access to logs, and define retention clearly.
Map vendors at the feature level and include what data each vendor receives for each feature.
Bake user choice into processes. If consent, opt-out, or data limitation applies, the system must honor it, including across tags, SDKs, analytics, and vendors.
Design deletion pathways to execute across systems, including vendors and backups. Automation on this front also helps you with your “data attic.” See Your Data is Not a Family Heirloom for more help here.
Create one small evidence artifact per feature. It can be a one-page map, a screenshot of CMP rules, or a short decision log. Future-you will thank you.
Become a paid subscriber to get access to all of the mini tools that we publish with each post. For instance, this post includes a 10-Minute Feature Privacy Map that you can use this week!
Finally, reminder that the opinions expressed in this article are the opinion of The Privacy Design Lab. They are not legal advice, and no attorney-client relationship is formed by reading this article or downloading the 30-Minute Privacy Tabletop Exercise. If you need to consult legal counsel, you can book a consult with ARLA Strategies or other legal counsel you trust!
If you’re tired of privacy advice that only works in theory, you’re in the right place.
The Privacy Design Lab exists for people who want to practice privacy, not just talk about it. It focuses on practical, repeatable ways teams actually learn. We offer hands-on workshops, downloadable systems, and the Privacy Design Lab community where teams and practitioners can go deeper. Paid newsletter subscribers get access to our full archive, plus supporting materials you can actually use.
If that sounds like your kind of work, we’d love to have you.