Make your privacy claims checkable
Turn "we never see your data" from a promise into something your customers can verify. I help you build the proof, with confidential computing and attestation.
Book a 30-minute callYour customers have to take your word for it
Sooner or later a customer's security team or an auditor asks how they can check that promise. What most teams can show them are statements about the system:
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Policies say what you intend
A privacy policy describes how you mean to handle data. It can't show what happened to a specific request.
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Audits check your process
An audit confirms you have the right controls at one point in time. It doesn't show what the code running today does with the data.
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Questionnaires are self-reported
You write the answers. Your customer still has to believe them.
None of these is evidence from the system itself. That’s the gap I help close.
Usually that means confidential computing: the sensitive part of your system runs in a Trusted Execution Environment (TEE), hardware that can produce evidence of exactly which code handled the data.
That evidence is only useful if someone outside your company can check it. So I also build the parts around it: reproducible builds, a transparency log and a verifier your customers can run.
I've built this before
From 2024 to 2025 I worked with Confident Security on OpenPCC, an open-source toolkit for building verifiably private systems. Its client only sends a request to a service after verifying what’s running there.
I wrote about the design in Dear HTTP service, how can I trust you not to break my heart?
Since then I’ve been working on Verbond, which shows where data can go before third-party code runs.
Before all this I spent about 14 years as a backend engineer, mostly in Go, including internal tooling at Zalando. See my resume.
Three ways to work together
Verifiability assessment
A good first step when you're not sure what's possible yet.
Covers
- What you claim about data handling, and who you have to prove it to
- What you can prove today, and the gaps
- A sketch of the threat model
- Your options, with and without Verbond
You get
A written report with the gaps and your options, and a 90-minute call where we go through it with your team.
Price
€4,800 fixed
Five days
Make-it-verifiable sprint
When you know what to prove. New infrastructure is hard to estimate, so I bill by the day, up to a total we agree on up front.
Covers
- One service that handles requests without keeping state
- One cloud and one TEE type
- Built together with your team
You get
Attestation running for that service, and a verification flow someone outside your company can run, with documentation.
Price
€1,200 a day, with an agreed cap
Two or three days per week, for up to eight weeks
Verification retainer
For keeping your claims true while the system changes.
Covers
- Architecture and threat-model reviews
- Answers to attestation questions
- Release checks
You get
Written feedback on each review and release check, and answers to your questions as they come up.
Price
€2,200 a month
Two days a month, three months minimum
Where Verbond fits
I’m also building Verbond. It’s most useful when:
- Your system runs third-party code on your users’ data.
- You want to see where that data could go before that code runs.
If Verbond fits, I’ll say so. I’ll also show you how to get there without it, including doing nothing, so the choice is yours. None of the offers above require it.
And because I have a stake, I won’t be the independent evaluator or auditor for a system that runs Verbond: that should be someone without one.
Let's start with a call
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1
A 30-minute call. You tell me what your system claims and who's asking you to prove it. I'll tell you whether I can help, and if I can't, who might.
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2
A short proposal. Scope, price and dates, if it fits.
Q&A
Where are you based?
In Germany. I work remotely, in English or Dutch. Prices are in euros and exclude VAT where it applies.
Do you still take on Go work?
Yes, Go backend work, especially where privacy matters. Book the same call.
Other questions?
Email me at w@willem.dev.