Sidney Dolak
ENCZ
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Product engineer · Fintech · Mobile apps & digital products

Design, Buildand LaunchDigital Products

I'm a product engineer. My experience and expertise are in financial technology and other regulated environments. I can take on the entire development process: from the initial analysis through design and the build itself to release.

Zdeněk Dolák, known professionally as Sidney Dolak.
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01 Case studies

From MVP to production.

Selected builds: mobile apps in regulated fintech and healthcare, plus the KYC and onboarding flows, payments, and web surfaces around them. Each opens into the problem, the constraints, and what I shipped.

01Anonymous Czech IT companyThe month's result on a phone, from an MIS warehouse that has no API.HealthcareMIS app
02KYB in one screen: a company number in, a source-stamped AML report out, with the checks resolving live.MoniveroKYB
03Anonymous UK companyThe merchant app for a UK FCA-authorised acquirer, from onboarding through daily payments management.Merchantpayments
04Anonymous UK companyRegulated onboarding that reads like a consumer sign-up: identity verification and e-signature, in the app.KYConboarding
View all case studies

02 Services

What I build for product teams.

  • Cross-platform mobile apps

    iOS and Android from one codebase, MVP to production: consumer apps, B2B tools, and regulated products that have to work every day. TypeScript throughout.

  • Digital products, design to launch

    The whole product, not one screen: first analysis, flow and interface design, the mobile and web sides, and onboarding people actually finish. From brief to release and the first real users.

  • Payments & fintech integration

    Integrating payment gateways and fintech APIs cleanly: API workflows, integration, and onboarding.

  • Product engineering & consulting

    I join your team to own a product surface end to end, or advise on a mobile or payments build, from architecture to shipped code.

Companies I’ve worked with

Employers, clients and my own ventures, 2021 to today.

  • GoPay
  • Fonco
  • Monivero
  • Tolaron
  • AtletiLabs
03 About

I’m Zdeněk Dolák, known professionally as Sidney Dolak: a product engineer who has spent 8+ years building digital products in TypeScript, from first analysis through design to release, most often for fintech and other regulated environments.

More about Zdeněk Dolák
  • Cross-platform mobile
  • TypeScript
  • iOS & Android
  • Next.js
  • Node.js
  • Payments & KYC/AML
04 Why me

Why work with me?

Work with me
Two plain phone outlines side by side, threaded by one unbroken line: one codebase, both platforms.
A single outlined payment card carrying a contactless symbol.

Onboarding UX that converts

Case study
8+ yrsshipping software
sidneydolak
MVP → productionmobile lead, regulated fintech
sidneydolak
iOS · Android · WebCross-platform · Next.js
Insured and dependable

Payments and compliance, first-hand

I've worked inside an FCA-authorised acquirer and a payment gateway, so I know what KYC/AML, PCI, and audit trails ask of a product. When a build needs deeper regulatory sign-off, I bring in trusted specialists.

KYC blog
Tolaron
Bigger scope

Need more than one engineer? For larger fintech builds — full teams, longer timelines, delivery at scale — I work through Tolaron, a Prague venture studio.

Contact Tolaron
05 KYC Blog

KYC Notes

Notes on KYC, onboarding, and AML in regulated fintech, where product, engineering, and compliance meet in practice. Practical, opinionated, and grounded in shipped work.

Read the KYC blog
A single green shield with a check mark, a faint arc of EU stars curving behind it, on a dark forest ground.AML/CFT8 min readOutsourcing Customer Due Diligence: Why It Should Be the Default Choice for EU Obliged EntitiesFrom July 2027, the AMLR makes outsourcing customer due diligence an explicit, regulated option. Why it should be the default, not the fallback.
A single lit guardrail curving away into the dark, holding the line of a road that is otherwise empty.AI & vibe coding7 min readGuardrails, not brakesAI vibe coding and regulated fintech look like opposites: speed versus evidence. They are not. How to ship fast and still hand an auditor a clean trail.
06 FAQ

Questions, answered up front.

How do we get started?

With a short intro call. You tell me what you're building and where you need help; I'll be honest about whether I'm the right fit and how I'd approach it. If it's a match, I scope the work before anything begins.

How do you charge?

Time-based (day or sprint rate) for ongoing product work, or a fixed price for a clearly defined scope. Estimates are transparent and I flag risks early, so there are no surprises on the invoice.

Do you work remotely?

Yes. I'm based in the Czech Republic and work remotely and solo. I don't have a team in Europe or the UK. In the UK I worked on contract, leading mobile remotely for years. Your process, your stack, your timezone.

What do you work on?

Mobile-first product engineering: cross-platform apps for iOS and Android, onboarding and activation flows, and the web surfaces around them. I bring deep payments and fintech experience, including KYC/AML and payment-gateway integrations. Cross-platform mobile, TypeScript, Next.js, Node.js.

Can you join an existing team?

Yes, that works too. What I prefer is custom development where I take over the whole mobile app product and own it end to end. Either way: senior ownership, low overhead, no long onboarding.

Is working with you low-risk?

I ship reviewed production code, keep a clear trail of decisions, and carry professional liability insurance for IT services, so an engagement starts on solid footing.

Still have a question? The first call is free, with no commitment.

Book a 15-minute call