01
Billing & access flows
I handle the logic around plan changes, custom checkout paths and subscription states.
Nada Sadek
Senior software engineer
Hi, I'm Nada.
I'm a senior software engineer based in Berlin. I work mainly with React, TypeScript, JavaScript and Node.js. I'm particularly interested in billing systems and AI-assisted review interfaces.
I'm open to working with product and engineering teams on a project basis.
Focus
I work best on interfaces where a wrong state is not just a visual bug. It can block access, confuse support, affect billing or make a risky workflow harder to operate.
02
State-heavy products
I build interfaces where a lot is happening on screen at once. I map out application data states carefully to ensure that complex user actions don't trigger accidental API requests, lock people out, or cause confusing support tickets.
03
AI-assisted review UI
I design and build review queues that clearly display confidence scores, show clear visual evidence and handle model errors gracefully.
Work
Prototypes and side projects I built to explore state-heavy workflows, billing risk tooling and human-in-the-loop interfaces.
AI UI QA Inspector
I built this prototype to test how to cleanly separate visual evidence from code data. It parses a screenshot and a DOM snippet simultaneously, drafting clean frontend bug findings that humans can quickly inspect, edit and approve.
Revenue Risk Inbox
I built this review queue to show how incoming customer messages can be automatically parsed into structured, actionable billing and access-risk flags for human review.
Latest Writing
Notes on billing UX, AI review interfaces and frontend systems with real product consequences.
28 May 2026
AI QA Workflow
Frontend
Designing a UI QA Inspector That Separates Screenshot Evidence from DOM Evidence
Lessons from building a UI QA tool that drafts findings from screenshots and DOM snippets.
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20 May 2026
AI Review UI
Frontend
Revenue Risk
Designing a Review Queue for Revenue-Risk Support Messages
How I designed a support message review queue that turns messy billing requests into structured, inspectable risk signals.
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24 Mar 2026
Billing UX
Recovery Logic
Revenue Risk
Why SaaS Billing Systems Still Get Failed Payments Wrong
A breakdown of the flat retry pattern: treating different payment failures the same, then applying one retry and access policy to all of them.
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About
Berlin-based senior software engineer.
I spent the last decade working across SaaS, ad tech and gaming industries. I work mainly with React, TypeScript, JavaScript and Node.js. Frontend-led with backend experience to build API services when needed.
I'm usually drawn to areas with lots of moving parts: billing, internal tools, support workflows and products where business rules, user experience and engineering decisions are closely connected.
I like to work on projects that allow me to take a rough idea and shape it into a product. I enjoy clarifying scope, breaking work down, documenting decisions, aligning people around a plan and leading projects towards release.
I care about collaboration and knowledge sharing. I enjoy working with people from different backgrounds and disciplines and I try to leave projects in a better state than I found them.
Contact
Need senior engineering help on a billing, internal tool or AI review workflow?
I am available for contract work on complex product surfaces, especially billing, subscriptions, internal tools, support workflows and AI-assisted interfaces.
Email: nadafasadek@gmail.com