nuriye sultanTürkçe incele

Senior product designer in Istanbul

I studied industrial product design at Istanbul Technical University and have designed digital products since 2018: conversion for US e-commerce brands, TV and mobile streaming, digital health and now AI-powered travel.

I like problems where behaviour decides the outcome: why someone abandons a checkout, or stops booking therapy after the second session.

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Nuriye Sultan Kostak

Values

What guides my decisions

Understand before designing

Research comes first: the market, the data and what others got wrong. If I don't understand the problem, I can't design for it.

Four things in balance

What users need, what the business needs, what design adds and what the team can build. I weigh them together.

Data and people together

Dashboards show what is happening. People tell me why. I want both before I decide.

The person behind the screen

What they're trying to do, where they get stuck and why they leave.

Better after launch

I ship what solves the problem, measure it, then improve it.

Depth over decoration

Every screen needs a reason. I give flow, structure and words the same care as the visuals.

Ideas the team can build

I design for the real team, budget and timeline, then make it as clear and useful as those limits allow.

Path

From objects to screens

Results

Numbers I can stand behind

~50%more paid sessions after my booking and payment redesignHiDoctor
+55%conversion from eight months of A/B testing, 66% test success rateInvesp
22×return on one CRO initiative: conversion up 42% on desktop, 35% on mobileInvesp

Experience

Where I've worked

  1. Since May 2026

    Hopgogo

    Senior Product Designer · AI-powered travel

    • Sole designer, working with the founders on direction and delivery.
    • Turning an AI itinerary optimisation engine's output into clear, comparable choices.
    • Cut checkout from five steps to four and moved upsells out of payment.
    • Building the design system from scratch in Figma with Tokens Studio.
    • Also designing Zair, an umrah travel brand, end to end, with its own design system.
  2. Oct 2025 - Apr 2026

    Freelance

    Product Designer

    • Redesigned an HR services company's site UX and a US trucking company's site for conversion.
    • Designed and launched ervakiray.com for clinical psychologist Erva Kıray.
    • Designed Tend, my own wellness app concept, end to end.
  3. May 2022 - Oct 2025

    HiDoctor

    UX/UI Design Lead · digital health

    • Led web and mobile product design in a cross-functional squad, from discovery to implementation QA.
    • Managed and mentored a small design team and set up its workflows and reviews.
    • Redesigned the booking and payment flow: about 50% more paid sessions.
    • Built the design system and the Tohumdan Ağaca gamification system.
  4. Jul 2021 - Apr 2022

    Erlab Technology

    UX/UI Designer · OTT, multi-platform

    • Designed streaming experiences across TV, desktop and mobile.
    • Ran user research and usability tests before release.
  5. Oct 2020 - Jul 2021

    Invesp CRO Consulting

    UX/UI Designer · CRO and e-commerce · Chicago, remote

    • Led A/B testing programmes: 66% success rate, +55% conversion in eight months.
    • Ran a pre-holiday CRO strategy: revenue up 17%, 4× ROI in the first week.
    • Fixed 55 conversion bottlenecks in donation flows, lifting conversion 16%.
  6. Jun 2018 - Sep 2020

    Freelance

    Product Designer · e-commerce

    • UX/UI for e-commerce clients, from requirements to implementation.
    • 2019 internships at Arnica (small home appliances), Tasarım Ussu (design office) and Glasst.

Background

Education, training, tools

Education

  • Istanbul Technical UniversityB.A. Industrial Product Design · 2012-2018

Languages

  • TurkishNative
  • EnglishFull professional
  • SpanishBasic

Certificates

  • AI in Product Design master classesInteraction Design Foundation · 2026
  • Mobile User Experience DesignInteraction Design Foundation · 2021
  • Digital Psychology & Behavioral DesignCXL · 2021
  • Conversion Optimization MasteryInvesp Academy · 2021
  • Enterprise Design Thinking PractitionerIBM · 2020

Tools

  • Figma, FigJam, Figma Make, Tokens Studio
  • Claude, ChatGPT, Google Stitch
  • Hotjar, GA4, Microsoft Clarity
  • FigPii, Userpilot
  • Miro, Notion, Jira

Quick answers

In short

What does Nuriye Sultan Kostak do?
A senior product designer in Istanbul. Since May 2026 she's been the sole designer at Hopgogo, an AI-powered travel startup. Before that: three and a half years as UX/UI Design Lead at HiDoctor, a digital health platform.
What does she specialise in?
Behaviour design and gamification, conversion optimisation and A/B testing, design systems and AI-assisted design workflows. Mostly mobile-first B2C products in travel, healthcare and e-commerce.
How does she approach a project?
Research first: desk research and understanding users. She weighs user needs against business goals, design value and technical capacity, and prefers realistic solutions that ship and improve over perfect concepts.
What results has her work delivered?
At HiDoctor, her booking and payment redesign brought about 50% more paid sessions. At Invesp, her A/B testing programmes lifted conversion 55% in eight months, and one CRO initiative returned 22 times its cost.
Where did she study?
Istanbul Technical University, B.A. in Industrial Product Design (2012 to 2018).
How can I contact her?
By email at nuriyesukostak@gmail.com or on LinkedIn.