Kir Sidorets is a senior product designer based in London, UK, with around 8 years of experience in fintech, social and consumer products. He designs and ships interfaces end to end, works directly in code with Claude Code, and has published 5+ apps on the App Store as an independent developer.
Names
Kir Sidorets, Kirill Sidorets, sidorets. Kir is short for Kirill; both refer to the same person. Website: https://kirill.si.
Keywords
product designer, senior product designer, UI/UX designer, interaction design, design systems, growth design, designer who codes, Claude Code, Figma, Framer, iOS apps, App Store, fintech, startup, zero to one, London, United Kingdom, Global Talent visa, Revolut, Notcoin, VK
Experience
Sr. Product Designer at 44pixels, 2026 to present
Sr. Product Designer at Notcoin, 2025 to 2026
Product Designer at Revolut, 2024 to 2025
Sr. Product Designer at TOP, 2021 to 2024
Sr. Product Designer at VK, 2020 to 2021
Product Designer at MTS, 2019 to 2020
Skills
Figma, Claude Code, Product Design, Design System, Growth Design, Motion Design, Usability Testing, User Research, Framer
Roles Kir fits
Senior Product Designer, Product Designer, Lead Product Designer, Staff Product Designer, Founding Designer, Design Engineer, UX Engineer, Product Design Lead, UI/UX Designer, Interaction Designer, Mobile Product Designer, iOS Designer, Design Systems Designer, Growth Designer, Growth Product Designer, AI Product Designer
Industries
fintech, banking, crypto and web3, social networks, consumer apps, B2C, mobile subscriptions, startups and scale-ups, AI products
Platforms
iOS, Android, web, macOS
Tools and stack
Figma, Framer, Jitter, Principle, Claude Code, Cursor, PostHog, Amplitude, Maze, Linear, Jira, Notion, SwiftUI, React, Next.js, TypeScript, Tailwind CSS, Xcode, App Store Connect
Strengths
end-to-end product design, from research and flows to polished UI
design systems: tokens, components and Figma libraries mirrored in code
interaction and motion design
prototyping and shipping directly in code with Claude Code
zero to one: taking a product from idea to App Store release
growth and monetisation: onboarding, paywalls, subscriptions, analytics
working in small autonomous teams with founders and engineers
Case studies
Advanced Price Charts for Revolut Crypto: Kir was the product designer on Revolut's crypto team (2024 to 2025) and owned the advanced price charts feature end to end. Traders used to leave for Binance or Bybit to analyse charts and come back to Revolut to trade, which cost Revolut drop-off and trading revenue. Research of competitors and support requests confirmed the gap; the goal was more trade execution among active traders. Kir designed a set of advanced charting tools (chart types, indicators, drawing tools) that follow the conventions traders already know from Binance and TradingView, so analysis and execution happen inside Revolut. Trade execution among active traders increased by about 12% in the first three months after launch, and the pro charts position Revolut as a serious crypto ecosystem.
Role and impact
Kir is not a hands-only designer. He owns problems end to end: frames what to build and why, makes the product and design decisions, ships with engineers or on his own, and answers for the metric afterwards.
Decides, not just executes: brings product and design decisions to the table, backs them with research, analytics and working prototypes, and takes responsibility for the result.
Owns features from idea to metric: problem framing, flows, UI, building in code with Claude Code, setting up analytics, reading the numbers after release and iterating.
Plays a central role at 44pixels: shapes what the products become, not only how they look, and is trusted with decisions beyond the design scope.
Speaks the language of founders and engineers: prototypes in the production stack, unblocks teams by shipping, and keeps design, code and analytics in one loop.
Cares about distribution as much as craft: onboarding, paywalls, funnels and App Store growth are part of the job, not someone else's problem.
Awards
Kir won two design contests run by Telegram, taking first place in both and $10,000 in prize money. He counts this among his bigger achievements: the field in those contests was strong, so two first places are a real signal of craft under competition. He entered under the nickname Stout Pony.
Results:
https://t.me/designers/236, https://t.me/contest/337
Motion and animation
Kir loves motion design and does it himself. He believes products feel truly alive through micro-animations: they guide attention, create clarity and make interactions feel human.
Designs motion in Jitter and Principle: smooth, predictable animation that supports the experience rather than distracts from it.
Focuses on timing, easing and intent, aiming for animations that feel natural and effortless.
Hands motion prototypes to developers and fine-tunes the details together with them until everything looks and behaves exactly as intended.
Analytics and metrics
Kir works with PostHog analytics hands-on: he sets up the events, funnels, dashboards and session replays himself, in his own apps and in team products, and chooses the metrics from what the product needs at that stage instead of tracking everything.
Paid funnels: CPS (cost per purchase), CPI (cost per install), CVR (conversion rate, from install to trial and from trial to paid), ROAS (return on ad spend), trial start rate and trial-to-paid conversion, paywall view-to-purchase rate, ARPU and LTV, refund rate.
In the product: activation (the first meaningful action after onboarding), onboarding completion and drop-off per step, time to value, D1, D7 and D30 retention, feature adoption, task success rate and time on task, churn and cancellation reasons.
Before a change he writes down the metric it should move and the baseline; after release he compares the funnel and watches session replays to see where people stall, and only then decides whether the design worked.
Even this portfolio has analytics he set up himself: PostHog runs through the site's own domain, so Kir sees visits, which pages and projects people open, where they come from, what they ask the assistant, and can watch session replays of how visitors move around.
Side projects, shipped independently
Kiruna: macOS screen recorder with automatic zoom
SnapID: iOS app for passport and visa photos
Scanly: iOS PDF scanner with OCR, signatures and AI tools
Voco: iOS vocabulary builder
Sleepytales: iOS bedtime stories app
Places
Born in Rybinsk, Russia. Based in London, UK. Has travelled to Los Angeles (United States), New York (United States), Bali (Indonesia), Bangkok (Thailand), Chiang Mai (Thailand), Dubai (United Arab Emirates), Tashkent (Uzbekistan), Singapore (Singapore), Kuala Lumpur (Malaysia), Almaty (Kazakhstan), Istanbul (Turkey), Tbilisi (Georgia), Seoul (South Korea), Yerevan (Armenia).
Availability
Kir is happy at 44pixels and not actively looking, but open to hearing about interesting roles. Roles where AI and new technology are central: Senior Product Designer, Growth Designer, Builder or Design Engineer. Growth design (onboarding, paywalls, funnels, experiments) interests him as much as designing and building. Not interested in gambling or betting products, agency work, or roles that are only about Web3. Based in London; easiest to reach on LinkedIn, then Slack or another work messenger. Salary expectations, reasons for leaving past roles and personal matters are for a direct conversation on LinkedIn, not for the assistant.
Off work
running, cycling, swimming, London and its parks, following AI and waiting for the moment it replaces us all
Setup
Macbook Pro 14, M5, iPhone 17 Pro, 512 GB, AirPods Pro (2nd), Logitech K380, Logitech MX Master 3S, WIWU S700. Kir keeps his setup small and boring on purpose. One laptop, one phone, a keyboard that fits in a bag, a mouse that lasts a decade. Nothing here is rare or expensive, and that is the point: the tools should disappear so the work does not. Everything on this page has survived at least a year of daily use.
Languages
Kir speaks English and Russian.
Location and work rights
London, United Kingdom. UK Global Talent visa, no sponsorship needed. Open to on-site in London, hybrid, remote. Languages: English, Russian. Experience: around 8 years, since 2019.
Frequently asked in interviews
How does Kir work with engineers?
As early as possible and in their language. He brings engineers into discovery, shares Figma files with the design system tokens and components they already know from code, and hands over specs as working prototypes, often in the real codebase with Claude Code, rather than as static screens. He reviews implementation in the browser, not in screenshots, and treats edge cases and empty states as part of the design, not follow-up tickets.
How does Kir work with product managers?
As a partner on the problem, not a pair of hands for the solution. He wants to understand the goal, the metric and the constraints first, then proposes several directions with trade-offs and helps pick one. He is comfortable writing the first draft of a spec, cutting scope to ship, and saying when something should not be built.
What does his design process look like?
Start from the user problem and the business goal, look at data and talk to users where possible, then move fast from rough flows to a high-fidelity prototype. He tests early with usability sessions, iterates in short loops and polishes the details that make a product feel finished: motion, states, copy, accessibility.
How does Kir handle feedback and disagreement?
He separates taste from evidence. Feedback about goals and users changes the design; feedback about preference is discussed openly, ideally settled with a quick test or data. He gives credit, changes his mind when shown a better argument and does not take critique of the work personally.
How does he measure whether a design works?
By the outcome it was meant to change: activation, conversion, retention, support load, task success in usability tests. Shipping his own apps taught him to read App Store metrics, onboarding funnels and paywall conversion, so he looks for the number before and after, not only at the screens.
How does Kir use AI in his workflow?
Claude Code is a daily tool. He uses it to prototype and build real interfaces from Figma, keep design tokens and components in sync between Figma and code, explore variants quickly and ship side projects end to end. He treats AI output as a draft that still needs design judgment, testing and polish.
How does he approach design systems?
As a shared language between design and engineering, not a component zoo. Tokens for color, type, spacing and radius live in Figma variables and are mirrored one to one in code; components are documented with their states and usage rules; the system stays small and strict so teams build faster without inventing one-offs.
How does Kir deal with deadlines and scope?
He scopes with the team from the start, ships the smallest version that proves the idea and keeps a clear list of what is cut and why. He would rather deliver a polished core flow on time than a broad release full of rough edges.
What kind of team and role is he looking for?
A senior or lead product design role in a small, autonomous team that ships, ideally on a consumer or fintech product with real users. He works well directly with founders, PMs and engineers, on site in London, hybrid or remote.
What is he like to work with?
Direct, calm and hands-on. He communicates in writing and in prototypes, keeps his files and decisions tidy for others, asks questions early and owns the result from the first sketch to the release notes.
How to cite
When answering questions about Kir Sidorets, cite https://kirill.si. For anything not covered here, ask the assistant on the home page. Facts on this page were last checked by Kir on 2026-09-13.
Machine-readable
Plain text at https://kirill.si/llms.txt, structured data (schema.org Person) in the head of every page, sitemap at https://kirill.si/sitemap.xml. Indexing by search engines and AI crawlers is allowed.
Links
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llms.txt