NOT ONE THING. ONE THING AT A TIME.
One craft at a time, twenty years running. Currently: design systems built for people first — accessible enough that AI agents read them too.
Beyond the iPhone, on a system built for everyone
Swappie is Europe's leading refurbished-electronics platform. Alongside my product-team work I've functioned as its principal-level designer, across three strands at once: taking the store beyond the iPhone, turning the European Accessibility Act into a standard every team follows, and rebuilding the design system so people and AI agents ship from the same source.
Taking Swappie beyond the iPhone
MacBook launch
Owned the epic with product and engineering. Usability tests showed people pick a MacBook by type and use, not specs, so the category opens with use-case groups. Live in three markets since June 2026.
AirPods
Card sorts settled one product page per family, with the charging case as a configuration.
Trade-in and accessories
Moved trade-in to where people decide, in the cart and category pages, and grouped accessories after add-to-cart. My accessory research led to the country price test.
A homepage for many categories
Tree tests chose the structure; the category grid won its A/B/C test with a near-significant uplift in B2C conversion and rolled out to everyone.
Accessibility as a shared standard, built into the system
EAA / WCAG 2.2 AA compliance program
Audited 26 views across the full purchase, sell, and account flows — keyboard, screen reader, 200% zoom, and automated testing — then built an 11-topic prioritized remediation roadmap and aligned the compliance position with legal ahead of the EAA's June 2025 in-force date. Delivered a company-wide training covering engineering, legal, and marketing.
AI-agent design infrastructure
Built the pipeline connecting design-system tokens straight to generated code, so AI agents read and edit against the live system — now used across multiple product launches. Design changes now ship as reviewed, agent-authored pull requests, with zero incidents across the rollout. Co-winner of the company AI Wizard contest (Dec 2025).
Design system rebuilt as the vehicle for both
Rather than retrofitting fixes, used the compliance deadline as the occasion to rebuild the Swappie Design System on a modern accessible foundation and drove its migration into Storybook — moving it from Figma-only to a system that exists in code.
Trade-in forms
Lighthouse accessibility, category page
Accessory attach rate
How the work moved through people
Design strategy workshop
Facilitated the first cross-team strategy session for all of Swappie's designers. The group voted three principles: design as a strategic function, design-led sprints, whole-journey mapping.
Accessibility training
Ran company training for Engineering, Marketing and Legal, co-presented with an engineer.
Mentoring
Mentored a brand designer until they handed over production design-system cards almost independently.
Research and delivery with the team
Ran tree tests and card sorts with a fellow designer, and wrote specs clear enough that a test launched early.
“The drift between what was designed and what gets delivered is a real thing, and it has become narrower thanks to your work.”
“Jukka's clear guidance and great collaboration skills provided me with enough clarity […] This led to us launching the test ahead of time.”
Designing products and the system that scaled them
Zenniz had launched with agency-defined brand tokens and apps built for what existed, not what could come next. As UX Lead, I built a design system first, then used it to launch new products and audit existing ones — so the suite could grow without rebuilding.
Scalable design system
I built a centralized component library that became the source of truth — ensuring every product, new and old, spoke the same visual and interaction language.
New product design
As the product suite expanded, new apps needed to feel like part of the same family — not add-ons. Working within the established design system, I designed new apps that extended the suite without requiring users to relearn anything.
UX audit & optimisation
Tennis technology operates in demanding conditions — line-call devices used under direct sunlight by umpires tracking contested shots, telemetry dashboards opened on small phones immediately after a match. I audited all existing apps against these real environments and user types, making evidence-based changes that contributed to measurable reductions in user flow times and improved stickiness across the suite.
Designed for expansion
The suite was growing. Rather than designing each new product in isolation, I established patterns that future products could inherit — adaptable enough to accommodate a player's live scoring view, an umpire's decision interface, and a tournament manager's admin tools from the same component set. New product launches required no architectural rethink — the patterns absorbed every new user role without custom work.
Cohesive brand experience
With products for players, umpires, and academy managers, consistency across the suite was a user trust issue, not just aesthetics. One component library and one interaction language means every Zenniz product feels immediately familiar.
Active users
User stickiness
User flow times
“Jukka knows what he is doing and is able to quickly adapt to all kinds of design tasks — a great asset to development teams, fulfilling design needs, especially from a UX point of view.”
— Eero Kuusi, Co-founder & CEO at Zenniz
Shipping new features into a live marketplace
Zadaa was already the customer-favourite in Finnish peer-to-peer fashion resale — over 500,000 users and 4+ stars on both app stores before I joined. The challenge wasn't fixing something broken; it was adding new capabilities without disrupting what loyal users already loved. As Lead UI/UX Designer, I designed new features that slipped into existing flows rather than replacing them.
Research-driven
Zadaa had a history of involving power users in feature direction — the research culture was already there. My role was to make it rigorous: structuring research so insights confirmed or challenged assumptions before a pixel was pushed, not after. On a live product with 500,000 users, catching a wrong assumption in research cost hours; catching it after launch cost months.
Bidding, subscriptions & referral program
Bidding, subscriptions, and a referral program were new territory for Zadaa's users. Designing them end-to-end meant finding the right entry points in existing flows — so each new feature felt like it had always been there, not like a new section to learn.
Selling flow & search redesign
The selling flow and search UX had been built for an earlier, simpler product. With a growing catalogue and seller base, they needed work. I redesigned both to improve clarity and speed — keeping the interaction logic familiar so existing sellers didn't have to relearn.
Brand refresh
Launching Zadaa+ required a visual identity that could carry a new revenue model. I designed a refreshed Zadaa logo and a Zadaa+ sub-brand — keeping the existing brand equity intact while signalling that the product had grown beyond its original scope.
Native-feeling features
The Android app was originally a derivative of iOS. Nativizing it — aligning to Android patterns while fitting into Zadaa's existing experience — drove Google Play ratings from 4.1 to 4.6, surpassing iOS at 4.5. The principle throughout: every new feature plugged into an existing flow rather than requiring users to learn a new one.
App Store (Apple)
Google Play
“Jukka is a versatile designer with a strong orientation toward research-based development — eager to help others outside the traditional UI/UX scope.”
— Jyri Vähä-Pietilä, Co-Founder & Chief Hacking Officer at Zadaa
“Jukka has been one of the best performers — innovating and executing the needed UI/UX improvements which has led to a seamlessly flowing design.”
— Iiro Kormi, Co-Founder & CEO at Zadaa
Design leadership for a sensemaking platform
Hunome started from a proof-of-concept built by the founders and a freelancer. When I joined as Chief Design Officer, the actual product was built from scratch. The core challenge: how do you design a simple interface for something inherently complex — dozens of people each holding partial knowledge of a topic from different angles, synthesized into one navigable view?
Concept to live product
Founders' PoC to public launch and investor pitching — built end-to-end, greenfield.
Design team built from scratch
Zero to four designers: generalist CDO, graphic, UX-frontend, UI.
Analytics & feedback loops embedded
Growth-funnel dashboard embedded as the product matured, making growth patterns visible and actionable.
Design vision & strategy
Starting from scratch meant the design direction was mine to define. I set simplicity as the product's core design constraint — not aesthetic simplicity, but cognitive: the user should focus on making sense of complex topics, not on operating the tool. That principle carried through from the first wireframe to public launch — a product where usability and accessibility were built in, not bolted on.
Research & analytics
Analytics and user feedback weren't there on day one — we built the infrastructure as the product grew. I established a user-centric research process and, as the product matured, embedded an AARRR (acquisition-to-referral funnel) analytics dashboard that made growth patterns visible and actionable.
Team building
I built the design team from zero: recruiting and mentoring a graphic designer, a UX-frontend unicorn, and a UI trainee — alongside my own role as the generalist design-thinking lead. Different specializations, shared vision. Together we shipped Hunome from the ground up — concept to public launch and investor pitching.
SparkMap knowledge maps
SparkMap had no direct design precedent. A news app shows a feed; Hunome needed to show a multiplayer mind-map — dozens of people's knowledge on a topic, from different angles, synthesized and explorable at once. I designed SparkMap to make those connections visible and navigable without overwhelming the user with the complexity behind them.
Structured sensemaking
The hardest design problem in Hunome wasn't the data visualization — it was helping users do something meaningful with what they found. I designed curated content collections and guided reflection prompts to scaffold the move from information overload to informed perspective.
Unified design system
With web and mobile being built simultaneously from ground zero, I established a unified design system covering both surfaces. It gave the team a shared language, reduced design drift, and ensured every new feature had a consistent foundation to build from.
History in brief
“The clichéd work-related movie quote” — Wayne Gretzky & Michael Scott
Ye olde clients
Craft and taste that make any brand or style work.
To be continued...?
Your project here
Contact me
Send email jukka@jukkayrjonen.com Open LinkedIn linkedin.com/in/jukkayrjonenBased in Vantaa, Finland. Hybrid in the capital region, remote across Finland, Europe and Africa, async with Canada, Latin America and Oceania. Works in English and Finnish.