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Case Study 01

Rethinking the Home & Garden App

Transforming product, team architecture & AI prototyping across a 3-year ecosystem journey.

Not only was the legacy app failing — so was the way it was built. This is how a new team architecture, a design-system foundation, and an AI-powered prototyping pipeline rebuilt both the product and the process behind it.

Role
Lead UX Consultant & Prototyping Architect
Timeline
3+ years — ongoing initiative
Team & Governance
1× UX Lead, 1× Guidelines / Design System Architect, N Application Designers (robotics, irrigation, e-commerce…)
Tools & Tech
Figma, v0 (Vercel), Zeroheight, Jira
A user holding a smartphone showing the redesigned Kärcher Home & Garden app onboarding screen, with a yellow Kärcher pressure washer in the garden behind.
A user holding a smartphone showing the redesigned Kärcher Home & Garden app onboarding screen, with a yellow Kärcher pressure washer in the garden behind.

Impact at a glance

2.8 → 4.6App Store rating
70%Faster feedback via v0 code prototypes
100sDevelopment hours saved
3+ yrsOngoing ecosystem initiative
On this page

01 · The status quo — the legacy era

At the start of the initiative the Home & Garden app was in serious trouble. The problems ran deeper than the interface: both the product and the way the design team worked behind the scenes lacked any durable structure.

The symptoms in the product

  • App Store rating 2.8 ★: Frustrated users, drop-offs while pairing IoT devices, and confusing menus.
  • Feature sprawl: The product had grown as a collection of isolated functions — with no unified navigation or interaction concept.
  • UI & tech debt: Dated interfaces, inconsistent spacing, and a weak visual hierarchy.

The causes in the organization & process

  • No guidelines, no design system: Every new function was drawn from scratch — producing dozens of variants of the same buttons, inputs, and modals.
  • Figma & permission chaos: No project structure, component drafts stored locally, no versioning standard, and unclear edit/view rights for stakeholders.
  • Silo work: Product owners from the hardware divisions (e.g. mowers vs. irrigation) worked in isolation from the e-commerce and app teams.

02 · The transformation architecture

To make the app scalable for the long term we didn’t just rework the interface — we restructured the entire UX organization around a clear governance model that stays consistent while responding fast to product demands.

1× UX Lead — governance & alignment

Strategic direction, stakeholder alignment, process governance, and orchestration across the whole initiative — the role I owned as the single point of accountability for UX quality.

The team beneath the lead

1× Guidelines & System Architect

Owns maintainability, token architecture, pattern libraries, and the Zeroheight documentation — the guardian of the system.

N × Application Designers

One dedicated designer per domain — e.g. robotics, smart irrigation, high-pressure washers, and e-commerce — designing deep within their field.

Stakeholder alignment & meeting culture

Weekly UX / PO alignment

A regular sync with the hardware product owners to surface roadmap dependencies early.

Cross-functional design reviews

Shared feedback loops with developers, product owners, and e-commerce teams before every sprint sign-off.

Workshop board mapping the UX design and meeting workflow — roles, meeting cadences, quality gates, and the end-to-end feature flow on sticky notes.
Workshop outcome with product owners & designers ++ stakeholders from marketing, development, etc. to map out the best-case workflow and blind spots.

03 · Feature creation & dual-track agile

A key element of the transformation was introducing two distinct paths to feature development — so routine iteration and brand-new product categories each get the right level of rigor.

Path 01

Standard feature flow — agile sprints

For established modifications and iterative UI components, the UX process runs in sync with the two-week development sprints. Dual-track agile keeps the discovery sprint one step ahead of the delivery sprint.

  1. Discovery
  2. Design
  3. Delivery sprint
  4. Ship

Path 02

New product integrations — Google Design Sprint

When an entirely new product category (e.g. a new autonomous robot) enters the ecosystem, the five-day Google Design Sprint is used to de-risk it before any estimate is made.

  1. Map & target
  2. Sketch
  3. Decide
  4. Prototype
  5. User test

The advantage: before any effort estimate lands in the dev sprints, a valid concept — already tested with real users — is on the table.

04 · Continuous research & multi-level testing

Quality assurance was anchored as a fixed part of the design lifecycle, split across two testing levels — one before development, one live in production.

01

Concept & UX testing

Method & scope

Figma prototypes and usability labs with target-group readings.

Goal

Identify navigation hurdles and wording misunderstandings before development starts.

02

Live product testing

Method & scope

A/B testing, telemetry analysis, in-app NPS, and micro-surveys.

Goal

Verify conversion (shop), drop-off (IoT pairing), and long-term usage in live operation.

Decision-tree guideline that classifies each usability finding as low, medium, high, or critical based on task impairment, difficulty to work around, and frequency.
A shared severity guideline turns every usability finding into a repeatable decision — three questions route it to low, medium, high, or critical, so prioritization stays objective instead of opinion-driven.

05 · System architecture, guidelines & Figma governance

  • Design tokens & atoms

    Colors, typography, spacing, radii, elevation, and a bespoke icon set — the CI-compliant base every other layer inherits from.

  • Patterns & base components (web & app)

    Universal UI building blocks — buttons, text fields, modals, card containers, and navigation elements — shared across every screen.

  • Domain-specific components

    Highly specialized modules for individual domains — e.g. interactive zone-cleaning maps for robots or irrigation timer dials.

UX Guidelines overview — inventory to semantic system

Inventory & foundation: color system, from inventory to semantic applications

1 / 6Inventory & foundation: color system, from inventory to semantic applications

06 · Documentation

Every component, token, and guideline is documented centrally in Zeroheight — a living reference that pairs the Figma component library with usage rules, do/don’t guidance, interaction specs, and token nomenclature. Developers and designers read from the exact same source, so the system stays consistent as it scales and onboarding no longer depends on tribal knowledge.

Living documentationGuidelines 3.0 on Zeroheight
Open documentation

07 · Deep dive — next-gen AI prototyping (Figma to v0)

Classic Figma prototypes hit their limits with dynamic IoT data streams, live robot maps, and synchronous device-status messages. Static click-paths couldn’t reflect the complexity of operating real live devices.

The bottleneck

Development cycles for test builds were expensive and time-intensive, and static prototypes under-represented real device behavior — so concepts stayed unvalidated until costly code already existed.

The vibe-coding workflow

The existing Figma component library was connected to AI code generators (v0 by Vercel & Claude): extract the design tokens, hand them to v0’s prompt system, generate interactive React/Tailwind prototypes, feed in real JSON data streams, and validate the running web app on real smartphones — all before the first development sprint.

Step 01

Token & pattern mapping

Extract Figma design tokens (colors, spacings, Tailwind config) and hand them to v0’s prompt system to configure the prompts.

Step 02

Vibe coding & iteration

Generate fully interactive React/Tailwind code prototypes through natural language and component references.

Step 03

IoT data simulation

Wire real JSON data streams (e.g. battery level, live robot position) into the UI components to test genuine data flows.

Step 04

Stakeholder & user validation

Test the runnable code prototype on real smartphones before the first development sprint begins.

Live prototype

The Kärcher Pilot — the main outcome of this pipeline — built in just a few hours with v0 on top of our existing design system. Explore it live below.

kaercher-pilot.vercel.appOpen in new tab ↗
“Fail ultra fast, succeed even faster.”
AI prototyping principle

08 · Impact & retrospective

  1. Year 1

    Foundation & restructuring

    Consolidated the Figma account, built the core team, released the first modular design system, and fixed the acute pairing hurdles in the app.

  2. Year 2

    Scalability & integration

    Embedded the Google Design Sprints, introduced the Zeroheight documentation, and reached the 4.0-star mark in the App Store.

  3. Year 3

    AI prototyping & ecosystem maturity

    Connected the Figma component library to v0 / Vercel (the vibe-coding pipeline), integrated the AI chatbot, and stabilized the rating at 4.6 ★.

09 · Outcome

What began as a failing legacy app is now the reliable control center for Kärcher’s connected Home & Garden devices. Rebuilding both the product and the way it is built lifted the App Store rating from 2.8 to 4.6, cut feedback loops by roughly 70% through v0 code prototypes, and saved hundreds of engineering hours — while the shared design system and Zeroheight documentation keep every new device team shipping consistently. The result is a living ecosystem instead of a one-off release: download it on both major stores.

Download the app