Local time in London: —:—

I make complicated products feel simple.

Nine years designing the systems behind how people buy — luxury retail, marketplaces, and the enterprise tools that keep them running. Currently at Phillips, leading design across Business Tooling and Client-Facing products. Previously Harvey Nichols, THE OUTNET and RealifeTech.

Available for new work

Brands worked with

01 — Selected work

Six projects where the domain was genuinely hard and someone still had to use it.

  1. 01 Fenty Beauty A Shade Finder for 40 foundation shades, built to survive a launch aimed at 100 million fans. £1M+ in week one and zero minutes of downtime while competitors went dark. eCommerce Launch Research Harvey Nichols 2017
  2. 02 iOS Refresh Rebuilt navigation, discovery and shopping flows around two customer segments. 89 usability issues triaged; filter use up 67% and sort use up 104% in Firebase testing. A/B testing Native app Product growth THE OUTNET — YOOX Net-A-Porter 2019—2021
  3. 03 Campaign Automation Powerful segmentation nobody could use. Progressive disclosure turned a technical tool into a self-serve one — and turned a data platform into a revenue engine that won the Phoenix Suns. B2B SaaS Enterprise design Product-market fit RealifeTech 2021—2022
  4. 04 Bridging the eCommerce World Unified Dropshop, PhillipsX and Perpetual from three fragmented legacy systems onto one Shopify architecture — and removed the developer dependency from every content update. Digital transformation Go-to-market Shopify Phillips 2022—Present

    Under NDA. Unlock it here, or ask me for a passphrase.

  5. 05 Saleroom Ecosystem Replaced a legacy third-party auction platform with four tools designed as one ecosystem — the client saleroom, Clerk Console, Auctioneer TV and Auctioneer Tablet, built so both sides of a live sale stay in step. Business tools Digital transformation Phillips 2023—Present

    Under NDA. Unlock it here, or ask me for a passphrase.

  6. 06 Knowing Your Client Turned KYC and AML from a manual burden spread across four systems into one platform, organised around a single idea: Client Operational Readiness. Business tools Compliance Enterprise design Phillips 2023—Present

    Under NDA. Unlock it here, or ask me for a passphrase.

02 — How I work

Four things I hold to, whatever the brief turns out to be.

  • 01

    Product Growth & Product-Led Growth

    Strategy + Execution

    I design for the metric, not just the screen — audience strategy, payment types, campaign mechanics. When growth stalls it is usually the infrastructure rather than the talent, and that is a design problem too.

  • 02

    Workshop Facilitation

    Discovery + Alignment

    I run structured workshops that turn ambiguous briefs into clear, shared problem statements. From stakeholder alignment sessions to design sprints, I create the conditions for better decisions — earlier in the process, when they’re cheapest to make.

  • 03

    Building Products

    End-to-end delivery

    I work across the full product design lifecycle — from research and ideation through to detailed specs and engineering handoff. AI tooling has made a working prototype nearly free, so I would rather build the thing while everyone is still in the meeting than describe it and book another one.

  • 04

    Scaling Design Systems

    Systems thinking

    I build and scale design systems that give teams the freedom to move fast without losing consistency. From component libraries to documentation frameworks, I create the shared language that lets design and engineering work as one — not in parallel silos.

03 — Experience

Nine years, one throughline: commerce that has to work at scale.

  1. 2022 — Present

    Phillips

    Senior Product Designer

    Leading product design across three eCommerce platforms (Dropshop, PhillipsX, Perpetual), the Saleroom ecosystem and a KYC compliance platform. Driving a three-year digital transformation on Shopify.

  2. 2021 — 2022

    RealifeTech

    Mid/Senior Product Designer

    Designed Campaign Automation for enterprise venues in sport and entertainment, including the Phoenix Suns. B2B SaaS from research through to shipped product.

  3. 2019 — 2021

    THE OUTNET — YOOX Net-A-Porter

    Mid Product Designer

    Led the iOS Refresh from a UX audit of 89 issues to a shipped redesign, delivering +67% filter usage and +104% sort usage through Firebase A/B testing.

  4. 2017 — 2019

    Harvey Nichols

    Junior UX Designer

    Fenty Beauty launch (£1M+ week one, zero downtime), PDP redesign (+34% add-to-bag, +27% mobile conversion), PWA and checkout redesign, plus the in-house user testing programme.

  5. Before 2017

    Fandango Digital · Website Success · KAM Insights · Kantar Retail

    Web Designer · UX Consultant · Multimedia Designer

    Infographics, web design and UX consultancy across agency and research settings.

04 — References

What it is like on the other side of the work.

  • Jason is a breath of fresh air that brings great ideas, pragmatism and fun to the table.
    Jack Horton Delivery Manager, Virgin Media O2
  • Jason was extremely easy to work with — he transformed the look and feel of our Product Details Pages.
    Conor McGann CSS Shopping Ads Consultant, PerfX at Google
  • Jason is a very hard working UX Designer who puts customers at the heart of his work.
    Chris Bayley Head of Digital Solutions, Lewisham Council

05 — Contact

Jason Castañeda, Senior Product Designer

Let’s build something worth using.

Looking for a Senior Product Designer, or want to talk through a problem that will not sit still? Either is a good reason to write.

Based
London, United Kingdom
Availability
London-based · Remote-friendly · Contract & permanent
Local time
—:—

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