Research, strategy, design and design systems, from the first question to the shipped product.
Prefer to talk first? Book a free 30-minute call. Want a smaller first step? A one-journey audit, €1,200 + VAT, in five working days.
All-time-high satisfaction across a telecom's web touchpoints
Fewer overdue payments after a billing & self-service redesign
Accounts on a national digital-identity platform
Most client names are covered by non-disclosure agreements. Full context on the Work page.
Matthaios has led UX work across seven sectors.
Both have a fixed price and a clear deliverable, and both are open to teams that haven't worked with us before.
Fixed price · 5 working days
Find what stops people on one journey, and what to fix first.
€1,200 + VAT · by card or invoice
The full fee is credited against a full UX audit.
Monthly · cancel any month
Up to three senior UX tasks a month, for the decisions your team is stuck on.
€1,650 a month + VAT · up to 3 tasks
Year-end pack: 9 or 15 prepaid tasks, bought by 31 December. See the terms
Prices exclude value added tax (VAT). Businesses in other European Union (EU) countries with a valid VAT number are invoiced under reverse charge; Greek businesses are charged Greek VAT.
Something else? Improve a product · Prove a human check on AI works · Δημόσιος τομέας
Matthaios Mantzios leads every engagement himself, and we take on a limited number at a time.
Senior direction, a design operating model, or a partner to help an in-house team raise the quality of its work.
Interviews, usability testing and behavioral analysis, turned into design decisions you can defend.
Information architecture, wireframes and production-ready interfaces your engineers can build without guessing.
Component libraries, design tokens and the governance that keeps a system in use.
All six UX services, team training and the specialist services
Telecom · Digital identity
Product vision for an identity platform that grew past 5 million user accounts.
Telecom · Brand merge
A research-led merge across every digital interface: web-touchpoint satisfaction at an all-time high of 94%.
Self-service · Billing
Call-center data set what to fix: 90% satisfaction with online payment, overdue payments down 40%.
Writing on UX Planet, Fast Company and The Decision Lab, mentoring on ADPList, and the frameworks and tools below.
An open framework for designing and testing the interfaces through which people oversee AI systems.
What a review usually misses in UX, design systems and accessibility.
Twenty yes/no checks for any screen where a person reviews AI output.
The second edition of the guide to WCAG 2.2, the Americans with Disabilities Act and the European Accessibility Act.
UXellence is the UX consultancy of Matthaios Mantzios, a UX design leader with 18+ years of experience. It provides full-lifecycle UX services — strategy, research, product and interface design, design systems and accessibility — for organizations that need senior expertise across the entire product lifecycle.
UXellence is based in Athens, Greece, and works with clients internationally on a remote-first basis.
Contact UXellence at matthaios@uxellence.gr or through the contact form. Most engagements begin with a short discovery call to scope the right first step. A priced offer, such as the one-journey audit, starts the same day you ask for it, and Senior UX on call starts with a free 30-minute call.
Up to three tasks a month for €1,650 + VAT: consulting (a recommendation on one specific task, with the reasoning in writing), a flow audit (one flow or up to 10 screens) or a pre-release review (one page or one flow). Each task is delivered within five working days, with one 60-minute call a month. Anything bigger we discuss and price before it starts, and unused tasks carry over for up to three months. See the terms.
Matthaios Mantzios leads every engagement himself, and we take on a limited number at a time.
Most client names and project details are covered by non-disclosure agreements, so our case studies describe the industry, the problem and the result instead.
Tell us about your product and the problem you're solving. You'll get a candid view of where senior UX will make a measurable difference, and where it won't.
Start a projectPrefer to talk first? Book a free 30-minute call.