Services

Senior UX expertise, at every stage.

From the first research question to a production-ready design system, UXellence comes in where your product needs the most experienced hands. Matthaios Mantzios leads every engagement himself, and we take on a limited number at a time.

Six services and a retainer

UX practice

UX strategy & design leadership

We work with product teams and stakeholders to define a UX vision that ties user needs to business objectives, then help your team put it into practice. Ideal when you need senior direction, a design operating model, or a partner to help an in-house team raise the quality of its work.

  • Defining the experience vision
  • Design operations & in-house team support
  • Roadmap alignment with stakeholders

Format: a fixed 4–6-week engagement, or a monthly retainer. Price: quoted after the discovery call.

UX strategy and leadership in detail

Research & usability testing

We uncover what your users actually need through interviews, surveys, usability testing and behavioral analysis, and turn what we learn into design decisions you can defend. Test an idea before you build it, and check that what you've shipped works.

  • Generative & evaluative research
  • Moderated & unmoderated usability testing
  • Insight synthesis & prioritized findings

Format: one study, 2–4 weeks, fixed scope. Price: quoted after the discovery call.

Research and testing in detail

Product & interface design

We design interfaces grounded in research, and structure content and navigation so that complex products feel simple, from information architecture and wireframes to production-ready designs your engineers can build without guessing.

  • Information architecture, navigation & findability
  • Wireframes, prototypes & high-fidelity interfaces
  • Interaction design and design-to-development handover

Format: a fixed-scope project, typically 4–12 weeks. Price: quoted after the discovery call.

Product and interface design in detail

Design systems

We build and maintain scalable design systems that ensure visual and interaction consistency across products and teams — while accelerating delivery and reducing design debt.

  • Component libraries & design tokens
  • Governance & contribution models
  • Accessibility built into every component

Format: a fixed-scope build, 6–12 weeks, then optional monthly support. Price: quoted after the discovery call.

Design systems in detail

UX audits

We evaluate your existing digital product and deliver prioritized, actionable recommendations that improve usability, engagement and conversion — a fast way to find high-impact wins.

  • Heuristic & expert evaluation
  • Conversion & funnel review
  • Prioritized, effort-ranked recommendations

Format: a one-journey audit in five working days, credited against the full audit; or the full audit, fixed scope, 2–3 weeks. Price: €1,200 + value added tax (VAT) for the one-journey audit; the full audit quoted after the discovery call.

UX audits in detail

Team training

Practical workshops for your designers, developers and content authors, on UX methods and on building to the Web Content Accessibility Guidelines (WCAG) 2.2 and the European Accessibility Act (EAA).

  • UX methods: research, design reviews and handover
  • Accessibility: WCAG 2.2 and the EAA, by role
  • Workshops matched to your team and product

Format: half-day or full-day workshops, on site in Athens or remote. Price: quoted after the discovery call.

Ask about team training

Senior UX on call

Up to three tasks a month from a senior UX consultant, for the decisions your team is stuck on. See a sample month (PDF).

  • Consulting: a recommendation on one specific task, with the reasoning in writing
  • Flow audit: one flow or up to 10 screens, with written findings in order of priority
  • Pre-release review: one page or one flow, with its emails or messages
  • Each task delivered within five working days, and one 60-minute call a month with the people who have to act

Format: monthly, invoiced. Tasks go on a shared board; anything bigger we discuss and price before it starts. Unused tasks carry over for up to three months; pause or cancel any month. Price: €1,650 + VAT a month. Year-end pack: 9 tasks €4,500 + VAT or 15 tasks €7,000 + VAT, bought by 31 December 2026 and used by 31 March 2027, when unused pack tasks expire; paid up front.

Senior UX on call in detail

Not sure where to start?

Most engagements begin with a short discovery call. We'll help you scope the right first step — often a UX audit or a focused research sprint.

Pick a free 30-minute slot.

Or send a message

For specific obligations

Specialist services

AI oversight testing

Where people check an AI system’s outputs before they take effect, we test whether that check works. Known-wrong outputs go into the live queue, unannounced, and we measure how many your reviewers catch against a threshold you commit to in advance. Fixed scope, fixed price.

  1. Oversight readiness review €1,650 + VAT · 5 working days
  2. Seeded-error audit €8,250 + VAT · about 4 weeks
  3. Audit and retest €12,100 + VAT

The Greek public-sector Registry declaration with a tested oversight check includes a shorter, one-week test with your own staff, as evidence for the declaration's item on measures for safe operation (item θ). The seeded-error audit is the deeper test and runs for two weeks.

AI oversight testing in detail

AI Registry declaration: Greek public sector

Under Greek law (Law 5321/2026, Article 21), public-sector bodies must declare the AI systems they use, or plan to use, in the national AI Registry; systems in use before July 20, 2026 must be declared by December 31, 2026. We prepare the declaration and test whether human oversight of the system actually works. Fixed scope, fixed price, delivered in Greek.

  • The eleven required items, ready to submit
  • A documented classification under the EU AI Act
  • A one-week oversight test with your own staff

Format: three fixed packages, from €1,500 + VAT per system. The free guide is in Greek.

See the three packages (in Greek)

The same discipline, three fields

What a review usually misses

A review tends to cover the top layer. These three diagrams show what sits beneath it — the part that decides whether the work holds up in use.

The UX iceberg

6 visible · 15 underneath

The screens are the part of the work that is easiest to review, and the smallest part of what determines the outcome.

See the full iceberg

The Design systems iceberg

6 visible · 16 underneath

A component library is an artifact. A design system is an agreement about how work gets made.

See the full iceberg

The Accessibility iceberg

6 visible · 18 underneath

A page can pass every automated check and still be unusable with a screen reader.

See the full iceberg
How we work

A clear, collaborative process

Every engagement is tailored, but the backbone stays the same — so you always know what's happening and why.

Understand

We start with your business goals, constraints and users, reviewing what exists and what's missing.

Define

We frame the real problem, shape the information architecture and agree on how we'll measure success.

Design

We wireframe, prototype and test with real users, and iterate until the experience works for them.

Deliver

We hand over production-ready design and documentation, and a system your team can extend on its own.

Where does your product need senior UX?

Tell us what you're working on. We'll recommend the right first step.

Start a project