Senior AI Frontend Engineer

Leadtech Group builds and scales digital products used by millions of people worldwide. With over 18 years of experience, we bring together multidisciplinary teams to turn ideas into meaningful, high-impact solutions.

Within the group, MAU by Leadtech focuses on subscription-based apps and digital products. It builds on the expertise, technology and product mindset developed at Leadtech, combining proven experience with a strong focus on user value and long-term growth.

Across both brands, we share the same approach: a deep commitment to understanding people and creating experiences that make a difference — for our users and for our teams.

We work as a remote-first, international team, where flexibility and collaboration shape how we build, learn and move forward together. Our environment brings together experienced professionals across product, tech, data and design, all driven by curiosity, ownership and continuous improvement.

If you’re looking to contribute to products with real impact and grow alongside a team that values how things are built as much as what is built, we’d love to meet you.

The Role

We are a product team within Leadtech's AI-LAB. Our job is to research, prototype, develop, launch and scale challenging AI products across the Leadtech portfolio.

We're looking for a Senior Frontend Engineer who is equally strong as a product designer: someone who can take a blank canvas to a beautiful, usable, high-converting interface, then engineer it to production quality. You design the UI, you ship it, and you measure whether it works.

This is a Frontend-First role with full design ownership and full-stack reach.

What You Will Do

• Own product design end to end. You define the look, feel and flow of our products, from the first wireframe to the last pixel. There is no handoff: you design it and you build it.

• Design interfaces people love to use. You create clean, polished UI with strong visual hierarchy, typography, spacing, colour and motion. Our products should look and feel best-in-class.

• Make usability non-negotiable. You simplify complex AI capabilities into interfaces that are obvious on first use. You run quick usability tests, watch real users struggle, and fix what you find.

• Design onboarding and activation flows that convert. You own the first-run experience: sign-up, onboarding, the first "aha" moment, and the path to paid. You understand where users drop off and design to prevent it.

• Design and build high-converting revenue surfaces. Landing pages, checkout flows and paywalls are where revenue happens, and getting the best conversion from them is part of the job.

• Build and maintain the design system: tokens, components, patterns and guidelines that keep every product consistent and fast to build.
  

• Prototype fast. Turn a concept into something users can click within days, put it in front of them, and double down or discard based on what you learn.
  

• Scale what works. Once a product finds traction, you harden the codebase, keep performance and quality high as scope grows, and evolve the UX based on real user behaviour.
  

• Ship to learn. You instrument features, run A/B tests, read funnel data and iterate. Metrics are your compass.

What You Will Bring

• A strong design portfolio. You can show interfaces you designed yourself, ideally shipped products, and explain the decisions behind them. A portfolio is required to apply.

• 5+ years of frontend engineering, with deep TypeScript and React proficiency (Hooks, Context API, state management, Vite, Tailwind, Shadcn UI) and a track record of owning significant surface area.
  

• Visual design craft. You have a sharp eye for typography, layout, spacing, colour and motion. You know when something looks off and how to fix it.
  

• Usability and interaction design. You can tell good UX from bad, articulate why, and back it up with examples. You design for clarity, accessibility and low friction by default.
  

• Craft fundamentals. Design systems and component APIs built to last, responsive and mobile-first layouts, accessibility, and frontend performance.
  

• You build for the long run. You know the difference between a prototype and code that survives a growing user base, and which one a given moment calls for.
  

• AI-native in practice. You use AI throughout your design and development process by default, and you've built your own skills, agents or automations to remove repetitive work.
  

• Comfortable on the backend. Node.js, Express, REST APIs and PostgreSQL. You can build the endpoint you need rather than wait for it.
  

• Autonomous and collaborative. Given an ambiguous problem, you return with a plan, decisions made and questions surfaced early. You communicate clearly, handle feedback well, and work easily with people outside engineering.
  

• Self-driven and business-aware. You care about solving real problems and moving metrics, not just shipping features.

Bonus Points

• Previous experience launching and scaling products in a startup, venture studio or internal product team.

• Hands-on SEO experience: technical audits, SSR/SSG rendering strategy (Next.js), structured data, international and multi-market pages.

• Familiarity with experimentation and analytics tooling (Amplitude, GA4).

• Experience with LLM engineering: prompt tuning, RAG pipelines, vector databases, or agentic frameworks.

• A genuine passion for AI and a habit of staying on the frontier: new models, protocols, and developer tooling.

How to Apply

A portfolio is required. Please share a link (Figma, personal site, or live products) showing interfaces you designed and built yourself. Include a short case study of one of them: what problem it solved, what you tried, and what the results were. Where possible, also link a repository or live product that shows the engineering side.

Benefits

WHY LEADTECH

• Diversified app portfolio with millions of active users in a high-growth non-gaming vertical.

• Mature data infrastructure: BigQuery, Looker, AppsFlyer, and a proprietary analytics stack for fast decision-making.

• Experimentation culture: real autonomy to propose and ship changes in production.

• International team, dynamic environment, and the opportunity for direct P&L impact.

• Competitive compensation package + benefits (flexible hours, health insurance, training).

Growth and career development

• At Leadtech, we prioritize your growth. Enjoy a flexible career path with personalized internal training and an annual budget for external learning opportunities.

Work-Life balance

• Benefit from a flexible schedule with flextime and the option of working full remote or from our Barcelona office. Enjoy free Friday afternoons with a 7-hour workday, plus a 35-hour workweek in July and August so you can savor summer!

Comprehensive benefits

• Competitive salary, full-time permanent contract, and top-tier private health insurance (including dental and psychological services).

• 25 days of vacation plus your birthday off, with flexible vacation options—no blackout days!

Unique Perks

• If you wish to come, in our office in Barcelona you’ll find it complete with free coffee, fresh fruit, snacks, a game room, and a rooftop terrace with stunning Mediterranean views.

• Additional benefits include ticket restaurant and nursery vouchers, paid directly from your gross salary.

• Join us in an environment where you’re free to innovate, learn, and grow alongside passionate professionals. At Leadtech, you’ll tackle exciting challenges and be part of a vibrant team dedicated to delivering exceptional user experiences

Sounds good? Apply now! We’re looking forward to getting to know you.

Equal Employment Opportunity Employer:

Leadtech is an Equal Employment Opportunity (EEO) Employer, which means we encourage applications from people with different backgrounds, interests, and personal circumstances. Our team welcomes applicants regardless of their race, gender, age, religion, nationality, sexual orientation, gender identity, gender expressión and/or disabilities. All we need is your high energy, skills, and willingness to be a part of a great project!

Location

You'll have the flexibility to choose whether you'd like to come to the office every day, from time to time, or work fully remote. We want you to find the best combination for you.

If you prefer to be surrounded with amazing people, our exceptional office is in Barcelona’s Blue Building, located right on the city's seafront. Besides our stunning views, you’ll enjoy our office perks such as free fruit, snacks, and coffee and you’ll also be able to take part in our Mario Kart and table tennis competitions.

The personal data you provide will be processed in order to manage your candidacy for the corporate selection processes that fit your profile. If you wish, you can exercise your rights of access, rectification or cancellation by writing to our address (Avenida Litoral, 12-14, 5ta planta. Barcelona. 08005) or to the email address privacy@leadtech.com.