Sign up to access all features of our service.
  • Job search
  • Favorites
  • Create a CV
    New
  • Salaries
  • Subscriptions

Senior Frontend Engineer

Full-time

Treatwell

We build and operate Connect, a SaaS platform for the beauty & wellness industry that helps entrepreneurs run their businesses more effectively.

Our web products are used daily by tens of thousands of people across 13 European countries.

Our teams own their areas from initial idea and design through deployment and operations. We focus on writing maintainable, scalable code while balancing legacy and modern technologies. We encourage engineers to experiment with new ideas, learn from mistakes, and improve our systems continuously.

You will be responsible for:

  • Take ownership of the frontend experience from design to deployment to operations.
  • Pair with engineers, designers, and PMs to ship features every cycle, iterating based on real usage and feedback.
  • Participate in design and code discussions, making trade-offs and decisions that affect the product and the team.
  • Maintain a strong focus on automated testing, applying the testing pyramid to ensure unit, integration, and end-to-end coverage.
  • Improve our frontend observability by adding metrics, dashboards, and alerts with tools like Datadog, Sentry, and web vitals to catch issues before they impact users.
  • Be an active part of the Frontend Guild, collaborating with other engineers to share ideas, improve standards, and tackle cross-team frontend challenges.
  • Lead technical discussions about trade-offs in features, architecture, and UX, helping the team make informed decisions that balance product goals and engineering constraints.
  • Navigate a hybrid codebase, balancing work between legacy systems and modern React/TypeScript.

Our frontend stack:

The frontend stack is a mix of legacy and modern technologies. The application originally grew as a Backbone-based product, served through Node/Express with EJS templates, and there are still important areas of the product that work this way today. At the same time, the team is actively migrating the frontend toward a more modern React and TypeScript architecture, delivered into the existing application through a gradual, page-by-page and feature-by-feature transition.

In practice, that means most new development now happens in the modern React/TypeScript stack, using tools and patterns such as React Query, Storybook, Jest, and Cypress, while some work still involves the legacy Backbone codebase and the integration layer between old and new parts of the app.

Vacancy posted a month ago
Similar jobs that could be interesting for youBased on the Senior Frontend Engineer in Kingdom of Spain vacancy
  •  ...About the role Senior Frontend Engineers work across our product domains. Your team match will reflect your strengths, interests and where you can contribute most. Across every team, the model is the same: small, autonomous groups, a weekly release cycle and ownership... 
    Senior
    Full time

    Trading 212

    Kingdom of Spain
    10 days ago
  •  ...About the role Senior Backend Engineers work across our backend organisation. Your team match will reflect your strengths, interests and where you can contribute most. Across every team, the model is the same: small, autonomous groups, short release cycles and ownership... 
    Senior
    Full time

    Trading 212

    Kingdom of Spain
    10 days ago
  •  ...We are looking for a Senior Developer Advocate (Education focus) to: Teach a community of automation, no-code and open source builders, meeting them where they already are with practical how-tos, helping them get unstuck, and building relationships with our most active... 
    Senior
    Full time

    N8n

    Kingdom of Spain
    a month ago
  •  ...As a Senior Data Scientist at Docplanner, you will help transform complex data into actionable insights and scalable machine learning...  ...Product areas, partnering closely with business stakeholders, engineers, and analytics teams. You will own data science and BI... 
    Senior

    Docplanner

    Kingdom of Spain
    a month ago
  •  ...This is a remote role . The role of Senior Global Service Associate (‘GSA’) forms the backbone of the HSP Group Customer service delivery experience. Acting as the primary contact point for our customers, the Senior Global Service Associate will perform and coordinate... 
    Senior
    Full time
    Local area
    Remote work

    HSP Group

    Kingdom of Spain
    21 days ago
  •  ...About the role Staff Frontend Engineers shape architecture and engineering direction across product teams while remaining close to the code...  ...on risks and decisions that cross team boundaries. Mentor senior engineers, raise review quality and make sound frontend judgement... 
    Full time

    Trading 212

    Kingdom of Spain
    10 days ago
  •  ...cancellations, refunds, and bookings over chat and voice for some of the world's largest travel brands. We're looking for a senior full stack engineer to anchor this product, owning the realtime and voice layer end to end while building across React/TypeScript front... 
    Senior
    Full time
    Work experience placement
    Remote work
    Work from home
    Home office

    Hopper

    Kingdom of Spain
    9 days ago
  •  ...At Workana, we are looking for a Senior Backend Developer (Golang/Python) to support our client in the creation and maintenance of...  ...(mandatory) and Python . Strong foundation in software engineering principles, clean architecture, and design patterns. Proven... 
    Senior
    Temporary work

    Workana

    Kingdom of Spain
    a month ago
  •  ...quality and care for patients worldwide. Since 2019, our team has engineered FDA-cleared computer vision capabilities for the interpretation...  ...dental care around the world. Key Responsibilities ~ The Senior Product Designer will play a critical role in shaping the... 
    Senior
    Full time
    Worldwide

    Pearl

    Kingdom of Spain
    a month ago
  •  ...Reliability, work as an important member of the technical support team providing senior level technical knowledge on our customer issues. Work with and foster relationships with the development engineering team to ensure tracking on engineering escalations, bugs and feature... 
    Senior
    Full time

    Sysdig

    Kingdom of Spain
    a month ago
  •  ...As Senior Sales Director, EMEA South , you will lead our high-growth sales engine across France, Spain and Italy . You will inspire, coach, and scale a talented team of Enterprise Territory Managers, Commercial Territory Managers to exceed ambitious revenue targets... 
    Senior
    Full time
    Shift work

    Tenable

    Kingdom of Spain
    a month ago
  •  ...We’re looking for a Full Stack Developer who has experience with frontend conversion, backend automation, and data-driven optimization. You’ll build high-performing landing pages and checkout experiences, set up accurate tracking and analytics across our eCommerce stack... 
    Full time
    Remote work

    Plateful

    Kingdom of Spain
    a month ago
  •  ...implemented in Go and running on Kubernetes across all major Cloud service providers ( GCP , Azure , AWS ). We also have engineers working on Prometheus , Grafana Agent , Mimir proxies , and OpenTelemetry . As a company we are remote-first and global... 
    Senior
    Full time
    Local area
    Remote work

    Grafanalabs

    Kingdom of Spain
    a month ago
  •  ...Senior Product Manager - Openbank App (Digital Channels) Country: Spain IT STARTS HERE Santander ([ is evolving from a global...  ...mobile app for Individuals. You will partner closely with Engineering, Design/UX, Data, Operations, Customer Growth, Customer Needs,... 
    Senior
    Full time
    Work at office
    Shift work

    Banco Santander S.A.

    Kingdom of Spain
    2 days ago
  • We are hiring a Talent Acquisition Senior Specialist (Technology & Product) in our People area in Spain ! This is a Remote - Spain position, meaning you can work from anywhere within the country. Please note that this role is only open to candidates in Spain. As a Talent... 
    Senior
    Full time
    Remote work

    Gympass

    Kingdom of Spain
    a month ago
  • As Senior Sales Director, EMEA South , you will lead our high-growth sales engine across France, Spain and Italy . You will inspire, coach, and scale a talented team of Enterprise Territory Managers, Commercial Territory Managers to exceed ambitious revenue targets. You... 
    Senior
    Full time

    Tenable

    Kingdom of Spain
    a month ago
  • About the role We are looking for a Senior Product Manager to own and evolve Create & Design, the product where every Typeform begins. Every customer starts here. The builder is where ideas become forms, where brands come to life, and where our promise of beautifully designed... 
    Senior
    Full time

    Typeform

    Kingdom of Spain
    a month ago
  •  ...features most agencies never touch. Their strategies are not public, their standards are high, and their results do the talking. They grow fast because the work is that good, and they keep the team senior and selective on purpose. Their average client stays with them well...
    Senior
    Full time

    Paired

    Kingdom of Spain
    a month ago
  •  ...contribution is welcomed. And now we are looking for a Staff Architect (Senior Solution Architect) to join us as part of our team. About...  ...technical standards, collaborating closely with Product and Engineering to design cost-efficient, scalable solutions that maximize... 
    Senior
    Interim role
    Remote work
    Flexible hours

    SPD Technology

    Kingdom of Spain
    a month ago
  •  ...collaboration, encourage professional and personal growth, and foster a supportive and flexible work environment where everyone’s contribution is welcomed. And now we are looking for a Staff Architect (Senior Solution Architect) to join us as part of our team. About the pro...
    Senior
    Full time
    Flexible hours

    SPD Technology

    Kingdom of Spain
    a month ago
  • What you will own Design and evolve core platform services and internal APIs consumed by multiple teams. Drive architectural initiatives such as gRPC migration, eventing/pub-sub foundations, and platform refactors. Own and improve control-plane and cluster-api components...
    Senior
    Full time

    Qdrant

    Kingdom of Spain
    a month ago
  •  ...and internal teams, shaping and optimizing our global benefits provisions across a diverse portfolio of international markets. As a Senior Specialist , you operate with a high degree of autonomy and commercial acumen. You are the vital connector between our global... 
    Senior
    Contract work

    Oyster

    Kingdom of Spain
    a month ago
  • Your Responsibilities: Own production PostgreSQL reliability: HA design, Patroni, PgBouncer, replication, failover, upgrades, vacuum/bloat control, query tuning, locks, indexes, capacity, backups, PITR, and restore validation. Improve disaster recovery and operational evidence...
    Senior
    Full time

    Alex Staff Agency

    Kingdom of Spain
    a month ago
  • Role Overview We are looking for a Senior QA Engineer to ensure the quality, reliability, and accuracy of trading and related products for a centralized crypto exchange. This role requires strong technical knowledge and an understanding of complex financial systems. You... 
    Senior
    Full time

    Freedx

    Kingdom of Spain
    a month ago
  • Key Responsibilities Complex employee relations (ER) matters Act as a senior HR expert for complex employee relations (ER) matters across your allocated countries, with particular in-depth knowledge across multiple European countries. Provide pragmatic, solutions-focused... 
    Senior
    Full time
    Local area

    Oyster

    Kingdom of Spain
    a month ago
  •  ...Reliability, work as an important member of the technical support team providing senior level technical knowledge on our customer issues. Work with and foster relationships with the development engineering team to ensure tracking on engineering escalations, bugs and feature... 
    Senior
    Full time

    Sysdig

    Kingdom of Spain
    a month ago
  • $80k

    About Darkroom Darkroom is the leading next-generation growth marketing firm engineering the brands of tomorrow. Founded in 2017, we set out to redefine what a modern agency could be, by replacing the inertia of legacy advertising behemoths with a model built for speed,... 
    Senior
    Full time

    Darkroom

    Kingdom of Spain
    a month ago
  •  ...digital experiences that empower millions of entrepreneurs? As a Senior Product Designer , you'll play a pivotal role in shaping the...  ...research through delivery—working closely with Product Managers, Engineers, Researchers, Data teams, and AI specialists. You'll combine... 
    Senior
    Full time

    Jimdo

    Kingdom of Spain
    a month ago
  • €86k - €122k per year

    Affirm is reinventing credit to make it more honest and friendly, giving consumers the flexibility to buy now and pay later without any hidden fees or compounding interest. Affirm’s Identity team is mission-critical to the customer checkout experience. When a customer chooses...
    Senior
    Full time

    Affirm

    Kingdom of Spain
    a month ago
  • Role Summary Are you a governance-minded lawyer who thrives on ambiguity, ownership, and building something from scratch? As our Senior Counsel, Governance , you'll join Oyster's Legal team as the dedicated governance and entity-formation counsel supporting Global Expansions... 
    Senior
    Contract work

    Oyster

    Kingdom of Spain
    a month ago

Do you want to receive more vacancies?

Subscribe and receive similar vacancies to Senior Frontend Engineer. Be the first to apply!