CRO Junior Developer

Description

Job Summary: Flat 101 is seeking a CRO Junior Developer with curiosity about web optimization and proficiency in HTML, CSS, and JavaScript to bring digital experiments to life and improve customer conversion. Key Highlights: 1. Development of A/B tests and customizations in HTML, CSS, and JavaScript. 2. Learning testing tools such as VWO, Adobe Target, and Optimizely. 3. Ongoing training and mentoring to strengthen your skills. DESCRIPTION At Flat 101, we have spent years helping our clients improve their digital performance. We run **tests, experiments, and personalizations**… essentially, we break things in a controlled way so they later work better. And now, we want to bring on board someone eager to learn, ready to get hands-on, and with a healthy dose of "What if we try this?" in their DNA. Do you know HTML, CSS, and JavaScript, and are you curious about why some websites convert while others don’t? Then keep reading — because **we’re hiring a CRO Junior Developer.** You don’t need prior experience with testing tools — we’ll train you on those. What we do require is that code doesn’t intimidate you, and that the idea of modifying a production website sparks more excitement than anxiety. #### **What will be your mission?** You’ll join our CRO tech team to technically implement digital experiments that improve our clients’ conversion rates. Your role will be pivotal in transforming ideas into real, measurable, and impactful tests. #### **This will be your day-to-day:** * Develop variants for **A/B tests** and personalization experiments in **HTML, CSS, and** * **JavaScript.** * **Manipulate the DOM** to implement UI changes without altering our clients’ source code. * Learn to use tools such as **VWO, Adobe Target, Optimizely, ABTasty, or** * **Convert** (among others). * Propose creative, fast, and functional solutions. Here, ingenuity is valued as much as execution. * Gradually build your own understanding of the digital ecosystem and how users interact with it. REQUIREMENTS #### **Who are we looking for? Someone who matches these skills:** * **Solid proficiency in HTML, CSS, and JavaScript.** Senior-level expertise isn’t required, but you must feel comfortable working with code. * Familiarity with **DOM manipulation** (**getElementById**, **querySelector**, **events**, etc.). * Genuine curiosity about the **CRO world**, web optimization, and experimentation. * A mindset of "I test, measure, and improve." No fear of controlled errors. * Creativity to find unexpected solutions to technical problems under constraints. * Eagerness to learn and grow within a team packed with accumulated experience. * Ability to collaborate and communicate what you’re doing without needing a manual. * **Residence in Madrid or Zaragoza.** #### **Bonus points:** * Hands-on experience (even in personal projects) with any of the testing tools mentioned above. * Interest in digital analytics and understanding the data behind experiments. * English proficiency will help — especially for reading and comprehending technical documentation. #### **Why us, and not others? Here’s what Flat 101 offers you:** * **Real professional development:** personalized career plans, annual evaluations, access to specialized training, and ongoing mentoring to strengthen your skills and help you achieve your goals. * **Flexibility and work-life balance:** intensive schedule from 8 a.m. to 3 p.m. \+ 1 flexible hour in the afternoon; intensive and reduced summer hours (8 a.m. to 3 p.m.); full trust to responsibly manage your time. * **27 working days of vacation:** we believe rest is essential, so we offer 5 extra days beyond the collective agreement. You’ll have full flexibility to choose your vacation dates. * **Flexible work arrangements:** hybrid or on-site. We bet on trust and autonomy to choose the best way to work. * **Top-tier projects:** national and international projects with leading digital clients, where you can apply your talent and continue learning every day. * **Learning and knowledge sharing:** internal and external training, research studies, mentorships, and an open-book culture fostering collective growth. * **A reference and collaborative team:** diversity, mutual support, and proven expertise in CRO, analytics, design, and product. An environment where communication, empathy, and camaraderie are real. * **Diversity and equality:** we champion inclusive and equitable teams proud of their ideas. Flat 101 is an organization committed to equal pay and fair treatment. We believe diversity is a fundamental pillar of pluralism within an organization. * **Culture and DNA:** our daily work is built upon shared values defining who we are and how we work. Collaboration, teamwork, transparency, respect, and flexibility form our foundation. Innovation, continuous improvement, and empathy drive us, creating an environment where communication flows freely, ideas are valued, and people grow. * **Innovation and dissemination:** we create nationally and internationally recognized research studies. Innovation is part of our DNA, so we foster a culture of continuous improvement. We integrate artificial intelligence into our daily work to boost efficiency, creativity, and excellence in every project. * **Unique atmosphere:** close-knit, inclusive, motivating, and imbued with a strong sense of belonging. You’ll work alongside passionate and committed people. * **Extra perks and benefits:** flexible compensation plan (private health insurance, meal vouchers, transport card, childcare assistance), monetary bonuses for recommending talent and potential clients, and event attendance support. We are a people-first company where the entire team is routinely consulted on corporate decisions. We aim to build and consolidate the best possible company — a benchmark professionally, humanely, and ethically… and we’d love to have you on board. Are you in?