Job Summary: Flat 101 is seeking a CRO Junior Developer with curiosity about web optimization and skills in HTML, CSS, and JavaScript to technically implement digital experiments. Key Highlights: 1. Join the CRO tech team for digital experiments 2. Develop A/B test variants and customizations in HTML, CSS, and JavaScript 3. Learn to use testing tools such as VWO, Adobe Target, Optimizely DESCRIPTION At Flat 101, we’ve spent years helping our clients improve their digital results. We run **tests, experiments, 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 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. What we do require is that code doesn’t intimidate you, and that the idea of modifying a live website excites you more than it gives you vertigo. #### **What will your mission be?** You’ll join the CRO tech team to provide technical implementation for digital experiments aimed at improving our clients’ conversion rates. Your role will be key in transforming ideas into real, measurable, impactful tests. #### **Your day-to-day will include:** * Developing **A/B test** variants and personalization experiments in **HTML, CSS, and** * **JavaScript.** * Manipulating the **DOM** to implement UI changes without touching our clients’ source code. * Learning to use tools such as **VWO, Adobe Target, Optimizely, ABTasty, or** * **Convert** (among others). * Proposing creative, fast, and functional solutions—ingenuity is valued here as much as execution. * Gradually building 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 command of HTML, CSS, and JavaScript.** You don’t need to be senior-level, 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 "test, measure, improve"—no fear of controlled failure. * Creativity to find unexpected solutions to technical problems under constraints. * Eagerness to learn and grow within a highly experienced team. * Ability to collaborate and communicate clearly about your work—without needing a manual. * **Residency in Madrid or Zaragoza.** #### **Bonus points if you have:** * 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—it will help, especially when 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 strengths 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; summer intensive & reduced 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 fully onsite. We bet on trust and autonomy to choose the best way to work. * **Top-tier projects:** national and international assignments with leading digital clients where you can apply your talent and keep learning every day. * **Learning and shared knowledge:** 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 committed to equal pay and treatment. We believe diversity is a fundamental pillar of pluralism in any organization. * **Culture and DNA:** our daily work is built on 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 across all projects. * **A unique atmosphere:** close-knit, inclusive, motivating, and rooted in belonging. You’ll work alongside passionate, committed people. * **Extra perks and benefits:** flexible compensation plan (private health insurance, meal vouchers, transport card, childcare), monetary bonuses for recommending talent and potential clients, and event attendance support. We’re a people-first company where the entire team is routinely consulted on corporate decision-making. We aim to build and consolidate the best possible company—and become a benchmark professionally, humanely, and ethically… and we’d love to have you on board. Are you in?