Junior JavaScript Developer

Are you passionate about JavaScript development, integrations, and solving complex technical challenges in customer-facing environments? We are looking for a Junior JavaScript Developer to join a dynamic AdTech project focused on behavioral analytics and marketing automation. At Sigma Software, you will work on scalable integrations connecting websites, marketing platforms, and real-time customer engagement systems. This role combines Front-end development, API integrations, troubleshooting, and collaboration with international teams. We as a company offer a supportive engineering culture, opportunities for professional growth, and the chance to work with modern AdTech and marketing automation technologies while contributing directly to customer success. CUSTOMER Our partner is a fast-growing AdTech company helping brands identify and engage anonymous website visitors through behavioral intelligence and marketing automation. The platform transforms browsing behavior into actionable insights, enabling personalized campaigns across email, SMS, and paid advertising channels. The solution supports businesses in improving conversion rates, customer engagement, and revenue growth through scalable data-driven marketing strategies. PROJECT The project focuses on developing and maintaining integrations between the AdTech platform and customer ecosystems, including websites, Email Service Providers, and marketing automation tools. The team delivers behavioral tracking solutions, onboarding processes, real-time event pipelines, and personalized onsite experiences for international customers. You will participate in integration development, technical troubleshooting, migration activities, and implementation of custom JavaScript solutions for marketing campaigns and data synchronization workflows. Configure and maintain website integrations, including event tracking, SPA fixes, cart tracking, and catalog integrations Implement and support Email Service Provider integrations and synchronization workflows Execute migration and replatforming activities with comprehensive validation and testing Develop custom onsite JavaScript solutions for campaigns and interactive user flows Build and support Airflow DAGs for recurring data processing workflows Configure dynamic email content and SKU-level recommendation tracking Analyze Customer requests and assess technical feasibility of solutions Develop integrations with third-party marketing and email platforms Investigate and resolve production issues and perform root cause analysis Collaborate with account managers, QA engineers, and implementation specialists Participate in technical consultations and onboarding alignment meetings 2+ years of commercial experience with Vanilla JavaScript (ECMAScript 5+) Strong knowledge of HTML and CSS Hands-on experience with REST API integrations Practical experience with jQuery Experience with Chrome DevTools and browser debugging Understanding of behavioral event tracking implementation Knowledge of Email Service Provider integration workflows Ability to develop custom JavaScript logic for onsite experiences Strong analytical and problem-solving skills Good communication skills with technical and non-technical stakeholders Attention to detail and commitment to code quality Experience working in cross-functional teams Intermediate+ English level Readiness to learn new tools and domain-specific technologies WILL BE A PLUS Experience with PHP Familiarity with Apache Airflow Experience using Postman Understanding of Git workflows Experience with AdTech or marketing technology platforms Exposure to Customer-facing onboarding or integration projects PERSONAL PROFILE Proactive and solution-oriented mindset Strong ownership and accountability Ability to work independently and collaboratively Detail-oriented approach to testing and troubleshooting Comfortable working in a fast-paced environment Strong communication and stakeholder management skills