To thrive as a Junior Developer at a startup, you need foundational knowledge of programming languages (such as JavaScript, Python, or Ruby), basic understanding of web development, and a degree in computer science or related experience. Familiarity with source control systems like Git, cloud services, and popular frameworks is important, and participation in coding bootcamps or relevant certifications is a plus. Strong problem-solving, adaptability, and effective communication are key soft skills for collaborating in a dynamic, fast-paced environment. These abilities help junior developers quickly learn, contribute to product development, and grow within the rapidly evolving startup landscape.