An Apache Crunch developer designs, develops, and implements large-scale data processing systems using Apache Crunch framework. They handle complex data types, write data pipelines, and manage distributed computations over Hadoop's MapReduce model. They deal with issues of data serialization and deserialization, ensuring efficient data processing. They also debug and optimize code to improve performance and scalability. Their role involves a strong understanding of data structures and algorithms. They are responsible for maintaining coding standards and participating in code reviews. They work closely with data engineers, data scientists and other stakeholders to understand and meet data requirements.