Define and document API specifications, endpoints, data models, and protocols - REST, GraphQL. Build and implement APIs using programming languages and frameworks such as Java, Python. Ensure seamless integration of APIs with internal and external systems, applications, and third-party services. Write unit, integration, and end-to-end tests for APIs. Debug and resolve issues to ensure reliability and performance. Create and maintain clear, comprehensive documentation for API consumers, including usage examples and best practices. Implement authentication, authorization, encryption, and other security best practices to protect data and services. Monitor and optimize API performance, scalability, and reliability. Manage API versions and ensure backward compatibility as APIs evolve. Work closely with front-end and back-end developers, architects, QA engineers, and other stakeholders to deliver robust solutions. Provide ongoing support, troubleshoot issues, and implement enhancements based on user feedback.