Jenkinsfile and bitrise.yml are configuration files used to define CI/CD pipelines, with Jenkinsfile using Groovy and bitrise.yml using YAML. Both share similar functionalities such as code-based definition, modular structure, declarative nature, structure and hierarchy, phases, tasks, steps, parallelization, input instructions, and a hierarchical structure. However, their approaches differ in flexibility, simplicity, readability, and customization options. Jenkinsfile offers more granular control through Groovy scripting, making it suitable for complex workflows, while bitrise.yml prioritizes simplicity with a user-friendly YAML syntax, catering to mobile app development workflows and offering built-in integrations for common tools. Ultimately, the choice between Jenkinsfile and bitrise.yml depends on specific needs and preferences, with no clear-cut winner.