Bazel vs Gradle vs Pants: What are the differences?

1. Build Tool Purpose: Bazel is designed for large, complex projects with a focus on performance and reproducibility, while Gradle is more popular for its flexibility and ease of use in smaller projects. Pants, on the other hand, focuses on build automation and dependency management for diverse software projects.
2. Language Support: Bazel primarily supports Java, C++, and Python languages with limited support for others, whereas Gradle has a wide range of language compatibility, including Java, C++, Groovy, and more. Pants offers support for several languages such as Java, Python, Scala, and more, making it versatile in language support.
3. Build Caching: Bazel emphasizes build caching to improve build times and reduce redundant work, ensuring faster and more efficient builds. Gradle also offers build caching capabilities, but it may not be as fine-tuned and optimized as Bazel. Pants, on the other hand, focuses on task isolation and smart caching strategies to enhance build performance.
4. Community and Ecosystem: Gradle has a vast community and ecosystem with extensive plugin support and documentation, making it easier for developers to find solutions and resources. Bazel also has a supportive community but may not have as large of an ecosystem as Gradle. Pants is gaining traction in the build tool space but may have a smaller community and fewer available plugins compared to Gradle and Bazel.
5. Configuration and Extensibility: Bazel uses a declarative configuration language, BUILD files, which can be restrictive but offer strict dependency management. Gradle provides a more flexible and customizable configuration using Groovy or Kotlin scripts, allowing for easier extensibility. Pants uses a combination of Python-based configuration and BUILD files, offering a balance between flexibility and manageability in build configurations.
6. Corporate Backing: Bazel is developed and maintained by Google, emphasizing its focus on scalability, performance, and reproducibility for massive projects. Gradle is supported by Gradle Inc, providing commercial services and enterprise support, ensuring stability and reliability for businesses. Pants, originally developed by Twitter, has gained support from other companies like Foursquare and Square, offering a collaborative approach to build automation and innovation.

In Summary, the key differences between Bazel, Gradle, and Pants lie in their build tool purposes, language support, build caching strategies, community ecosystems, configuration styles, and corporate backing.