Appveyor vs Azure Pipelines: What are the differences?

# Introduction
This Markdown code provides a comparison between Appveyor and Azure Pipelines based on key differences.

1. **Pricing Model**: Appveyor follows a usage-based pricing model where you are charged based on the number of concurrent jobs, while Azure Pipelines offers a free tier for open-source projects and allows for unlimited build minutes with paid plans.
2. **Supported Platforms**: Appveyor primarily focuses on Windows-based applications, while Azure Pipelines provides support for a wider range of platforms including Windows, Linux, and macOS.
3. **Integration with Microsoft Ecosystem**: Azure Pipelines seamlessly integrates with other Microsoft services such as Azure DevOps, GitHub, and Visual Studio, providing a holistic development environment, whereas Appveyor offers integration with Git-based repositories but lacks the depth of integration seen in Azure Pipelines.
4. **Customization and Extensibility**: Azure Pipelines provides extensive customization options through YAML configurations, allowing users to define complex build pipelines, whereas Appveyor offers a more simplified approach with a user-friendly interface for configuring builds.
5. **Community and Support**: Azure Pipelines benefits from a larger user community and extensive documentation, making it easier to find resources and support, whereas Appveyor has a smaller community but provides personalized support for its users.
6. **Deployment Options**: Azure Pipelines offers a wide range of deployment options including Azure, Kubernetes, and third-party services, whereas Appveyor focuses primarily on deployment to cloud services such as Azure and AWS.

In Summary, this Markdown code highlights key differences between Appveyor and Azure Pipelines in terms of pricing, platform support, integration, customization, community support, and deployment options.