Here is a neutral, one-paragraph summary of the text: Slack notifications are a popular way to reach business users with time-sensitive alerts or action items while they're at work. To send messages in Slack, software systems must integrate with its API, which offers a conventional HTTP REST API that's easy to understand for developers. Beyond sending messages, other functionality can be implemented using Slack's API, such as slash commands, message editing, and bot interactions. Developers should consider technical aspects like rate limits, attachments, and compliance with regulations when building a Slack integration. To design a helpful notification experience, it's recommended to use Slack status information, create message templates, and handle language preferences and translation workflows. Finally, developers can explore tools like Courier, which offers pre-built integrations for various messaging services, to simplify the process of building strong notification systems.