Mac OS X Softwares to Built-in Calendar

Visto is a versatile collective task dashboard designed to streamline project management, team collaboration, and workflow automation. It offers a central platform for managing tasks, tracking progress, and improving team efficiency across various business processes.

todoyu is a comprehensive web-based collaboration and project management solution designed for teams and businesses of all sizes. It integrates essential tools like task management, time tracking, resource planning, a shared calendar, and client interaction features into a single platform.

Open365 is a comprehensive, open-source productivity suite offering cloud storage, office applications, and communication tools. Built upon a foundation of open-source technologies like KDE, Seafile, and LibreOffice, it provides a robust alternative to proprietary solutions, emphasizing privacy and control.

Nylas Mail, an extensible open-source email client, offers a unified inbox, robust search, and calendar integration. It supports multiple accounts and provides features like email tracking and undo send, aiming to enhance productivity and email management for users.

Day One is a popular journaling application available on macOS, iOS, and Android. It provides a simple and elegant interface for capturing daily thoughts, experiences, and memories with rich media support.

Buffer is a comprehensive social media management platform designed to help individuals and businesses schedule posts, analyze performance, and engage with their audience across various social networks.

Apple Calendar is a personal calendar application developed by Apple Inc., designed to seamlessly integrate with your Apple ecosystem whether you are on macOS or iOS. It allows you to manage your schedule, appointments, and events efficiently, synchronizing across all your devices.

Lightning is a comprehensive calendar and task management add-on for Mozilla Thunderbird and Seamonkey, designed to integrate seamlessly with email. It offers robust features for scheduling, task tracking, and synchronization with various online calendar services, enhancing productivity directly within your email client.

Microsoft Outlook is a comprehensive personal information manager designed for managing email, contacts, calendars, and tasks.