11 Most Popular Calendars APIs

Synching up events and appointments onto a calendar can be an arduous task. Luckily there are some handy programmatic tools, such as APIs, to help developers create and enhance calendar applications.

What is a Calendars API?

A Calendars API is an Application Programming Interface that enables developers to access and integrate Calendars functions and data with their own applications.

The best place to seek out these APIs is in the Calendars category of the ProgrammableWeb API directory. In this article, we give details about the ten most popular Calendars APIs according to website visits.

1. AppointmentPlus API

AppointmentPlus is an online reservation software provider. Business can embed AppointmentPlus links onto their websites or use AppointmentPlus as a standalone booking service as their website. It also provides POS functions for businesses to accept payment through the appointment-making interface. Their RESTful AppointmentPlus APITrack this API provides functionality for integrating scheduling making software, and replies in JSON and XML formats.

2. Google Calendar API

The Google Calendar Data APITrack this API lets users perform most of the operations available on the Google Calendar website and incorporate Google Calendar functionality into their own application or website. Users can edit calendars, create and delete events, query for events that match particular criteria, send invitations, and more. Users can create a web front end for a group calendar that uses Google Calendar as a back end, or a public event calendar can be generated for Google Calendar to display. Also, users can search relevant calendars to display a list of upcoming events on those calendars, and more.

Find and view public events with Google Calendar API

Find and view public events with Google Calendar API. Screenshot Google

3. Sunrise and Sunset Times API

Sunrise-Sunset is a free online service that provides users with information on day length, twilight, sunrise times, and sunset times for any date and location in the world. The Sunrise Sunset Times APITrack this API allows users to retrieve exact sunrise and sunset times for a given latitude and longitude, and if wanted, a specified date.

4. Eventful API

Eventful is a digital media company and entertainment discovery service that helps consumers find sports, music, comedy, performing arts and many other types of local events. The Eventful APITrack this API allows developers to integrate Eventful Platform capabilities and data with third-party applications. The company provides a basic API site for developers with well-organized Documentation, client libraries, search tutorial and other developer tools.

5. Days of the Year API

Days of the Year service provides a calendar to browse weird, funny, wonderful, and bizarre holidays celebrated around the world and an APITrack this API to integrate daily, weekly, and monthly happenings in JSON & CSV formats.

Days of the Year API

Screenshot: Days of the Year

6. Microsoft Graph API

Since the Microsoft Outlook REST API was deprecated, developers looking to integrate with Microsoft's calendar service should look to the Microsoft Graph APITrack this API. Microsoft Graph makes it possible for developers and IT professionals to access many of Microsoft's services programmatically, all from one place. The Microsoft Graph API provides unified metadata, Payload format, Error Handling, and SDKs to drive business productivity such as Outlook Mail, Outlook Calendar, contacts, documents, directory, devices and more.

7. OnlyOffice API

ONLYOFFICE is an open-source platform for business collaboration and project management. The platform includes software for calendars, managing projects, collaborating with team members, document management and a CRM. The ONLYOFFICE APITrack this API exposes the functionality of the platform and gives developers programmatic access to it. Users can perform standard CRUD operations on groups, events, schedules, files, projects, forums, people and more.

8. Calendly API

Calendly makes scheduling software for users to provide customer based calendar services by eliminating email and phone tag for scheduling meetings and appointments. The Calendly APITrack this API allows you to integrate a Real-time calendar to schedule your business. Features include Webhooks, and invitee created and canceled event, group events, team scheduling, notifications, scheduling appointments, interviews, calls, demos and more.

9. Holiday API

The Holiday APITrack this API is a Web Service that provides free programmatic information about holidays worldwide. The API returns data based on paramenters such as country, year, month, day, previous, upcoming, public, language, search, format, and pretty, which prettifies results to be more human-readable. There are several SDKs and three pricing tiers available.

10. Festivo API

Festivo aggregates holiday information via Machine Learning technology. The Festivo APITrack this API provides users with data on holidays for more than 240 countries and states around the world. The API returns each holiday's name, date, country, and type as well as upcoming holidays and more. The service offers reliable source of holiday information for payroll administration, stock market trading, banking, trend detection and prediction of sales, along with many other use cases.

11. Nylas API

Nylas provides communication APIs for developers. The Nylas Calendar APITrack this API provides a connection to a user's calendars. With the API, developers can sync historic and live events, get bi-directional calendar sync and full CRUD capabilities with Google Calendar, Exchange Calendar, iCal, and Outlook.com. Manage calendars, search for events, send reminders, and RSVP to events via this API.

Nylas API

Screenshot: Nylas

Check out the Calendars category for more APIs, plus SDKs, Source Code samples and other developer resources.

Be sure to read the next Calendars article: Google Updates Calendar API Rate Limiting Schedule