Calendar APIs allow businesses to integrate applications with calendars across service providers, such as Microsoft Outlook and Google Calendar. Without calendar APIs, manually building scheduling connectivities within an app or website exhausts resources and time.
Using calendar APIs means development teams can focus on building mission-critical features that maximize adoption and retention. Businesses can save time while increasing scheduling productivity for their end users and easily capture valuable insights.
But determining which calendar API will best optimize your scheduling workflows can be difficult. So today, we’ll cover the best calendar APIs on the market so you can find the right one for your business.
What is a calendar API?A calendar API allows developers to integrate calendar functionality into their applications and websites. With the help of calendar APIs, developers can easily centralize scheduling workflows within a platform, enabling users to create and manage calendar events, invite attendees, sync calendars, set reminders, and more.
However, not all calendar APIs are created equal. Well-designed calendar solutions for embedding scheduling capabilities in an application or website should offer a wide range of customization options to fit unique business needs.
But many calendar APIs are missing crucial capabilities that can roadblock your integration efforts. For example, while some calendar APIs offer a free/busy resource showing a single user’s availability, you may not be able to compare the availability of multiple individuals easily.
Similarly, if you want to find availability for multiple meetings with several participants, without the right calendar solution, this functionality can require additional development effort and custom code.
To avoid spending invaluable developer time and resources, you’ll want to opt for a calendar API that offers availability endpoints. Doing so will allow users to see shared availability across multiple parties, both internal and external, to an organization. And consecutive availability endpoints provide time slots across participants for multiple, consecutive meetings.
Availability is just one example of features you may be looking for out of a calendar API. When looking for the best calendar solution, it’s important to consider the needs of your users.
Below we’ve outlined the top calendar APIs on the market, highlighting how they work, key features, and pricing structures to help you determine the best fit for your organization.
Best calendar APIs1. Nylas Calendar APIHow it works: The Nylas Calendar API is the best solution for developers to connect their applications to all major calendar providers using a single point of integration. It provides developers the flexibility to quickly and securely build integrations and customize workflows for your users, offering an end-to-end scheduling solution. By helping users automate their scheduling workflows, the Nylas Calendar API creates a seamless user experience in your app which can increase retention and CSAT.
The Nylas platform goes beyond calendar connectivity and scheduling with a powerful suite of communications integration solutions, including email and contacts APIs.
Key features:
Availability endpoints: Remove the back-and-forth with automated scheduling based on free/busy availability Customizable workflows: Configure scheduling workflows with custom integrations and build native experiencesEliminates siloed data: Capture calendar data in applications and unlock valuable insights to build automated user workflowsAutomated reminders: Send alerts and notifications for upcoming events across email, Slack, and Microsoft TeamsVirtual calendars: Schedule events for people and objects or resources that aren’t associated with an existing calendar accountService accounts: Utilize service accounts for companies that need instant onboarding within organizationsCustomizable scheduling UI: Tailor scheduling tools with a design unique to your businessPricing:
Nylas offers a full-service API platform, including an email API, calendar API with a front-end scheduler, and contacts API. Pricing plans vary by the number of connected accounts (end users).
Talk to an expert today to choose the best plan for your business.
2. Cronofy Calendar APIHow it works: Cronofy’s calendar API allows developers to connect their applications with multiple calendar service providers, such as Google Calendar and Apple Calendar. The API provides developers with guides and SDKs to assist them in navigating the platform. One of the key features of the Cronofy Calendar API is its real-time availability, which helps users avoid scheduling conflicts.
The API also includes UI elements that can be embedded into an application and the ability to send out calendar invites with video conferencing details.
Key features:
Enables users to build scheduling features into calendarsEnables users to build real-time, two-way sync across calendarsFull create, read, update, delete (CRUD) operations that allow Cronofy to read and delete individual events, on behalf of the user, created by the APIPricing:
Cronofy offers annual and monthly pricing packages for their API and scheduler separately.
Cronofy API (Annual plan) Starter: $119 per monthEmerging: $739 per monthGrowth: $2,149 per monthCronofy API(Monthly plan) Starter: $139 per monthEmerging: $819 per monthGrowth: $2,399 per monthStrategic: Customizable plan. Contact Cronofy for a quote.Scheduler (Annual plan) Business: $709 per monthEnterprise: $2,689 per monthScheduler (Monthly plan)PAYG: $15 per monthBusiness: $799 per monthEnterprise: $2,999 per month3. Calendly APIHow it works: Calendly enables users to automate appointment and meeting scheduling. It offers a REST-based API that allows businesses to retrieve Calendly links, report on scheduled meetings, and retrieve availability for a specific event type for team members within an organization. The platform also has an Embed API, which lets businesses add a user’s Calendly scheduling page to their websites by enabling inline, pop-up text, or pop-up widget variations.
Calendly’s API is read-only, intended to make it easier for businesses to embed calendar functionality on web pages. For example, it can only read the free/busy status of events in users’ calendars. For organizations looking to extract scheduling data, you’ll want to consider an API that uses event metadata to drive deeper insights.
Key features:
Automates event scheduling, canceling, and rescheduling via webhooks Enables users to embed Calendly API via OAuth or personal access tokensAdmins can report on events and access information about event typesPricing:
Calendly is primarily feature-based and offers four pricing models:
Basic: FreeStandard: $10 per user per month (annually) | or $12 per user per month (monthly)Teams: $16 per user per month (annually) | or $20 per user per month (monthly)Enterprise: Custom quote basis4. Google Calendar APIHow it works: The Google Calendar API allows for the creation, reading, updating, and deletion of calendar events, as well as the management of calendar settings and the reading of calendar metadata. The API helps handle single or recurring events, calendar management, user preferences, and access control rules.
Google’s calendar API follows RESTful principles and can be accessed via explicit HTTP calls or through the use of Google Client Libraries. The API uses OAuth 2.0 for authentication and supports multiple programming languages.
Key features:
Enables users to add events, including recurring eventsUsers can specify and manage a working locations where others can view before invitation to an eventPush notifications to inform users of changes Provides extended properties which enables users to store data without an external databasePricing:
As a support tool, Google Calendar is free to use. However, it doesn’t have as many features or capabilities as other paid options, like Nylas.
5. Zoho Calendar APIHow it works: Zoho Calendar is a calendar and scheduling platform that is part of the Zoho suite of productivity and collaboration tools. The platform brings all calendars to one place and enables organizations to collaborate and manage events, appointments, and bookings. The Zoho Calendar API enables developers to customize features in the Zoho Calendar, and integrate the calendar with your application.
Key features:
Developers can edit, delete and add an existing calendar Users to share calendar details and get details of file attached to a created eventEnables users to update and move an event from one calendar to anotherPricing:
While Zoho Calendar is free, pricing for the Zoho Calendar API is not listed online.
6. AddEvent APIHow it works: AddEvent is a platform that enables developers to add events to users’ calendars, collect information from attendees during registration, share multiple events through a subscribable calendar, and embed a calendar on a website.
AddEvent offers both a calendar API and an event API. The calendar API makes it easy for end-users to create, save, and delete calendars, view and delete subscribers, create, save, and delete events, and list all events across all calendars. The event APIs also allow users to create, save, and delete events, as well as manage RSVPs, list events, and manage time zones.
Key features:
List, create, view, edit, delete and share an eventSetting events according to timezones List, view, create and save details about an event RSVP and attendeesPricing:
AddEvent offers four annual pricing plans:
Hobby: Free for personal use only (limited functionality) Small business: $36 per month | or $29 per month (billed annually) Professional: $159 per month | or $119 per month (billed annually) Enterprise: Contact AddEvent for pricing 7. Timekit APIHow it works: Timekit’s API allows developers to create resources, sync calendars, manage projects, and control booking flows. Users can customize their interface and manage bookings through their booking.js kit, which contains various blueprints. The Timekit API also utilizes webhooks for their booking process, which provides users with a real-time view of changes that happen to a booking.
Key features:
Allows users add customizations to timekit calendar or other external calendars Provides booking infrastructure for businesses Provides webhooks for data integration Allows users to create resources and confirm resource availabilityPricing:
Timekit offers four pricing levels:
Essential: $49/moProfessional: $149/moPlatform: $349/moEnterprise: Contact Timekit for more information8. Cal.com APIHow it works: The Cal.com API provides access to data models that allow developers to build calendar features into their own applications, including availability displays and specific event mapping. The API allows users to manage teams on self-hosted platforms.
Key features:
CRUD bookings and events typesDevelopers can manage user endpoints on self-host enterprisesTrack the charges required to book some eventsMembers can map users to a particular team rolePricing:
Cal.com offers four pricing categories:
Free: $0.00/mo/user, ideal for individual consumersTeams: $15/mo/user Organizations: $37/mo/userPlatform: Starts at $99/month9. Outlook Calendar APIHow it works: The Microsoft Outlook Calendar API is a solution that caters to personal, educational, and business services. It’s linked with Outlook email services and helps users integrate and manage calendar events and appointments.
The Outlook Calendar API is synced with other Microsoft 365 products and enables access to phones and email contacts, as well as OneDrive.
Key features:
Create, manage and respond to events Track changes to an event and decline or accept a meeting Share a calendar and delegate a calendar to another user Book meetings at convenient times by enabling free/busy availability check Schedule recurring eventsPricing:
Microsoft Outlook calendar API is free for personal use but offers a subscription-based model for the business and education sectors.
Summary of top calendar APIsAre you looking to further narrow down your options? We’ve categorized the top calendar APIs by integrations below.
Calendar APIs that connect with Google calendarsNylas Calendly AddeventTimekitZohoCronofyCalendar APIs that connect with Apple calendarsNylas Calendly CronofyZoho CalendarAddeventZohoCalendar APIs that connect with Microsoft Outlook calendarsNylasTimekitCalendlyAddeventZohoCronofyUse the best calendar APIThe best calendar API is going to depend on what your business is looking for. If you need to quickly add scheduling and other calendar capabilities to your business application – while saving your developers thousands of hours of building time – Nylas is the top choice.
Try out the Nylas Calendar API today and revolutionize how you get things done.