How to Build Calendar Scheduling Across Google, Outlook, and 15+ Platforms with a Unified API

November 1, 2025

Every SaaS product that handles meetings, onboarding, interviews, or demos eventually needs calendar scheduling. The problem: every calendar platform—Google Calendar, Microsoft Outlook, Cal.com, and Calendly—uses different authentication models, schemas, and conferencing APIs.

A unified API removes that complexity. Unified.to lets your product offer scheduling, free-busy lookup, and one-click event creation across 19+ calendar and conferencing platforms. You can even embed a front-end scheduling component that delivers the same seamless experience users expect from tools like Calendly—without building per-vendor integrations.

When to Use Calendar Scheduling

With a unified API, you can:

Offer Calendly-like booking directly inside your product
Find mutual availability and free times across participants via normalized free-busy data
Create events with auto-generated conferencing links and attendee invites
Handle updates, cancellations, and reschedules in real time

Normalized Calendar Objects

Unified.to provides a consistent schema for all major calendar and conferencing providers:

Object	Description	Key Fields
calendar	A user or resource calendar	`id`, `name`, `timezone`, `owner_id`
freebusy	Availability over a given time window	`start_at`, `end_at`, `busy[] (start_at, end_at)`, `time_zone`
event	Meeting with participants and conferencing	`id`, `title`, `start_at`, `end_at`, `attendees[] (email, response_status)`, `conference (provider, join_url, meeting_id)`, `location`, `description`, `status`
recording	Video meeting recording and transcript	`start_at`, `end_at`, `attendees`, `language`, `transcript`, `recording_download_url`
webhook	Real-time event change delivery	`object_type`, `event`, `type`, `sig`, `nonce`

Data Flow for Calendar Scheduling

Unified standardizes the entire scheduling flow across providers:

Connect your customer's calendar (and conferencing tool if separate) via Unified.
Query free/busy data for one or more participants across a target window.
Select an available slot (applying buffers, work hours, or location rules).
Create an event with attendees[] and conference.provider; Unified returns the join_url and delivers invites automatically.
Subscribe to webhooks for updates or cancellations to keep your UI and reminders in sync.

This workflow makes it simple to deliver real-time scheduling and conferencing in your own product experience.

Supported Calendar & Conferencing Platforms

Unified.to supports 19+ calendar and conferencing platforms, including:

Google Calendar, Microsoft Outlook/Teams, Apple iCloud, Cal.com, Calendly, Google Meet, Microsoft Teams, and Zoom.

See the full list of supported Calendar integrations or review the Calendar API documentation for implementation details.

Why Product Teams Choose Unified.to

For PMs and engineers building scheduling or booking functionality:

One API, all calendars — unify scheduling across 19+ platforms
Built-in conferencing — auto-generate Google Meet, Teams, or Zoom links
Real-time sync — webhook-driven updates for events and availability
Calendly-like UX — optional embedded scheduling component

Deliver frictionless scheduling directly inside your product.

Start your free 30-day trial or book a demo to see how Unified.to accelerates your roadmap.

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