M
API Matrix

Google Calendar API

Calendar / OAuth Advanced HTTPS
Varies by plan (check documentation)
68 Score
Grade C
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Overview

The Google Calendar API allows you to programmatically read, create, update, and delete events on any Google Calendar accessible to the authenticated user. It uses OAuth 2.0, making it suitable for apps that act on behalf of real Google accounts. It supports recurring events, reminders, attendee management, and calendar sharing.

💡

Beginner Tip

OAuth 2.0 is the biggest hurdle for beginners. Use the Google OAuth Playground (developers.google.com/oauthplayground) to generate a test token before writing any code, and never hardcode tokens in public repositories.

Available Data

event dates and names
holiday lists by country
date metadata

Example Response

JSON Response 
{
  "id": 1,
  "name": "Google Calendar",
  "data": "Display, create and modify Google calendar events",
  "source": "Google Calendar"
}

Field Reference

items[].id Unique identifier for the calendar event.
items[].summary Title or subject line of the calendar event.
items[].start.dateTime Start time in RFC 3339 format, e.g., "2024-12-25T10:00:00-07:00".
items[].end.dateTime End time in RFC 3339 format.
items[].attendees List of attendee objects each containing email and responseStatus (accepted/declined/tentative).
items[].status Confirmation status of the event: "confirmed", "tentative", or "cancelled".

Implementation Example 

const url = "https://developers.google.com/google-apps/calendar/";
// Replace headers or query params with the values required by this API.
const response = await fetch(url, {
  headers: {
  "Authorization": "Bearer YOUR_API_KEY"
  }
});
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

403 Forbidden: insufficientPermissions OAuth scope does not include calendar write access
✓ Request scope https://www.googleapis.com/auth/calendar for full access, or https://www.googleapis.com/auth/calendar.readonly for read-only.
401 Unauthorized: invalid_token Access token has expired after its 1-hour lifetime
✓ Implement token refresh logic using the refresh_token from the initial OAuth flow instead of asking users to re-authenticate.
404 Not Found on event operations Event ID belongs to a different calendar or account
✓ Event IDs are scoped to a specific calendarId; pass the correct calendarId (e.g., "primary" or the full email address) in the URL path.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 10/20
🔒 Security 15/15
🛠 Developer XP 3/20
✓ Reliability 10/15

Partially tested on Apr 5, 2026

Technical Specifications

Auth OAuth
HTTPS REQUIRED
CORS UNKNOWN
Category Calendar
Difficulty Advanced
Verified: 2026-04-07

Recipes Using Google Calendar

Build something with this API. Each recipe includes step-by-step instructions and code outlines.

Advanced 6-8 hours

Build a Smart Event Planner

3 APIs

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