Pyas vs. building it yourself on the Google Calendar API, Microsoft Graph and Zoom

The core difference

The Google Calendar API, Microsoft Graph and the Zoom API are free to call. What costs time is everything around the calls. Before a user outside your company can connect, each provider wants to review your app. Once they connect, you keep their tokens alive, keep a push channel or subscription open for every calendar, and translate between two different ideas of what an event is.

Pyas is that layer, built once. Your users connect Google, Outlook and Zoom through Pyas Auth, which Google, Microsoft and Zoom have already verified. Your code calls one API for events, free time, meeting links and webhooks, and gets the same shape back from every provider.

What building it yourself involves

Google Calendar

1. A Google Cloud project and OAuth client, with a consent screen, verified domains and a privacy policy.
2. Google's review. Calendar scopes are sensitive. Until Google verifies the app, only 100 new users can ever sign in, each sees "Google hasn't verified this app", and test users' refresh tokens expire after seven days. The review asks for a justification per scope and a demo video. How long it takes: 3 to 10 business days by Google's count, weeks to months by developers' reports.
3. Push notifications. A watch channel per calendar, which expires, and "there's no automatic way to renew a notification channel." Each notification only says something changed, so you sync with a sync token, and start over when it expires with 410 Gone.
4. Meet links, which Google ignores unless the request carries conferenceDataVersion=1. Details in meeting links from an API.
5. Deleted events, which a read returns with status: cancelled instead of a 404.

Outlook and Microsoft 365

1. An app registration in Microsoft Entra, with publisher verification, and code for MSAL's token cache. Our Node.js guide walks through it.
2. Admin consent. Microsoft's default consent setting keeps users from approving calendar access on their own in many work tenants, so they see "Need admin approval".
3. Subscriptions that last at most 10,080 minutes on events, need a validation reply within 10 seconds, and fail without warning when they lapse. "Dropped notifications can't be recovered," so a scheduled sync has to catch what was lost.
4. Windows time zone names, including three Canadian ones the standard mapping lacks, and all-day events stored in UTC.
5. Teams links, which only Microsoft 365 calendars allow. On a personal Outlook.com calendar the event is created with no meeting and no error.

Zoom

1. A Zoom OAuth app and Zoom's Marketplace review: a test plan with test logins, a reason for every scope, your full tech stack, an architecture diagram and a security review against the OWASP Top 10. Until it passes, only people on your own Zoom account can authorize it.
2. Meetings that are not events. You create the meeting, copy its link onto a Google or Outlook event and keep the two in step, within Zoom's limit of 100 creates and updates per user per day.

Then the parts every provider shares

• Tokens: stored encrypted, refreshed, and handled when a user revokes access or Google's limit of live refresh tokens retires an old one.
• Free time across people: Google's freeBusy returns busy intervals for up to 50 calendars, Graph's getSchedule covers up to 20 people and not personal accounts. You merge them in UTC, then apply each person's working hours. See free/busy across Google and Outlook.
• Recurring events: RRULE on Google, recurrence patterns on Graph, and occurrences that change on their own.
• Keeping up: Google's quota and pricing changes, Microsoft retiring EWS in Exchange Online, and a new Zoom review for every new scope.

When building it yourself is the right choice

Your users are all inside your own organization. An app used only by people in your own Google Workspace can use the Internal user type, which skips Google's review, and a single-tenant Entra app is approved once by your own administrator. The hardest part of the work goes away.

You need one provider and one feature. If the product only ever writes events to Google Calendar, one integration with one event model is a reasonable thing to own.

The integration is your product. If you sell calendar infrastructure yourself, owning every layer is the point.

When Pyas is the right choice

Calendars are a feature of your product, not the product. A booking flow, a CRM that logs meetings, an assistant that schedules. Your time goes into the feature, and Pyas covers the Google, Outlook and Zoom layer underneath.

You want users connecting now. Pyas Auth is on every plan, the free one included, so real users can connect while your own Google review would still be in the queue.

Your users are on both Google and Outlook. One event shape, one webhook format, and free time across both in one call, instead of two of everything.

You want to test before anyone connects. Every Pyas app has a sandbox of simulated Google, Outlook and Zoom accounts with real-looking calendars, reached with test keys.

Who handles the reviews

On your own, every review is yours: Google's for calendar scopes, Zoom's for the Marketplace, and Microsoft's publisher verification. Each takes days to weeks, and each comes back if you add a scope.

With Pyas Auth, users approve Pyas on Google's, Microsoft's and Zoom's own consent screens, and the reviews are already done. If you want your own name on the consent screen later, Native Auth switches one provider at a time to your own app, so you can go through a review on your own schedule while your users keep working.

What it costs

The provider APIs have no per-account fee. Google says standard use of the Calendar API "is available at no additional cost" and plans to charge above its quotas later in 2026, with at least 90 days' notice.

The real cost is engineering time: the build, the reviews, and the upkeep that never ends. Pyas's pricing is per connected account: free for 3, $15 a month for 10, $45 for 60, $75 for 200, then $0.25 each. A product with 1,000 connected calendars pays $275 a month.

Questions to ask before you choose

• Will people outside your organization connect? If yes, you need Google's review on your own. With Pyas Auth you don't.
• How many providers? Each one is a separate sign-in, event model and notification system.
• Do you need Zoom links? On your own, that is a Zoom app and Zoom's review. With Pyas, it is one field.
• Who keeps it running? Channels and subscriptions expire every few days, tokens break, and providers change their APIs. Someone owns that every week.
• How soon do you need real users? Count the reviews before your launch date.

Moving from your own integration to Pyas

1. Build against the sandbox. Point your calendar code at Pyas test keys and check reads, writes, recurring events and meeting links on simulated accounts.
2. Keep your own apps if you want. With Native Auth, your Google, Microsoft or Zoom app stays on the consent screen. Or switch to Pyas Auth and retire them.
3. Have users connect once through PyasConnect. Their events stay in Google Calendar and Outlook, so there is nothing to export or import.
4. Replace your push handling. Drop channel renewal, subscription renewal and sync-token storage, and handle Pyas's webhooks, which name the event or calendar that changed.
5. Delete the provider-specific code: time zone mapping, recurrence translation, Meet and Teams request details.

The bottom line

Building it yourself makes sense when your users are all inside your own organization, or when the integration is the product you sell. For everyone else, the provider APIs are the easy part. The reviews, the event models and the notifications that expire are the work, and Pyas has already done it. Start in the sandbox, and connect real users on the free plan the same day.