--- title: "Nylas vs Cronofy vs Google Calendar API: Which Fits Your App" author: "Nate Laquis" author_role: "Founder & CEO" date: "2026-11-02" category: "Technology" tags: - Nylas vs Cronofy - calendar API - Google Calendar API - calendar sync for startups - unified calendar API excerpt: "Use the Google Calendar API directly if your users all live in Google Workspace. Pick Nylas when you need Google, Microsoft and email in one integration, and Cronofy when scheduling is the product and you sell to larger teams." reading_time: "10 min read" canonical_url: "https://kanopylabs.com/blog/nylas-vs-cronofy-vs-google-calendar-api-for-startups" --- # Nylas vs Cronofy vs Google Calendar API: Which Fits Your App ## The short answer: pick by who your users are If every user of your app lives in Google Workspace, call the Google Calendar API directly and skip the vendor. If your users split across Google, Outlook and Exchange, pick Nylas, because one integration covers all of them and it also handles email if you need it later. If scheduling is the core of your product and you sell to larger companies, pick Cronofy, which is built for exactly that and prices like it. That is the whole decision for most founders. The rest of this post is the detail that changes the answer: what a direct integration really costs you in maintenance, how the two vendors charge, and the point where paying a vendor starts to look cheap. ![Wall calendar and planner on a desk representing calendar sync between apps](https://images.unsplash.com/photo-1506784983877-45594efa4cbe?w=800&q=80) One note before the comparison. Vendor pricing in this category moves often and some of it is quote-based, so every number below is a loose range. Confirm current rates on each vendor's pricing page before you budget. ## What you are actually buying A calendar integration sounds like one feature. Read events, write events, show free and busy time. In practice it is four jobs, and a vendor takes some or all of them off your plate. - **Authentication.** OAuth flows for each provider, token storage, refresh, and the case where a user revokes access at 2 a.m. and your sync job starts throwing errors. - **Normalization.** Google, Microsoft 365, Exchange on premises, iCloud and generic CalDAV all model events a little differently. Recurrence rules, attendee states, conference links and all-day events are where the differences hide. - **Change detection.** Knowing when an event changed without polling every account every minute. That means push notifications, renewal of those subscriptions, and a fallback when a notification is dropped. - **Compliance.** Google reviews apps that request sensitive calendar and email scopes. Microsoft has its own admin consent rules for business tenants. The Google Calendar API and Microsoft Graph give you the raw endpoints. Nylas and Cronofy give you one API in front of them. The difference is who carries the maintenance, and how much of it you want to own. ## Google Calendar API directly: free, with a catch The Google Calendar API itself costs nothing at normal startup volumes. You pay in engineering time, and the biggest line item is not the code. It is the review process. Calendar scopes that read or write a user's events are classed as sensitive by Google. If your app asks for them from users outside your own organization, you go through OAuth app verification: a verified domain, a privacy policy that matches how you use the data, a demo video of the consent flow and written justification for each scope. Plan on several weeks the first time, and budget for rejections that ask for small changes. Mail scopes are stricter still, they are classed as restricted and can require a paid third-party security assessment. If your roadmap includes reading email, that cost belongs in the plan from day one. Then comes the ongoing work. Google pushes changes through watch channels that expire, so you need a job that renews them before they lapse and a reconciliation pass that catches anything missed. Sync tokens can be invalidated, which means your code needs a full resync path that does not duplicate events. Recurring events with exceptions, edited single instances and timezone changes across daylight saving boundaries produce the bugs users actually notice: the meeting that shows an hour early for three weeks every spring. A competent developer ships a working one-way read of Google Calendar in about a week. A production-grade two-way sync with renewal, resync, error handling and a verified OAuth app is more like four to eight weeks of work spread over a quarter, mostly waiting on review and then fixing edge cases. ![Developers reviewing calendar sync code together at a shared desk](https://images.unsplash.com/photo-1522071820081-009f0129c71c?w=800&q=80) ## Microsoft Graph directly: the second integration costs more than the first Founders tend to assume Outlook is the same work as Google with different names. It is not. Microsoft Graph uses subscriptions for change notifications, and calendar subscriptions have short maximum lifetimes, so renewal is a hard requirement rather than a nice-to-have. Delivery goes to a public endpoint you must validate, and your handler has to answer quickly or Microsoft will throttle and eventually drop the subscription. Business tenants add another wrinkle. A company IT admin can block user consent, which means your first enterprise customer may need an admin to approve your app before a single employee can connect. That is a sales conversation as much as a technical one, and you want an answer ready: a clear permissions list, a security page and a named contact. Exchange on premises is a separate world again. If a customer runs it, direct integration means either a different protocol or telling them you do not support it. Many B2B apps lose a deal over this exact question. The honest estimate: add three to six weeks for Microsoft on top of Google, and expect to keep fixing small differences in how the two represent recurring events. This is the main argument for a unified API. Each extra provider multiplies the maintenance instead of adding to it. ## Nylas: one API for calendars, email and contacts Nylas sells a unified API across Google, Microsoft, iCloud, Exchange and IMAP accounts. You send your user through its connect flow, and you get back a grant you can use to read and write calendars, and email too if you need it. Its Google and Microsoft apps are verified, which can spare you the Google review for the common case, though you should check the current terms for your scopes and whether you can use your own branded app instead. Nylas also changed its packaging recently. Its September 2026 changelog introduced Nylas Connect as the name for the core platform, with the pricing page now listing Free, Essentials, Pro and Enterprise plans. Older third-party pricing guides still describe a per-connected-account structure with separate rates for calendar only and for the full platform, so numbers you find in comparison posts may be stale. Treat the vendor pricing page as the only source and expect usage to be measured in connected accounts. Where Nylas fits best: - You need Google and Microsoft from week one, and you cannot afford two separate integrations. - Your product touches email as well as calendars, for example a CRM that logs meetings and threads together. - You want to be live in weeks, with a small team, and you will revisit the build-versus-buy question when you have revenue. Where it hurts: cost per connected account matters when users are low-value. A free consumer app that connects a calendar for every signup will find the bill grows faster than revenue. Run the numbers against your expected paying users, not total signups. ![Team reviewing pricing tiers and usage charts on a laptop and printed reports](https://images.unsplash.com/photo-1454165804606-c3d57bc86b40?w=800&q=80) ## Cronofy: built for scheduling products and enterprise buyers Cronofy focuses on calendar connectivity for scheduling and workforce products. Its strengths are in the details a scheduling product needs: reliable availability queries across many calendars, real-time scheduling, smart invites and conferencing links, plus enterprise features like admin-level connection through domain-wide delegation, so a company can connect every employee's calendar without each person clicking through consent. That last feature is the reason many B2B scheduling vendors choose it. A recruiting platform, a healthcare booking product or a field service tool selling to a company with thousands of staff does not want to ask each person to authorize. The admin does it once. Pricing is where you have to talk to someone. Third-party sources disagree on the numbers because Cronofy's production pricing is tiered by volume and largely quote-based, with a developer tier for testing. Expect a flat monthly platform fee that starts in the hundreds of dollars and climbs with the number of synced accounts, with overage beyond the tier. That shape is the opposite of per-account pricing. It is expensive for a small app and comparatively cheap as accounts grow, which is why the crossover point is the number to estimate before you choose. Cronofy does not try to be an email API. If you need to read and send mail, you will pair it with something else or choose Nylas. ## Cost and build time side by side Here is how the three compare for a team of one to three developers. Engineering weeks are estimates for a production-ready two-way calendar sync with Google and Microsoft, not a prototype. - **Direct APIs (Google plus Microsoft):** no vendor fee, roughly 8 to 14 weeks of engineering including OAuth review, renewal jobs, resync and edge cases. Ongoing maintenance of a few hours a week once stable, with spikes when providers change behavior. - **Nylas:** a plan fee that scales with connected accounts, roughly 2 to 4 weeks to integrate. Maintenance mostly shifts to monitoring and handling grant errors when users disconnect. - **Cronofy:** a larger flat fee that rises with volume, roughly 2 to 5 weeks to integrate, depending on how much of its scheduling and availability tooling you adopt. The vendor fee is easier to see than your own salary cost. Eight extra weeks of a senior developer's time costs more than a year of a small vendor plan in most markets. The picture flips at scale. Once you have thousands of connected accounts and a team that already understands the edge cases, a direct build can be worth it for margin reasons. Plenty of companies start on a vendor and bring the integration in house later, once the product is proven and the volume justifies a dedicated engineer. If you are still working out what the whole scheduling product costs, our guide to [what it costs to build an AI scheduling assistant](/blog/how-much-does-it-cost-to-build-an-ai-scheduling-assistant) puts the calendar layer in context next to the rest of the budget. ## The problems every option shares Whichever you pick, a few problems stay yours. Know them before you commit. **Timezones and recurrence.** A vendor normalizes the data. It does not stop you from storing a meeting as a fixed UTC time when the user meant nine in the morning local time every Monday. Store the rule and the zone, not just the resulting instant. **Double booking.** Two users book the same slot a second apart. Your database needs a constraint or a lock, because a calendar write is not a transaction. Check availability, hold the slot, write the event, then confirm. **Disconnected accounts.** Users change passwords, leave companies and revoke access. Build a clear reconnect state in the UI and an email that tells them why their bookings stopped syncing. Every option fails here without that. **Rate limits.** Providers throttle. A vendor smooths some of this out, but a bulk import for a new customer with 500 users can still hit limits. Queue the work and back off. For a wider look at how a scheduling product fits together, including availability rules, buffers and reminders, see [how to build a scheduling app](/blog/how-to-build-a-scheduling-app). And if what you want is a finished booking page rather than an API, [Cal.com vs Calendly vs SavvyCal](/blog/cal-com-vs-calendly-vs-savvycal) covers buying instead of building. ## Which one for your product Map your product to the closest situation below. - **An internal tool or a Google Workspace add-on, all users on Google:** Google Calendar API directly. The verification step is lighter when your users are inside one organization, and you avoid a vendor fee for no benefit. - **A consumer booking app where users connect a calendar to avoid double bookings:** start with the direct Google API if most of your audience is on Gmail, and add Microsoft later. If Outlook users are a large share on day one, use Nylas and watch the cost per connected account. - **A B2B CRM or sales tool that logs meetings and email threads:** Nylas. You get email and calendar in one grant, and Microsoft support comes included. - **A scheduling product for recruiters, clinics or field teams sold to companies:** Cronofy. Admin-level connection and availability tooling matter more than a low entry price. - **A prototype to test demand:** Nylas on a starter plan, or the direct Google API for one provider. Do not spend ten weeks on sync before you know anyone wants the product. - **A very large consumer base with thin margins per user:** plan to build direct eventually. Per-account pricing will hurt, so start on a vendor and set a trigger for the switch, such as a monthly bill that equals one engineer's time. Kanopy helps founders pick a stack like this and build the product on it, so the calendar layer is decided with the rest of the architecture instead of bolted on after launch. ## How to decide this week Write down three numbers. First, the share of your expected users on Google, Microsoft and anything else. Second, how many connected calendars you expect at 6 months and at 24 months. Third, what one developer-week costs you. With those, the comparison takes an afternoon. If Microsoft users are under 10 percent and you are early, go direct with Google and revisit later. If they are over 30 percent, price a vendor. If you sell into companies and each deal has hundreds of seats, ask Cronofy for a quote and ask Nylas what an enterprise plan looks like, then compare them against your direct-build estimate rather than against each other. Whatever you choose, wrap it behind your own interface from the start. A small internal calendar service with methods like list events, create event and watch changes means swapping providers later touches one module instead of the whole app. It is a day of extra work now and it saves a rewrite if pricing or needs change. If you want help scoping that, [Book a free strategy call](/get-started). --- *Originally published on [Kanopy Labs](https://kanopylabs.com/blog/nylas-vs-cronofy-vs-google-calendar-api-for-startups)*