First decide whether you're building scheduling into your own product or simply need a way for people to book you. Software teams adding calendar features for their users need an API. Businesses that just want clients or colleagues to pick a time are better served by a ready-made booking tool that works on day one.
Build or buy? That's the real question behind most searches for a calendar sync replacement. Cronofy sells calendar sync, scheduling and meeting transcription as building blocks that software companies add to their own products. Some people looking for an alternative want the same building blocks from another supplier. Many others realise they never needed to build anything, and a booking tool would do. This list of nine, in no particular order, covers both.
Infrastructure or a finished booking tool?
The thing to test in any replacement is how invitees pick a time, how calendars sync, and what happens when plans change. That's true whether you're a developer or a business owner, but you test it in very different ways.
If you're building, you're judging an API: how many calendar providers it connects to, how it handles changes made outside your app, and how much of the interface you'll have to build yourself. If you're buying, you're judging the booking page your clients see, and how reliably it keeps your diary clean.
Only one tool on this list is mainly a developer platform. The other eight are booking tools you can use straight away, without writing any code. If you're a small business that landed on an infrastructure product by accident, that's good news: you can be up and running in an afternoon. You won't need a developer, a sandbox or an API key, just a calendar and a list of the times you're happy to be booked.
All nine, A to Z
Alphabetical and unranked. Each line reflects how the vendor describes its own product.
Acuity Scheduling
Best for: Client-facing businesses that want appointment booking with scheduling automation and plenty of room to customise it, per the vendor.
Doodle
Best for: Groups trying to agree a time for anything from a meeting to a project kick-off; the vendor's pitch is speed and simplicity.
Nylas
Best for: Developers who'd rather plug into an API than build calendar connections themselves; the vendor says it links many email, calendar and meeting providers.
SavvyCal
Best for: Teams that want control over buffers, daily limits and preferred times on shared links, so calendars don't fill up wall to wall.
Setmore
Best for: Front desks that want bookings coming in day and night with reminders sent automatically, which the vendor says ends the back-and-forth.
SimplyBook.me
Best for: Service businesses in many industries that want clients to book and pay online, as the vendor describes it.
TidyCal
Best for: Freelancers selling sessions in packages, with payments and calendar sync built into a single booking page, as the vendor puts it.
TimeTap
Best for: Organisations that want booking admin automated across many departments, using what the vendor calls a feature-rich scheduler.
YouCanBook.me
Best for: Businesses that care how the booking step looks to customers and want room to customise it, per the vendor.
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Nine scheduling options side by side
| Tool | Type | Good for |
|---|---|---|
| Acuity Scheduling | Appointment booking | Client-facing businesses customising their booking experience |
| Doodle | Group scheduling | Agreeing a time across a group of people |
| Nylas | Calendar and email API | Developers adding calendar and email connections to a product |
| SavvyCal | Booking links | Protecting your calendar with buffers and limits |
| Setmore | Appointment scheduling | Front desks taking bookings day and night |
| SimplyBook.me | Booking system | Service businesses in many industries taking online bookings |
| TidyCal | Booking page | Freelancers selling sessions in packages |
| TimeTap | Enterprise scheduling | Organisations automating booking admin across departments |
| YouCanBook.me | Customisable scheduling | Booking steps that match your brand |
Where each one fits
For developers
Nylas is the closest match for software teams: an API for calendar, email and meeting connections you build on top of.
For client bookings
Acuity Scheduling, Setmore, SimplyBook.me and YouCanBook.me suit businesses where clients book appointments or services, with reminders and a branded page.
For freelancers and small teams
SavvyCal and TidyCal keep things light for people sharing a link for calls and sessions.
For groups and larger organisations
Doodle helps a group agree a time, while TimeTap aims at organisations with several departments taking appointments.
My advice if you're replacing a calendar API
If you're a software team, don't switch providers in one go. Run the new API alongside the old one for a small group of users and compare what happens when a meeting is moved or deleted in someone's own calendar. Those edge cases are where calendar integrations break, and your support inbox will tell you about it.
If you're a business that just needs bookings, skip the API altogether and choose from the booking tools. My guide on choosing a scheduling tool for client bookings walks through the decision, and my roundup of trustworthy scheduling tool reviews helps you sort useful reviews from noise.
Questions to ask your developers first
- Which calendar providers do our users connect today, and does the new option support all of them?
- What happens in our app when someone moves a meeting directly in their own calendar?
- How much of the scheduling interface would we build ourselves, and how long would that take?
- Where is calendar data stored, and does that meet the privacy rules where our users live?
- Could a ready-made booking tool do the job instead of building it ourselves?
Do you make scheduling software or a calendar API? Tool makers can ask to be considered for a featured place on this list.
Want your tool on this list? Featured spots and reviews here are paid partnerships. Here's how to partner with me.
Frequently asked questions
What's a calendar API?
It's a service that lets your software read and write events in people's calendars, such as Google or Outlook, without building each connection yourself.
Do I need a calendar API or a booking tool?
If you're adding scheduling to software you sell, you need an API. If you just want people to book time with you or your team, a booking tool is quicker and simpler.
What happens when someone moves a meeting in their own calendar?
A good integration notices the change and updates the booking. Test this with every calendar your users rely on, because it's where problems usually appear.
Can booking tools handle several team members?
Many can, with shared pages, round-robin assignment or a choice of staff member. Check how each tool handles availability across the team.
Is calendar data covered by privacy rules?
Yes, calendar entries often hold personal data. Rules vary by country, so check your regulator's guidance and each vendor's data handling terms.
