Your stack is already supported — even the weird parts
Every business runs on a different mix of tools. Callender doesn't ask you to migrate; it comes to where your data lives.
Mainstream sources, out of the box
Calendars, email, messaging, spreadsheets and common booking and CRM systems connect in minutes with guided setup.
One-sentence custom connectors
"Connect our clinic management system's appointment API." That's the whole spec. Callender builds, tests and maintains the connector for you.
Any open, lawful source
If a system exposes a legitimate interface — REST, database, file export, webhook — it can feed your calendar. Compliance checks are part of onboarding, not an afterthought.
Two-way, not read-only
Callender doesn't just read. Confirmed bookings, reschedules and cancellations flow back to the source system, so both sides stay in step.
What 'one sentence' actually looks like
Custom integrations used to mean a quote, a project plan and six weeks. Here is the whole lifecycle on Callender:
You describe the connection in plain language — the system, what should sync, and in which direction.
Callender inspects the interface, confirms it's open and lawful to use, and proposes a field mapping for your approval.
The connector goes live and is monitored continuously. If the upstream API changes, it heals or alerts — you don't babysit it.
Frequently asked questions
What counts as an 'open, lawful' data source?
Any system you have legitimate access rights to, via a documented or otherwise permitted interface. We verify authorisation during setup and never scrape sources you aren't entitled to.
Do I really not need a developer?
For the vast majority of connections, no. You describe what you need in one sentence; we handle discovery, mapping, testing and maintenance.
How fresh is the synced data?
Connectors sync continuously — changes propagate in seconds where the source supports it, and on a tight schedule where it doesn't.