CalendarPipe

What it is

CalendarPipe is a calendar sync tool you actually control. You connect your calendars (Google, Microsoft, Apple), set up a rule, and write a tiny JavaScript "gate function" that decides what gets copied across, how it appears, and what stays private.

Think if-this-then-that, but for calendars, and with real code instead of a settings page that can't quite express what you want.

The problem

Every calendar sync tool I tried did one of three things wrong:

1. Synced everything, including the dentist appointment you didn't want your coworkers to see.

2. Required OAuth on both sides, which doesn't work if the target calendar is your work account locked down by IT.

3. Gave you a settings page with five toggles when you needed twenty.

CalendarPipe fixes all three.

How it works

1. Connect your calendars. Google, Microsoft 365, Outlook, iCloud/Apple. Direct OAuth, or — and this is the differentiator — invitation-based delivery, where events arrive at the target as standard iMIP email invitations. No OAuth needed on the receiving side. Works with any calendar that reads email invites, which is all of them.

2. Write a gate function. A small pure JavaScript function that takes an event and returns either null (skip it) or a new shape for how it should appear on the other side.

function gate(event: GateEvent): GateResult {
if (
(event.title.toLowerCase().includes("j:"))
&& (event.isWeekday === true)
&& (event.isAllDay === false)) {
return {
pass: true,
transform: {
title: "Personal Commitment",
visibility: "public",
showAs: "busy",
location: '',
preBufferMinutes: !!event.location ? 30 : 0,
postBufferMinutes: !!event.location ? 30 : 0
}
};
}
return { pass: false };
}

Time, duration, and all-day status always come from the origin — gate functions control what syncs, never when. That invariant keeps things predictable.

3. Events flow. Edit a meeting in your source calendar, the change propagates within minutes. Cancel it, the synced copy disappears.

Who it's for

• People with multiple calendars — family + work, two jobs, founder juggling personal and company calendars.

• Couples and families who want their schedules visible to each other without exposing every detail.

• Consultants and contractors managing client calendars they don't own.

• AI agents — there's a full REST API and Skill layer so agents can spin up and manage their own hosted calendars. Useful if you're building scheduling automation.

What makes it different

• Invitation-based delivery. The only sync tool I know of that works without needing OAuth on the target calendar. This is the one that unlocks corporate calendars and any setup where you don't fully control both sides.

• Code, not toggles. The gate function gives you everything: regex, time math, attendee filters, custom titles per event type. Monaco editor in the browser with full type hints.

• Hosted Calendars for agents. REST API + Skill so AI agents can manage calendars natively.

• Privacy-first. Hide titles, descriptions, locations — whatever you want — on the synced side, while keeping originals untouched.

Tech & trust

Built on Next.js 15, Supabase, Stripe, and Resend. Gate functions run in a QuickJS-WASM sandbox (50ms timeout, 4MB memory cap, fresh runtime per execution — no network, no filesystem, no state leaks). Sync window is 21 days with full resync triggered before coverage drops below 7 days, so recurring events don't fall off the edge.

Pricing

• Free — 2 connections, 1 rule, 15-minute sync interval.

• Pro — $4/month or $40/year. More connections, more rules, faster sync, full API access.