iCal testing tools
Paste a feed URL or upload an .ics file and inspect events, parse errors, and sync behavior in one workflow.
iCal testing tool
Test your iCal / ICS feeds with iCal Tester Pro
iCal Tester Pro is an online tool that lets you quickly test iCal (ICS) calendar feeds, validate .ics files, and debug sync issues before they hit your users. Paste any iCal URL or upload a file to see exactly which events are exposed, how they're parsed, and whether your feed matches the iCalendar (RFC 5545) standard used by apps like Google Calendar, Apple Calendar, Outlook, Airbnb, and Booking.com.
Built for developers, property managers, and SaaS teams, iCal Tester Pro gives you human-readable event timelines plus low-level validation so you can catch broken dates, time zones, and recurrence rules early. Use it as your main iCal testing tool when building booking engines, PMS/channel managers, scheduling apps, or any integration that depends on reliable ICS feeds.
iCal Tester Pro is an online tool to test iCal/ICS feeds, validate calendar data, and simulate OTA sync, built for developers and property managers.
- No credit card required
- Works with any iCal URL
- Built for Airbnb, Booking.com, VRBO, and PMS teams
Free to start · No credit card · Validate real blocked-night outcomes
Free to start
Import live feeds
Force sync instantly
Compare final availability
Features
iCal testing tools for real calendar sync workflows
Validate feeds, run calendar sync testing, and use a mock iCal server—everything you need to test iCal feeds before production.
ICS validator
Validate .ics files against RFC 5545 patterns and catch malformed dates, time zones, and recurrence rules early.
Calendar sync testing
Simulate OTA and PMS calendar sync for Airbnb, Booking.com, VRBO, and channel-manager integrations.
Mock iCal server
Spin up token-based mock feeds so you can test inbound and outbound sync without wiring a backend.
How it works
A workflow that matches real OTA support and PMS debugging.
Step 1
Import the live feed
Use the same OTA or PMS URL your production workflow already consumes.
Step 2
Force a sync
Check logs, bytes, imported event counts, and current source behavior immediately.
Step 3
Compare the timeline
Validate blocked nights and overlaps instead of stopping at syntax or raw VEVENT text.
Start in minutes
See your first feed in the dashboard in under a minute.
Sign in, add the OTA feed as a subscription, force a sync, and inspect imported events without waiting on partner dashboards.
Why teams switch
Behavior validation beats syntax-only checks.
A feed can be fetchable and structurally valid while still producing the wrong blocked nights, partial imports, or mismatched booking behavior downstream. iCal Tester helps you confirm what actually matters in production.
Inspect real imports
See whether the booking reached the consumer at all.
Validate final availability
Check blocked nights, overlaps, and drift across channels.
Escalate with evidence
Prove whether the issue is upstream, mapping-related, or downstream.
Who this is for
Role-specific outcomes, not generic calendar tooling.
PMS developers
Reduce support tickets by reproducing broken calendar sync behavior before changing production logic.
Channel managers
Prove whether blocked-night drift is coming from the source feed, import layer, or downstream mapping.
Property managers
Catch overbooking risks earlier by checking the final availability behavior across OTA exports.
Support teams
Escalate with evidence instead of screenshots by showing imports, logs, and timeline mismatches.
Comparison
Why syntax-only validation leaves teams guessing.
| Question | Syntax-only validator | iCal Tester |
|---|---|---|
| Can it prove the feed imports into the consumer? | No. It can only inspect the file structure. | Yes. Import the live feed and inspect the result directly. |
| Can it confirm final blocked-night behavior? | No. A valid file can still produce the wrong availability. | Yes. Compare imported events and timeline behavior. |
| Can support teams escalate with evidence? | Usually not beyond syntax output. | Yes. Use logs, imported data, and side-by-side comparisons. |
Guides
One hub plus focused long-tail guides.
Start with the validation hub, then move laterally through focused guides for blocked dates, OTA sync drift, validator checks, and overbooking prevention.
Validation Hub
Ultimate Guide to iCal RFC 5545 Validation for Property Management
Comprehensive hub for OTA and PMS teams: RFC-aware validation workflow, behavior checks, and linked cluster guides for sync troubleshooting.
Getting Started
How to Test iCal / ICS Feeds (Including Airbnb & Booking.com)
Learn how to test iCal and ICS calendar feeds manually, with validator tools, and with iCal Tester Pro for OTA sync simulation and mock server workflows.
Airbnb Guide
Airbnb iCal Not Syncing? How to Debug It
Debug Airbnb iCal sync by importing the live export, forcing a sync, and comparing blocked dates before stale availability causes an overbooking.
Booking.com Guide
How to Test Booking.com Calendar Sync
Test Booking.com calendar sync by importing the live feed, forcing the first sync, and comparing blocked nights across channels before they drift into production.
Validator Guide
RFC 5545 iCal Validator Workflow
Use an RFC 5545 iCal validator workflow that checks fetch, import, and blocked-night behavior instead of stopping at syntax-only linting.
PMS Guide
PMS Integration Best Practices for OTA iCal Sync
Practical patterns for OTA and PMS sync reliability: polling, mapping, observability, and behavior validation.
Prefer a directory view? Go from the hub to all guide pages, then narrow down by OTA workflow or failure pattern.
Open the full directoryFAQ
Questions teams ask before they start testing.
What is iCal Tester Pro?
iCal Tester Pro is an online iCal testing tool that lets you validate and inspect iCal/ICS feeds before using them in your app or booking system. You can paste any iCal URL or upload an .ics file to see all events, check for errors, and confirm that your feed follows the iCalendar (RFC 5545) standard used by popular calendar clients.
How can I test my iCal or ICS feed?
To test your iCal or ICS feed, open iCal Tester Pro, paste your calendar URL or upload your .ics file, and run a validation. The tool parses your feed, lists all events in a readable format, and highlights problems like invalid dates, missing time zones, or malformed recurrence rules so you can fix them before going live.
Who should use iCal Tester Pro?
iCal Tester Pro is built for developers, property managers, and SaaS teams who rely on iCal/ICS feeds for bookings or scheduling. Common use cases include testing Airbnb and Booking.com iCal feeds, validating PMS or channel manager exports, and debugging calendar integrations with Google Calendar, Apple Calendar, or Outlook.
Is iCal Tester Pro different from a simple ICS viewer?
Yes. A simple ICS viewer only shows basic event information, while iCal Tester Pro acts as a full iCal testing tool. It focuses on validating your feed against the iCalendar standard, surfacing parse errors, and helping diagnose sync issues in real-world calendar and booking workflows.
Which calendar apps and platforms are supported?
iCal Tester Pro is designed around the iCalendar (RFC 5545) format used by most major calendar apps and booking platforms. It can help you test feeds intended for Google Calendar, Apple Calendar, Microsoft Outlook, Airbnb, Booking.com, and many property management or channel manager systems that use iCal/ICS links.
What tools can I use to test iCal / ICS feeds?
iCal Tester Pro is the fastest way to test iCal and ICS feeds online: paste a URL, validate the file, and simulate OTA sync behavior. You can also import feeds into Apple Calendar, Google Calendar, or Outlook for manual checks, or use lightweight ICS viewers for a quick peek—but iCal Tester Pro combines validation, mock feeds, and calendar sync testing in one place.
Ready to isolate the problem?
Go from live feed URL to blocked-night proof in one workflow.
Start free, run the first sync immediately, and compare the resulting availability before guests ever see the mistake.