Should you build your own scheduling system?
Calendly seems simple enough to clone. Sometimes it is. Here's when building makes sense.
🎯 Good vibe coding candidate
Basic scheduling is one of the better vibe coding projects. The core logic is straightforward, and open source options like Cal.com mean you don't have to start from scratch.
Two different problems
Scheduling software solves two distinct problems:
1. Meeting scheduling (Calendly model): Someone picks a time from your availability, meeting gets created. This is genuinely simple.
2. Resource booking (Acuity/service business model): Appointments with specific staff, rooms, equipment. Multiple availability sources. This is complex.
Which one you need determines whether building makes sense.
Build / vibe when...
- Simple meeting scheduling only
- Scheduling is core to your product
- You want white-label / embedded
- Single user or simple team
- Cal.com gets you 90% there
Buy when...
- Multi-resource booking (staff + rooms)
- Payment collection required
- Complex routing rules
- CRM/tool integrations matter
- Scheduling isn't your product
The Cal.com factor
Cal.com changed this category. It's open source, self-hostable, and genuinely good. If your needs are "Calendly but self-hosted" or "Calendly but embedded in my product," Cal.com is probably your answer.
You can self-host for free, white-label it, customize it, and own your data. This is the rare case where open source matches the commercial product's quality.
Vibe coding scheduling
A basic scheduling widget is a legitimate vibe coding project:
- Show available time slots from Google Calendar
- Let someone pick a slot
- Create calendar event, send confirmation
Claude can build this in an afternoon. The complexity comes from edge cases: timezone handling, buffer time, recurring availability, multiple calendars, rescheduling...
Recommendation: Start with Cal.com's open source. Customize if needed. Only build from scratch if you have truly unique requirements.
Real cost comparison
For a team of 20 users needing scheduling over 3 years:
| Vibe/Build | Cal.com (Self-host) | Calendly | |
|---|---|---|---|
| Initial cost | $5K – $20K | $2K – $5K | $0 |
| Annual cost | $2K – $8K | $1K – $3K (hosting) | $4K – $10K |
| Time to launch | 1 – 4 weeks | Days | Hours |
| 3-year total | $11K – $44K | $5K – $14K | $12K – $30K |
What people underestimate
Timezones are evil. Your user is in London, books a meeting for "3pm" with someone in Tokyo, and the event should appear correctly in both calendars. Daylight saving transitions make this worse.
Calendar API limits. Google Calendar API has rate limits. At scale, you need to cache availability intelligently.
No-show and rescheduling flows. Reminder emails, rescheduling links, cancellation policies — these add up.
Compare tools
Our take
Cal.com for most. Calendly if you just need it to work. Build only if scheduling IS your product.
Cal.com is the sweet spot: open source quality that matches Calendly, with the ability to self-host and customize. If you're building a product where scheduling is a core feature (like a tutoring marketplace), fork Cal.com or build custom. For everything else, just use Calendly — it's not worth the engineering time.