Bookslot and Calendly solve the same problem from opposite directions: one is source-available software you can own outright for $39, the other is a subscription at $10/user/mo run entirely on someone else's servers.
Head to head
| Bookslot | Calendly | |
|---|---|---|
| Price | $39 once | $10/user/month, forever |
| Cost after 3 years | $39 | $360 |
| Your own domain | Yes | Their domain (branding is a paid add-on) |
| Data ownership | SQLite file on your server | Their cloud |
| Buffers, min notice, date limits | Yes | Yes |
| Email + ICS invites | Yes (BYO SMTP) | Yes |
| Cancel/reschedule links | Yes | Yes |
| Telemetry / tracking | None | Their ToS |
What Bookslot does well
- Event types — Name, duration, description, color, buffers, minimum notice, max days ahead — each with its own public link.
- Weekly availability editor — Per-day time ranges in your timezone, plus one-off blocked dates and times.
- Timezone-correct slot math — Stored in UTC, computed in your timezone (DST-safe, unit-tested), displayed in the visitor's.
- Double-booking protection — Slot validity re-checked inside a SQLite transaction at booking time.
What Calendly still does better
There's a real reason Calendly costs what it does: a bigger team, broader integrations and dedicated support behind it. If that ecosystem is genuinely what you need, it's worth paying for.
Which one should you pick
If your workflow depends on Calendly's specific integrations or you'd rather not run anything yourself, stay put — that's a legitimate call. If you're comfortable owning the tool and want to stop paying $10/user/mo for a job your own hardware can do, Bookslot pays for itself and then some: pays for itself in under 4 months vs Calendly — then your booking link is free for life.
Try Bookslot — $39, once
The Calendly you actually own — timezone-correct booking with email + ICS invites.