Scheduling we own end to end
We replaced Calendly on our own site with a native booking system: real-time availability, race-proof slot claiming, calendar invites that update themselves, and reschedule/cancel links that just work.
Booking
Visitor picks a slot
live availability
API claims it
validation + rate limiting
Postgres decides
unique index — one winner per slot
Confirmation
Invitee email
calendar invite + manage links
Team email
who, when, what they need
Changes
Reschedule
same event moves — no duplicates
Cancel
idempotent, invite retracted
System map — how the pieces connect
Scheduling tools charge per seat forever, drop a generic embed into your carefully designed site, and own your booking data. For a studio that builds software, that's a strange thing to rent.
The harder problem is correctness: two people picking the same slot at the same moment, calendar invites that duplicate instead of moving when a call is rescheduled, and cancellation links that email scanners click by accident.
We built booking directly into runsynthos.com. Availability is computed, then filtered against confirmed bookings, so a taken slot disappears from the calendar the moment it's claimed.
Double-booking is prevented at the database itself — a unique index arbitrates races, so when two people submit the same slot simultaneously, exactly one wins and the other instantly sees the next options.
Every confirmation email carries reschedule and cancel links backed by unguessable tokens. Rescheduling moves the existing calendar event instead of duplicating it; cancelling retracts it. Mutations are POST-only so link-scanning email security tools can't cancel meetings by prefetching URLs.
People booking a call
- Pick from live availability that already excludes taken slots
- Get a confirmation with a calendar invite attached
- Reschedule or cancel from the email — no account, right up to the call
- Watch their calendar update itself when the time changes
The team
- Get notified on every booking, reschedule, and cancellation
- See the invitee's notes, company, and phone before the call
- Trust the calendar — one slot, one meeting, enforced by the database
Built with
What changed
- Zero per-seat scheduling fees — the system is ours
- Booked slots vanish from availability immediately
- Double-booking is impossible at the database level, not just the UI
- Invitees manage their own booking from the confirmation email
Related service · Workflow & Integration Systems
Need something like this?
Synthos · Custom software & AI automation · Philadelphia