---
title: "Conflict detection — Appointments for Laravel | Roundly"
description: "Block double-bookings per call or globally, inspect the clashing appointments, and check availability with Appointments::isAvailable()."
url: https://roundly-consulting.com/open-source/docs/appointments-for-laravel/conflict-detection
language: en
---

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[Appointments for Laravel](https://roundly-consulting.com/open-source/docs/appointments-for-laravel.md)

# Conflict detection

Turn on double-booking protection for one call with preventConflicts(). When a participant already has an overlapping booking, SchedulingConflictException is thrown before anything is written, and it carries the conflicting appointments:

```php
use RoundlyConsulting\Appointments\Exceptions\SchedulingConflictException;
use RoundlyConsulting\Appointments\Facades\Appointments;

try {
    Appointments::schedule('Follow-up')
        ->startingAt('2026-07-01 09:30')
        ->lasting(60)
        ->withParticipant($doctor)
        ->preventConflicts()
        ->create();
} catch (SchedulingConflictException $e) {
    $e->conflicts;      // Collection<int, Appointment> — the bookings this slot overlaps
    $e->getMessage();   // The requested time conflicts with 1 existing appointment(s).
}
```

Or guard every create, reschedule and participant add in the app:

```php
// config/appointments.php — guard every create, reschedule and participant add
'prevent_conflicts' => true,
```

## What counts as a conflict

- An existing appointment conflicts when it starts before the new end and ends after the new start. Touching ranges — one ends exactly when the next begins — don’t conflict.
- An existing appointment without an ends\_at is treated as open-ended.
- Cancelled and declined appointments are ignored; pending, confirmed, completed and no-show ones count.
- On create, every participant passed to the builder or DTO is checked. On reschedule, the appointment’s current participants are checked and the appointment never clashes with itself. On participants()->add(), the added model is checked against the appointment’s window.
- The per-call flag only switches the guard on — with prevent\_conflicts set to true, every create, reschedule and participant add is guarded.
- In a recurring series every occurrence is checked, and one conflict rolls back the whole series.

## Safe under concurrency

The check holds when two requests book the same person at once. It runs in the transaction that writes, after locking each participant’s row — and, for a reschedule or an added participant, the appointment’s row — so two simultaneous bookings of one person can’t both pass it. Locks are always taken in the same order, so bookings that share participants don’t deadlock. SQLite has no row locks; it serializes writers instead.

## Checking availability

Ask the facade directly — for example to grey out busy slots before someone picks one. Both methods read only and apply the same rules. $start and $end may be Carbon instances in any timezone; they are compared as the instants they are:

```php
use RoundlyConsulting\Appointments\Facades\Appointments;

Appointments::isAvailable($doctor, $start, $end);                       // bool
Appointments::conflicts($doctor, $start, $end);                         // Collection<int, Appointment>
Appointments::conflicts($doctor, $start, $end, ignore: $appointment);   // leave one booking out
```

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