Development of a Booking Platform for Services
Imagine two clients hitting "Book" on the same time slot simultaneously. That race condition is the root cause of double bookings and lost orders. We build booking platforms that eliminate this problem from day one. With over 5 years of experience ranging from solo practitioners to marketplaces with thousands of providers, we know how to schedule, take payments, and sync calendars reliably.
The Problem: Double Booking and Lost Orders
A typical scenario: a beauty salon uses Excel to manage appointments. Clients call, double bookings happen, and orders get lost. We build automated systems that handle scheduling, online payments, and calendar sync. The most common technical challenge is the race condition: when two clients try to book the same slot at the same time. Without proper locking, both succeed, leading to conflict.
How Our Schedule Model Prevents Conflicts
The provider's schedule defines available booking slots. The foundation is two tables: schedules for regular hours and schedule_exceptions for exceptions (vacations, urgent matters). The free slot generation algorithm: take working hours from schedules → subtract already booked slots from bookings → subtract buffer time between appointments → return free intervals.
-- Regular working schedule CREATE TABLE schedules ( provider_id, day_of_week INT (0-6), start_time TIME, end_time TIME ); -- Exceptions (weekends, vacation) CREATE TABLE schedule_exceptions ( provider_id, exception_date DATE, is_available BOOLEAN, -- false = unavailable custom_start TIME, custom_end TIME -- alternative schedule for that day ); -- Booked slots CREATE TABLE bookings ( id, provider_id, client_id, service_id, start_at TIMESTAMPTZ, end_at TIMESTAMPTZ, status ENUM('pending', 'confirmed', 'cancelled', 'completed') ); Eliminating Double Booking with PostgreSQL Advisory Locks
Double booking is the classic problem in booking systems. Our approach uses PostgreSQL advisory locks (see PostgreSQL documentation) to serialize concurrent bookings for the same slot.
SELECT pg_advisory_xact_lock(provider_id, unix_timestamp_of_slot); -- check availability -- create booking -- lock is released automatically at transaction end An alternative is a unique index on (provider_id, start_at) with INSERT ON CONFLICT DO NOTHING. However, we prefer advisory locks because they don't require uniqueness for all booking states (e.g., cancelled bookings should not block slots). Advisory locks are also faster under high load (over 100 bookings per second).
Managing Provider Services and Buffers
Each provider configures their services: name, description, duration, price, buffer time after session, and client requirements. Buffer time is critical: if a session lasts one hour, a 15-minute buffer means the next slot starts only after 1:15. This prevents lateness and gives time for preparation.
Cancellation Policies
Standard cancellation policies are compared below:
| Policy | Full refund cancellation period | Partial refund cancellation period | Late/no-show refund |
|---|---|---|---|
| Flexible | 24 hours before | – | 100% |
| Moderate | 5 days before | 24 hours before (50%) | 50% |
| Strict | 14 days before (50%) | Later – 0% | 0% |
The provider chooses one policy. On client-initiated cancellation, the refund is calculated automatically via Stripe Refund. On provider-initiated cancellation, the client gets a full refund.
Google Calendar Integration Step by Step
- OAuth2 Authorization: The provider authorizes access to their calendar via standard OAuth2 flow.
- Event Synchronization: New bookings automatically create events in Google Calendar via Google Calendar API. Events block slots on the platform.
- Backward Sync: Blocking events from the provider's calendar (e.g., personal meetings) mark them as unavailable.
- Change Handling: On cancellation, the corresponding event is deleted or marked as confirmed.
Automated Reminders and Notifications
Automated reminders reduce no-shows. We set up:
- Booking confirmation (immediate)
- Reminder 24 hours before (email + SMS via Twilio)
- Reminder 1 hour before (push notification in mobile app)
- Feedback request 2 hours after visit
Comparison of Double Booking Prevention Methods
| Method | Performance | Reliability | Complexity |
|---|---|---|---|
| Advisory Lock | High (2x faster) | 100% guarantee | Medium |
| Unique Index | Medium | 99.9% (possible collisions) | Low |
The choice depends on load. For high-traffic platforms (100+ requests/s), we recommend advisory locks.
What's Included in Our Work
When you order a booking platform development, we provide:
- Architectural diagram and API documentation
- Source code in a Git repository
- Database migrations for all environments
- Payment gateway integration (Stripe, YooKassa)
- Google Calendar / Outlook integration
- Notification setup (email, SMS, push)
- Deployment and operations guide
- Administrator and provider training
- 3-month warranty support after launch
Why Choose Us
We have developed over 30 booking systems for various industries—from beauty salons to venue rentals. Our experience guarantees no double booking, reliable payment processing, and scalability to thousands of concurrent requests. Certified PostgreSQL and React engineers. The average reduction in admin time after implementation is 40%, saving up to 150,000 rubles per year. Platform commission is 15%.
Timelines
MVP (provider profile, schedule, booking, payment, notifications): 2 to 3 months. Full-featured marketplace with analytics, mobile app, and multiple providers: 4 to 6 months. Contact us for a project assessment—we'll find the optimal solution and timeline. Order a consultation to discuss details.