Appointments, without the friction

Time, handled beautifully.

Blackthorn gives independent professionals a refined, private booking experience — with precise availability, cool-out time, client limits, live slot control and calendar-ready email confirmations.

See the booking experience →Download Blackthorn

Self-hostedApple Calendar-readyLight & dark themesEmbeddable widget

Live appointment availabilityClient-facing booking

Built around real working patterns

Your calendar should work around you.

Blackthorn goes beyond open/closed hours. It gives the provider control over the rhythm of a working day, while keeping booking simple for clients.

Availability with breathing room

Set weekly opening hours, date-specific exceptions, session duration and dedicated cool-out time between appointments.

Flexible scheduling

Smart client limits

Define how close together a client may book and how many upcoming appointments they may hold at once.

Per-client safeguards

Calendar-ready email

Booking messages can include standard calendar event files, making appointments easy to add to Apple Calendar and other compatible calendars.

.ics invitations

Capacity when you need it

Run one-to-one sessions or allow multiple students to join the same service and start time, up to a shared capacity.

1–1000 places

Your brand, not a template

Choose a title, upload your own icon and switch between five visual styles, each with a matching day and Night Shift palette.

Custom appearance

Embed live availability

Use the compact website widget to let visitors choose a service, date and available time before completing their booking in Blackthorn.

Same-origin iframe

A polished client experience

Comfortable in daylight. Calm after dark.

The booking interface stays clear, focused and highly legible in either mode, with availability and booking rules communicated without clutter.

Blackthorn booking interface in light mode — **Day mode**Bright, restrained, professional

Blackthorn booking interface in dark mode — **Night Shift**Low-glare, warm, focused

Precise control, quietly implemented

Make rules once. Let Blackthorn enforce them.

Availability is checked again at confirmation time, helping prevent stale pages or simultaneous requests from creating conflicts.

↳

Booking window

Choose how soon and how far ahead appointments can be booked.

↳

Date overrides

Close a particular date or replace your usual hours without changing the weekly schedule.

↳

Cross-service conflict checks

Overlaps account for both appointment duration and the cool-out period around each booking.

↳

Admin workspace

Manage appointments, services, availability, appearance, team permissions and email diagnostics from one place.

Email + calendar

Bookings arrive ready for the calendar.

Client confirmations and administrator notifications are queued with the appointment. Calendar event attachments use the standard .ics format for easy import into Apple Calendar and compatible apps.

✓Appointment confirmed
Client confirmation queued

↗Calendar event
blackthorn-appointment.ics

✦Admin alert
New booking notification

Apple Calendar · Default Calendar · Teams settings

Private by design

Your booking data stays on your installation.

Blackthorn is a PHP application backed by SQLite. It can keep its database, settings and mail queue in a private directory outside the public website root, without requiring a separate MySQL account.

PPHP 8.2+
Simple hosting requirements

SSQLite
Transactional local database

↻Mail queue
Retries and delivery diagnostics

Straightforward deployment

A focused app, without a sprawling stack.

Upload Blackthorn to a PHP website directory, complete the secure first-run setup, configure your sender address and scheduled mail worker, then tailor services and availability from the admin panel.

Minimum requirements: PHP 8.2 and SQLite.

Download Blackthorn

ZIP archive · 2.0 MB. Extract the archive and read START-HERE.txt for setup instructions.

PHP8.2 or newerSQLitePDO extensionHTTPSRequired in productionmbstringPHP extensionGDFor custom icon uploadsNo build stepNo Node or Composer required

Blackthorn

Booking software with boundaries built in.

Give clients a simple path to an appointment while keeping control of the time before it, the time after it, and everything in between.

Download Blackthorn Browse features