Integrations

booknslot talks to three external systems. All are optional depending on your setup.

Resend (email)

booknslot sends OTP verification codes and booking confirmations. Resend is the recommended transactional email provider — the plugin ships with a direct HTTP integration (no Composer SDK).

Setup

1. Create a Resend account at resend.com.
2. Verify a sending domain — unverified Resend accounts can only deliver email to the account owner’s inbox. Without verification, your bookers won’t receive OTPs.
3. Create an API key: Resend dashboard → API Keys → Create.
4. In WordPress: Booking Manager → Settings → Email, paste the key into Resend API key. Set Sender email to an address on your verified domain (e.g. no-reply@yourschool.edu).
5. Save.

Fallback

If no Resend key is set, booknslot falls back to WordPress’s wp_mail(). This works but often hits spam filters on shared hosts — Resend (or any transactional provider) is strongly recommended for production.

LemonSqueezy (licensing + distribution)

LemonSqueezy handles every step of the purchase and licensing flow:

1. Customer buys on booknslot.com → LemonSqueezy charges the card.
2. LemonSqueezy emails the customer a unique license key + a download link for the .zip.
3. The customer installs the .zip and pastes the license key into Booking Manager → License.
4. The plugin validates the key against LemonSqueezy’s API (/licenses/activate).
5. A daily WordPress cron revalidates the key. A 7-day grace period covers transient LS API outages.

Refunds, upgrades, and license transfers all happen inside the LemonSqueezy customer portal.

WordPress (shortcode embed)

[booking_manager slug="your-page-slug"]

The shortcode registers on plugin activation. It works in:

• Block editor (Shortcode block or Paragraph block that contains just the shortcode)
• Classic editor
• do_shortcode() calls in theme templates
• Page builders that support shortcode blocks (Elementor, Divi, Bricks)

The React widget is lazy-loaded — it only downloads on pages where the shortcode is actually present.

iCal (.ics calendar attachments)

When a booking is approved (auto or maintainer-confirmed), the confirmation email includes a standards-compliant .ics file. Apple Calendar, Outlook, Google Calendar, and every other major calendar client parse it and let the booker add the event with one click.

No separate setup — this works out of the box. The .ics generator is hand-written per RFC 5545 inside the plugin (no external library).

What is not an integration in v1.0.0

• WooCommerce — deposits via WC are on the roadmap but not shipped. Bookings today do not charge the booker.
• Google Calendar sync (bidirectional) — the .ics attachment is a one-way push. Full two-way sync is on the roadmap.
• Zapier / webhooks — not available yet. If you need an automation trigger, the REST API under booknslot/v1/ is polled-readable from the site owner’s end.