Hollow Reserve is an experience commerce app for appointment-led Shopify merchants. We process booking, client ledger, journey, staff, and connector data so merchants can run storefront booking, intake, client history, and follow-up workflows.

Arcanum Hollow Labs acts as a service provider to the merchant. The merchant remains responsible for their storefront, customer relationships, and compliance with applicable privacy laws — including notices for booking, SMS, and marketing where required.

Shop identity: shop domain, timezone, subscription plan tier, and Reserve shop profile settings (widget configuration, notification preferences, and embed signing material).

Authorization: encrypted Shopify offline access tokens and session metadata required to call the Shopify Admin API on the merchant's behalf.

Client ledger (customer PII): email, first and last name, phone, Shopify customer id when linked, tags, notes, lifetime value, and related client records.

Booking and journey data: appointments, experience instances, waitlist entries, memberships or packages, credits, communications, reviews, and journey event payloads (which may include intake answers the customer or merchant submits).

Staff data: staff member name and email; Google Calendar OAuth refresh tokens when a staff calendar connection is enabled.

Connector credentials: encrypted Resend API keys, Slack webhook URLs, Twilio credentials, and Klaviyo private API keys the merchant saves in Settings.

Billing: Shopify app subscription status via Shopify Billing API (no separate payment card storage in Hollow Reserve).

We use the data above solely to provide Hollow Reserve functionality: storefront booking, client ledger and journey management, staff calendars, merchant-configured email/SMS/Slack alerts, optional Klaviyo journey events, and app billing.

We do not use merchant or customer data for advertising, resale, or unrelated analytics.

We process the data needed to operate booking, client history, and merchant-configured notifications. Merchants control which connectors and notification channels are enabled.

Merchants can disable features or uninstall the app to stop processing. Customers should contact the merchant for storefront privacy requests; merchants may also contact us for deletion assistance as described below.

Merchants install Hollow Reserve under the Shopify Partner Program terms and this data processing description.

We tell merchants what we process through this page, in-app Settings and documentation, and Shopify App Store listing materials.

Use of Hollow Reserve is limited to the experience commerce purposes described here.

Hollow Reserve does not replace the merchant's obligation to provide privacy notices or obtain consent. Booking widgets and messaging run under the merchant's brand and configuration.

Merchants are responsible for ensuring transactional SMS, marketing messages, and intake collection comply with applicable law and Shopify customer privacy settings in their region.

We do not sell, rent, or trade merchant or customer personal data. We do not share data with third parties except subprocessors listed below, solely to operate the service.

Reserve applies merchant-defined booking, cancellation, waitlist, and notification rules. These are merchant operations workflows for appointments and client journeys, not decisions with legal or similarly significant effects on consumers beyond the merchant's own policies.

Hollow Reserve does not make credit, employment, housing, or comparable eligibility decisions about customers.

Shop credentials, client ledger records, appointments, journeys, and connector secrets are retained while the app is installed and needed to operate the merchant's booking business.

When Shopify sends a customers/redact webhook with a customer email, we delete matching ClientLedger records for that shop. Shop redaction and uninstall remove Reserve datasets associated with the store, subject to short operational backup cycles.

customers/data_request webhooks are acknowledged; merchants may contact us for export assistance. Merchants remain the primary contact for their customers' privacy requests.

Data in transit is protected with TLS (HTTPS) between Shopify, our application, and integrated services such as Slack, Twilio, and Google.

Sensitive values at rest (Shopify access tokens, connector secrets, and calendar OAuth tokens) are encrypted using application-level encryption before storage in our database.

Access to production systems is limited to authorized Arcanum Hollow Labs personnel with a business need.

Shopify — commerce platform, webhooks, Admin API, metaobjects where used, and app billing.

Hosting and database providers — application hosting and PostgreSQL storage for shop configuration, bookings, and client ledger data.

Resend (optional) — merchant-configured email alerts and transactional messages via the merchant's Resend account.

Slack (optional) — merchant-configured booking or ops alerts to the merchant's Slack workspace.

Twilio (optional) — merchant-configured SMS when SMS credentials are connected.

Klaviyo (optional) — when connected, journey-related track events may include customer email and booking properties defined by Reserve.

Google (optional) — Google Calendar API when staff calendar connections are enabled.

When a merchant uninstalls Hollow Reserve, we receive Shopify's app/uninstalled webhook and remove shop credentials, connectors, appointments, journeys, client ledgers, staff calendar connections, and related Reserve data associated with that store.

Residual backups may persist for a limited period for disaster recovery, after which they are purged according to our retention practices.

Arcanum Hollow Labs

Privacy and data requests: privacy@arcanumhollow.com

For merchant support related to Hollow Reserve, use the contact options on arcanumhollow.com or your Arcanum engagement lead.