Rain POS API
Rain (Rain Retail Software) is a cloud point-of-sale, ecommerce, and inventory platform built for specialty retailers like craft, music, bike, quilt, jewelry, and outdoor shops. Rain has no public developer API, so the sales, inventory, customer, and class data that runs the store stays trapped in the portal. An unofficial API lets you programmatically pull products, inventory levels, orders, customers, and loyalty activity—and push updates like inventory adjustments, customer records, and class registrations back into Rain.
What is Rain POS?
Rain (Rain Retail Software) is a cloud point-of-sale and inventory management platform built specifically for specialty independent retailers—craft and fabric stores, boutiques, music shops, bike shops, jewelry stores, dive and ski shops, and other outdoor retailers. Rain unifies the brick-and-mortar register with an integrated ecommerce storefront so inventory, customers, and sales stay in sync across both channels.
Core product areas include:
- Retail Point of Sale (register, barcode scanning, payment processing)
- Integrated Ecommerce (online storefront with real-time inventory sync)
- Inventory Management (reordering, receiving, brick-and-mortar/online sync)
- Retail Marketing (automated email and text marketing, review management)
- Customer Management and Loyalty tracking
- Class signups with online registration and text reminders
Common data entities:
- Products, Variants, Categories, Built-in Catalog Items
- Inventory Levels, Stock Adjustments, Receiving, Reorder Points
- Orders, Transactions, Online and In-Store Sales
- Customers, Loyalty Activity, Top Customers
- Classes, Registrations, Reminders
- Marketing Campaigns, Email/Text Sends, Reviews
The Rain POS Integration Challenge
Specialty retailers run their entire store on Rain, but the data that drives that store is locked behind the web portal with no public developer API to reach it:
- No public API: Rain markets to retailers, not developers—there is no published developer API or self-serve API keys, so the only documented way in is the web portal
- Portal-gated data: Sales, inventory, customer, and class data lives behind authenticated screens designed for store staff, not machine-to-machine access
- Limited prebuilt connectors: Integrations are restricted to a fixed list (Shopify, QuickBooks Online, Clientbook, Notions Marketing)—anything outside that set has no path
- Two-channel reconciliation: Inventory and orders span the in-store register and the integrated ecommerce site, so a generic ecommerce scraper misses the brick-and-mortar half of the store
- Manual export ceiling: Reporting and inventory data come out as portal screens or CSV exports, which break automation and lag real-time stock levels
- Session-based authentication: Access depends on logged-in browser sessions rather than tokens, complicating any headless or scheduled automation
How Supergood Creates Rain POS APIs
Supergood reverse-engineers the authenticated Rain portal flows that store owners use every day and exposes them as a clean, resilient REST API—so your products, inventory, orders, customers, and class data become programmatically accessible without waiting on a vendor API that does not exist.
- Handles Rain username/password login and session continuity securely
- Maintains live sessions with automated refresh and change detection
- Reconciles in-store and ecommerce inventory so one product object reflects both channels
- Normalizes products, orders, customers, and loyalty records into consistent JSON you integrate once
Use Rain POS with AI agents: Rain POS MCP Server →
Getting Started
- Schedule Integration Assessment
Book a 30-minute session to confirm your Rain modules, channels, and authentication model.
- Supergood Generates and Validates Your API
We deliver a production-ready Rain adapter tailored to your store configuration and catalog.
- Deploy with Monitoring
Go live with continuous monitoring and automatic adaptation as Rain evolves.
API Endpoints
Authentication
/authenticateAuthenticate to a Rain store account with username/password and obtain a managed session for downstream calls.
Catalog
/productsList products and variants with filters for category, status, price, and channel availability across in-store and online.
Inventory
/inventoryRetrieve real-time stock levels, reorder points, and receiving status reconciled across the register and ecommerce store.
Inventory
/adjust_inventoryPost a stock adjustment, receiving, or transfer against a product or variant in Rain.
Orders
/ordersPull in-store and online orders and transactions with filters for date range, channel, customer, and status.
Customers
/customersList customers with loyalty activity, contact details, and top-customer flags for marketing and CRM sync.
Use Cases
Sync inventory across register and online store
- Pull real-time stock levels for every product and variant out of Rain - Reconcile brick-and-mortar and ecommerce quantities into one source of truth - Push adjustments, receiving, and reorder points back without manual portal entry
Centralize sales and order reporting
- Stream in-store and online orders into a warehouse or BI tool - Match transactions across channels for unified daily and monthly reporting - Surface top-selling products and inventory turnover automatically
Keep customer and loyalty data in sync
- Pull customer records, loyalty activity, and top-customer flags from Rain - Push the unified profile into your CRM, email, and SMS marketing tools - Trigger campaigns off purchase history and loyalty milestones
Automate class registrations and reminders
- Sync class schedules and online registrations out of Rain - Route signups and capacity changes to scheduling and notification systems - Trigger text and email reminders without staff intervention
Technical Specifications
Authentication
Rain username/password handled in a managed, encrypted session
Connectivity
Authenticated portal flows reverse-engineered into a REST API surface
Response format
Normalized JSON across products, inventory, orders, customers, and classes
Rate limits
Adaptive throttling tuned to your store to avoid Rain-side limits
Session management
Automatic session refresh, re-login handling, and credential rotation
Data freshness
Near real-time reads for inventory and orders with optional scheduled batch syncs
Security
Encrypted credential vault, scoped access, SOC 2-aligned controls, and audit logging
Webhooks
Event-style callbacks for new orders, inventory changes, and class registrations
Latency
Sub-second reads on cached catalog and inventory; multi-second writes for adjustments and registrations
Throughput
Horizontally scaled workers sized to single- and multi-store catalog volume
Reliability
Retry, backoff, and idempotency keys for inventory adjustments and order writes
Adaptation
Continuous monitoring of Rain portal changes and automatic adapter updates
Frequently asked questions
No. Rain markets to specialty retailers rather than developers and does not publish a self-serve developer API or API keys. Supergood works against the same authenticated portal flows your staff use to expose a clean REST API for your store's data.
Yes. Rain unifies the brick-and-mortar register with an integrated ecommerce storefront, and Supergood reconciles inventory and orders across both channels so each product, stock level, and order reflects the full picture.
Both. Beyond reads, you can post inventory adjustments and receiving, update customer records, and manage class registrations through the same normalized API surface.
Rain ships a fixed set of prebuilt connectors—Shopify, QuickBooks Online, Clientbook, and Notions Marketing. Anything outside that list has no path. Supergood gives you a general-purpose API so you can connect Rain to any system you choose.
Supergood continuously monitors the Rain portal for changes and automatically updates the adapter, so your integration keeps working without you tracking vendor UI updates.