> ## Documentation Index > Fetch the complete documentation index at: https://partners.usecharlie.ai/llms.txt > Use this file to discover all available pages before exploring further. # Product overview. > A technical digest of Charlie's capabilities — everything you need before a client conversation. This page gives you a structured overview of what Charlie does and how it works, drawn from the product documentation. It's not a user manual — it's the context you need to hold a credible technical conversation with a client. For the full documentation, visit [docs.usecharlie.ai](https://docs.usecharlie.ai). *** ## How Charlie fits into Shopify. Charlie runs as **Shopify Functions** — meaning all routing logic executes natively inside Shopify's infrastructure at checkout. No external API calls, no latency added, no middleware to maintain. Charlie augments Shopify, it doesn't replace it: | Shopify native | Charlie adds | | ------------------- | ---------------------------------------- | | Available inventory | Sellable inventory with safety stock | | Basic order routing | 6 types of advanced routing rules | | Location management | Daily capacity limits + performance data | | Checkout process | Fulfillment constraints | Zero IT burden. No ERP integration needed. Clean uninstall — all data stored in Shopify metafields. *** ## Order routing. Charlie offers 2 complementary layers of routing control. ### Fulfillment constraints - hard rules. Constraints **block** specific locations from fulfilling specific orders. If no eligible location remains, checkout is blocked. Use for absolute business requirements. Examples: fragile items can never ship from a small store, a specific brand must only ship from a dedicated location. **Constraint types:** product rules, customer rules, cart rules, shipment limits. ### Routing rules - soft rules. Routing rules **rank** locations by preference without blocking any. If the top-ranked location is out of stock, Charlie falls back to the next. Use for optimization. **6 available rule types:** | Rule | Logic | | -------------------------- | ---------------------------------------------------------------------- | | **Ranked location groups** | Create priority tiers — warehouse first, then stores, etc. | | **Product rules** | Route based on what's in the cart (collection, brand, product tag) | | **Customer rules** | Route based on who's ordering (B2B, VIP, customer tag) | | **Cart rules** | Route based on cart properties (quantity, value, line item attributes) | | **Inventory rules** | Prefer locations with more available stock — reduces split shipments | | **Capacity rules** | Prefer locations with more available capacity — avoids overload | Rules can be combined and ordered. Charlie evaluates them sequentially — earlier rules have higher priority. Rules can be enabled/disabled independently, which is useful for peak season pre-configuration. *** ## Safety stock. Safety stock reserves a portion of inventory so it never reaches the sales channels. Sellable inventory = available inventory - safety stock. **2 configuration modes:** * **Prefer other locations** — soft approach, overflows when no alternative exists * **Block orders** — hard block, location excluded when threshold is reached **2 configuration methods:** * **Rules-based** (recommended) — apply in bulk across products, collections, and location types. Fixed quantity or percentage. * **Variant-level** — set per product variant for granular exceptions **Channel enforcement:** * Online store cart block — prevents checkout when cart exceeds sellable stock * Theme integration — displays accurate sellable stock on storefront (requires front-end dev — see [Custom development](/technical/custom-development)) * Shopify POS — shows sellable stock to store staff, preventing sells through reserves *** ## Analytics. Charlie's analytics dashboard tracks fulfillment network performance across all locations. **Overview metrics:** revenue, average fulfillment time, on-time rate. **Fulfillment flow:** routed > on hold > rerouted > fulfilled. Breaks down where bottlenecks occur. **Per-location table:** revenue, orders fulfilled, average time, on-time rate — comparable across all locations. **Reroute analysis:** which locations orders are being moved between, and at what frequency. Frequent reroutes from the same location signal capacity or stock issues. **Export:** CSV export per filter (location performance + reroute patterns). PDF available. *** ## Automations. Charlie provides pre-built **Shopify Flow** templates. No third-party tools, no custom code. Current template: schedule location capacity by day of week — set different order limits per day automatically (e.g., 100 orders Mon-Thu, 50 on Saturday, 0 on Sunday). Custom automations can be built from scratch using Charlie's Flow action: **Set location capacity**. *** ## Activity logs. Full audit trail of all configuration changes — who changed what, when, and whether it was a team member or the system. Covers locations, safety stock rules, fulfillment constraints, shipment limits, and app settings. Searchable and filterable by action type, resource type, and date. *** ## Locations. Charlie supports multiple location types (warehouse, store, etc.) with tags for use in routing rules. Each location can have a daily order capacity limit. Capacity feeds directly into routing decisions. Third-party tools and ERP compatibility.