When you outsource fulfillment to a 3PL, ERPNext no longer physically holds your stock — but it still needs to behave as though it knows exactly what is where. Native ERPNext gives you Warehouses, Stock Entries, Delivery Notes, Pick Lists and Sales Orders, but it has no built-in concept of pushing a confirmed order to ShipBob, ingesting an hourly inventory snapshot from Amazon MCF, or reconciling a partial shipment that a fulfillment center split across two boxes. Teams end up rekeying orders into a 3PL portal, exporting CSVs by hand, and discovering stock drift only when a channel oversells. That manual layer is where margin and customer trust leak out.

We build a proper Frappe app (its own module, installed via bench get-app/bench install-app) that turns your 3PL into a first-class ERPNext participant. Outbound, a hooks.py document event on Sales Order/Delivery Note submit — or a scheduler-driven queue for batching — maps the order to your provider's fulfillment schema and posts it through their REST API, recording the external fulfillment ID on a custom field. We model the integration with real DocTypes: a 3PL Provider settings DocType (credentials in encrypted Password fields, base URL, warehouse mapping child table), a 3PL Shipment Request log, and an ASN / Inbound Shipment DocType that drives a Purchase Receipt or Stock Entry when inventory physically lands at the fulfillment center. Inbound, a scheduler event (or the provider's webhook hitting a @frappe.whitelist() endpoint) ingests inventory feeds and reconciles on-hand quantities against the mapped ERPNext Warehouse, flagging discrepancies instead of silently overwriting. Tracking numbers, carrier, and status transitions are written back onto the Delivery Note and surfaced to the customer.

Multi-3PL routing is handled by a rules DocType you control from the ERPNext desk: route by item group, destination region, channel, or stock availability, with a deterministic fallback so an order never stalls. Every API call is idempotent and logged, retries use Frappe's background job queue with backoff, and failures raise a proper Error Log plus an optional Notification so ops sees them the same day rather than at month-end. Permissions are enforced through dedicated Role Profiles and DocType permissions so warehouse and finance users see only what they should, and client scripts add the desk-side buttons and status indicators your team actually uses.

Because this is build-to-order, nothing ships blind. We start with a scoping call to confirm which 3PLs, which channels, your ERPNext version (v15 or v16), and your exact reconciliation and routing rules. We build against your provider's live sandbox where one exists, deliver on a staging bench for UAT, and only then cut over to production with a rollback plan. Typical delivery is one working week from confirmed scope, depending on how many providers and edge cases are in play.