Lot & Serial Traceability + Recall Management

We build a proper Frappe app (ecosire_traceability) with its own module, DocTypes, and role profiles that sits on top of your existing Stock and Manufacturing data — it reads the ledger you already have, it does not fork it. The core is a genealogy engine that walks Stock Ledger Entry, Serial and Batch Bundle, Work Order, BOM, Stock Entry (manufacture/repack), Purchase Receipt, and Delivery Note links to build both directions of the tree: backward from a finished serial/batch to every consumed raw batch and its supplier lot, and forward from an incoming batch to every WIP and finished lot it touched and every customer shipment it reached. The walk is exposed through whitelisted server methods (@frappe.whitelist()) over the Frappe REST API so the trees render in a custom Trace Explorer page and can be pulled by external QMS/LIMS systems. A Recall Event DocType drives the one-click mock-recall: pick a suspect batch/serial, and a background job (enqueued via frappe.enqueue, not run inline) produces a Recall Impact Report — affected finished lots, on-hand quantity by warehouse, customer/delivery-note breakdown, and quarantine candidates — as a printable Print Format and CSV.

Technically it is wired in the Frappe-native way, not bolted on with brittle overrides. hooks.py doc_events on Stock Entry, Delivery Note, Purchase Receipt, and Quality Inspection maintain denormalized genealogy edges on on_submit/on_cancel so the tree query stays fast instead of re-walking the whole ledger each time. A Hold / Quarantine DocType with a controlled disposition workflow (hold → investigate → release/rework/scrap) writes Material Transfers to a quarantine warehouse and records disposition with full audit trail. Client Scripts add a "Trace this batch" action button on Batch, Serial No, Delivery Note, and Work Order forms. Scheduler events (scheduler_events hooks) can run periodic genealogy-integrity checks and expiry/recall-watch alerts. Everything respects Frappe permissions and role profiles — a dedicated Recall Manager role, quarantine-warehouse permission scoping, and full change tracking so the report itself is defensible in an audit.

Because this is build-to-order, nothing ships until we agree on scope. We start with a scoping call, map it to your actual BOM depth, batch/serial policy, warehouse layout, and which regulation you answer to, then build against a staging copy of your ERPNext (v15 or v16), run UAT with your quality team, and cut over with a rollback plan. Typical delivery is 2–4 weeks from confirmed scope. You receive the installable source for your version, a git repository handover, technical and user documentation, a training session, and a post-go-live support window — you own the code, and it is a real Frappe app you or another ERPNext partner can maintain.