Inventory Module

Stock balance is not typed in anywhere. It is the running total of a signed stock ledger that the server appends to whenever a document with a non-zero quantity signum is finalised. Everything in this module either writes to that ledger, reads it, or prepares the paperwork around it.

Applets in this module

Membership is an editorial judgement — the product has no module↔applet relationship in its data — and it is written down in planning/specs/module-applet-membership.md rather than left to the folder each page happens to sit in. Inventory owns 22 applets and all 22 are documented.

Looking at stock

Moving stock

Asking for stock, and planning it

The warehouse floor

Getting it to the customer

Which documents actually move stock

A document moves stock only if its server document type carries a non-zero quantity signum. That number is fixed in the backend; it is not an applet setting, and the applet’s own copy of it is overwritten by the server on every save. Twenty-five document types have one.

    flowchart LR
  subgraph IN["Stock in (+1)"]
    PI["Purchase Invoice"]
    GRNSI["Purchase GRN <b>Stock In</b>"]
    SR["Sales Return"]
    SRN["Sales Refund Note"]
    TIN["Transfer In"]
    CGRN["Consignment GRN"]
  end
  subgraph OUT["Stock out (−1)"]
    SI["Sales Invoice"]
    CB["Cash Bill"]
    GINSO["Sales GIN <b>Stock Out</b>"]
    PR["Purchase Return"]
    TOUT["Transfer Out"]
    CGIN["Consignment GIN"]
  end
  ADJ["Stock Adjustment<br/>direction from the line"]
  CONV["Stock Conversion<br/>direction from the tab"]
  IN --> LEDGER[["Stock ledger<br/>bl_inv_txn_line"]]
  OUT --> LEDGER
  ADJ --> LEDGER
  CONV --> LEDGER
  LEDGER --> BAL["Stock balance<br/>item × company × location"]
  NONE["Sales Order · Purchase Order · Quotation<br/>Stock Requisition · Delivery Order<br/>Goods Delivery Note · Packing Order · Jobsheet<br/>Credit Note · Debit Note<br/>plain GRN · plain GIN<br/>Invoice No Stock In / No Stock Out"] -.->|"quantity signum 0"| NOTHING(["nothing reaches the ledger"])
  

What reaches the general ledger

Only one document this module owns posts a journal.

The general ledger is reached through exactly seven journal handlers in the whole product. The one this module uses is INTERNAL_STOCK_ADJUSTMENT; the cost of goods sold on a sale is posted by the sales handler, not by anything here.

Four things this module is often believed to do, and does not

A stock take does not adjust anything. It counts, it compares, it shows you a tolerance band and the cost of the difference — and it writes nothing to the balance. The gap is closed by a Stock Adjustment that somebody raises afterwards. There is no “post variance” button, and no shrinkage journal comes out of a count on its own.

There is no approval on a transfer, an adjustment or a count. BigLedger’s approval engine covers three document types — Purchase Order, Purchase Requisition and Stock Requisition — it is off until a tenant configures it, and it causes FINAL rather than gating it. Worse for this module: the Stock Requisition applet offers Approval Settings screens but has no approval tab on the document, no request screen and no history screen, so a setting created there has no effect today. Control transfers, adjustments and write-offs with permissions, not with an imagined workflow.

Stock Conversion does not re-allocate cost. It writes quantity and no value at all. An input line enters stock at zero value and drags the location’s moving-average cost down; an output line leaves at the running average. If you kit, expect the cost of the kitted item to be wrong and correct it with Reset Moving Average. Also read the tabs literally: Input means into stock, Output means out of stock, which is the opposite of what most people assume from a bill-of-materials tool.

Available is not “balance minus reservations”. It is the balance plus a signed adjustment for open documents, and the adjustment can be positive. Open sales orders push it down; goods received but not yet invoiced push it up. A location can show more available than it physically holds, and that is correct.

Costing

Every balance row carries moving average and weighted average cost, plus last purchase cost and landed cost; FIFO is written only where the FIFO/LIFO subscriber job is enabled and by the rebuild (LifoCostingHelper L74–L78 fills the FIFO columns). The LIFO, manual and replacement columns exist on the tables and are not maintained — nothing writes them (StockBalancePropertiesCalculator L88–L98 sets them null), and they are null on every ledger line in every tenant (aggregate, 2026-09-16). They are columns, not a mode you choose; each screen decides which one it shows.

In practice moving average is the one most screens use, and it is the one that bites:

• The Stock Take report values a variance at the location’s latest moving-average price. A FIFO tenant never sees FIFO cost there.
• A Stock Conversion input line enters at zero value and dilutes the average.
• A transfer never changes the company’s unit cost — the receiving location takes the company-level cost.

Reset Moving Average, in the Stock Adjustment applet, is how a wrong average is corrected. It changes inventory value on the balance sheet and cost of sales on the income statement, so restrict it to finance.

What this module needs from others

Where to go next