FIFO layer fields, statuses & enums

This page is the lookup for a FIFO layer — the costed batch of stock SKU.io creates every time inventory arrives — and for the revaluation ledger that records each change to a layer's cost. It defines every quantity, cost, and lot field on a layer; the columns you see on the FIFO layers list; the fields on a dated revaluation row; the availability lifecycle a layer moves through; the three enums that drive COGS sourcing, revaluation reasons, and layer allocation; and the guards that stop a layer from being written into an impossible state.

For the model behind these fields — how a layer is created, consumed, and how COGS is realized — read FIFO layers & how COGS is realized. For the difference between the three ways to change a layer's cost, read Correcting COGS: revalue vs rebuild vs recalculate.

Before you begin

• FIFO layers are derived, not entered. SKU.io mints and consumes them automatically as you receive stock, ship orders, transfer, and adjust. You never type a layer's quantities directly — you change them by adjusting stock, receiving a purchase order or transfer, or fulfilling an order, and the layer follows.
• The only fields you edit by hand are lot details (batch, expiry, notes) and a layer's cost, through Revalue COGS. Every cost change lands as a row in the revaluation ledger described below.

FIFO layer core fields

These are the quantity and cost fields on a FIFO layer. Two of them — Available quantity and Average cost — are database-generated columns: SKU.io computes them from the other fields and never writes them directly.

Field	Type	What it holds
FIFO layer date	date-time	The layer's cost-effective date — when the stock landed. Drives FIFO consumption order (oldest date first).
Original quantity	number	The quantity the layer started with when it was created. Never negative.
Fulfilled quantity	number	How much of the layer has been consumed. A cache reconciled from the layer's active negative movements; never negative, and never more than Original quantity (see Write guards below).
Available quantity	number (generated)	Remaining uncosted-out stock: Original − Fulfilled. A stored generated column — read-only, refreshed after every save.
Total cost	number	The layer's full landed cost for its original quantity.
Average cost	number (generated)	Per-unit cost derived from Total cost and quantity. A stored generated column; it's NULL until the layer is refreshed after a save, which is why internal cost snapshots use Total cost ÷ Original quantity instead.
Cost breakdown	map	A per-category landed-cost map (for example freight, duty, handling) that sums to Total cost. Sliced proportionally when a layer is split.
Cost version	number	Increments by one on every revaluation. The revaluation ledger chains on it (see The revaluation ledger row).
Condition	text	The stock condition pool the layer belongs to (for example sellable vs. a damaged pool).
Warehouse	link	The warehouse holding the layer. Can't be a supplier warehouse (see Write guards).
Consignment	yes / no	When yes, the layer holds supplier-owned stock — cost-carrying for later COGS but excluded from inventory valuation and GL reconciliation. Surfaced as Consigned in stock states.

Lot & expiry fields

A layer can also carry lot and expiry data, which drives FEFO (first-expiry-first-out) consumption, expiry reporting, and recall genealogy.

Field	Type	What it holds
Batch number	text	The lot identifier. Optional. When a lot-tracked positive event leaves it blank, SKU.io stamps an AUTO--prefixed fallback so every lot-tracked layer carries a batch for FEFO and recall.
Manufacture date	date	When the lot was produced.
Expiry date	date	When the lot expires. Drives FEFO ordering and the expiry buckets in demand planning.
Lot notes	text	Free-text notes about the lot.
Actual unit weight	number	The measured per-unit weight for the lot, when captured.

How a lot gets carved off a layer

When you stamp lot details onto stock that came in un-lotted, SKU.io preserves cost exactly using one of three paths: it merges into an existing matching lot, stamps in place when the whole layer is being lotted and nothing has been consumed, or carves a new lot layer off the source and reduces the source by the exact carved cost and a proportional slice of the cost breakdown (rounded to four decimal places). A blank batch is treated as distinct in the unique key, so un-lotted layers never collide. See FIFO layers & how COGS is realized.

FIFO layer list & detail fields

The FIFO layers list shows these columns; the layer detail view exposes the full field set below (the API resource behind both).

List columns, in order: ID, Date, SKU, Product Name, Warehouse, Original Qty, Fulfilled Qty, Available Qty, Avg Cost, Total Cost, Origin, Created, Updated.

Additional detail fields:

Field	What it holds
Days to expiry	A signed whole-day countdown to the expiry date — negative means already expired, null when the lot has no expiry. Computed date-only against your application timezone's "today".
Cost breakdown	The per-category landed-cost map (see core fields).
Origin	The polymorphic source that created the layer: its type (for example a purchase order receipt, transfer, adjustment, or manufacturing order), the linked record's ID, its human reference, and a parent reference where one exists. Rendered as a cross-linked chip with a tooltip showing the exact link type and ID.
Is FBA	Yes when the layer's warehouse is an Amazon FBA warehouse.
Is consignment	Yes when the layer holds consigned stock.
Condition	The stock condition pool.
Allocated quantity	How much of the layer is pinned to open orders (defaults to zero). See Browse allocations.
Archived at	The timestamp the layer was archived, or empty when active.

Available quantity in the list is recomputed

The list and detail views show Available quantity as Original − Fulfilled computed on read, rather than reading the stored generated column. The two always agree; the recompute just guarantees a value even on a row that hasn't been refreshed since its last write.

The availability lifecycle

A layer's availability is described by two independent axes — an availability state derived from its quantities, and an archived flag. The FIFO layers list filters on both.

Availability state (the Availability filter):

State	Meaning
Available	Has remaining stock: Original − Fulfilled is greater than zero.
Depleted	Fully consumed: Original − Fulfilled is zero or below.
Used	Has been drawn on at all: Fulfilled is above zero.
Unused	Never drawn on: Fulfilled is exactly zero.

Available and Used overlap on purpose — a partially consumed layer is both. Choose Available to find layers you can still ship from; choose Depleted to find spent layers.

Archived axis (the All / Active / Archived toggle): archiving a layer hides it from the default (Active) view without deleting its cost history. The toggle switches between all layers, active-only, and archived-only.

Empty layers can be archived — and un-archive themselves if refilled

A fully Depleted layer can be archived to tidy the list; its movement and cost history are kept. Archiving is reversible from the row's Unarchive action. A layer also auto-unarchives on save if it regains available quantity — so an archived layer that later receives stock back (for example a returned unit re-costed against it) quietly returns to the active view.

The revaluation ledger row

Every change to a layer's per-unit cost writes exactly one row to the revaluation ledger — the audit trail behind Revalue COGS and Rebuild COGS. Rows chain: each row's old unit cost equals the prior row's new unit cost, which is what makes point-in-time valuation and per-period GL reconciliation possible.

Field	What it holds
Cost version before / after	The layer's cost version immediately before and after the change. After always advances by one past before; the write is serialized under a row lock so two concurrent revaluations can't mint the same version.
Old total cost / new total cost	The layer's full cost before and after.
Old unit cost / new unit cost	The per-unit cost before and after. A revaluation is skipped entirely when the rounded per-unit cost is unchanged.
Units on hand at time	The layer's available quantity when the row was written.
Units consumed at time	The layer's fulfilled quantity when the row was written.
COGS source	The valuation source that set the cost — a CogsSource value.
Reason	Why the cost changed — an InventoryRevaluationReason value.
Reason notes	Free-text detail supporting the reason.
Effective at	The accounting date the change takes effect. Honors the accounting lock date: if the natural date falls in a locked period, SKU.io moves it to the first open-period boundary so closed books are never rewritten.
Posted at	When the row was actually recorded (defaults to now).
User	The user who made the change, when a person made it (empty for automated paths).

CogsSource enum

The COGS source records where a layer's cost came from. It's stored on each revaluation row and surfaced in the revalue UI and the SKU COGS Health dashboard. A source is either locked (backed by a document or an explicit user action, and treated as an actual cost) or editable (an estimate or fallback that automatic recalculation may update).

Value	Label	Sourced from	Cost
manual	Manual COGS Value	A user's explicit entry	Locked
purchase_order_line	Purchase Order Value	The purchase order line's landed cost	Locked
assembly_line	Assembly Line Value	The summed component costs of an assembly	Locked
warehouse_transfer_shipment_line_weighted_average_cost	Warehouse Transfer Shipment Line	The transfer shipment line's weighted average	Locked
sales_order_line_weighted_average_cost	Sales Order Line	The originating sales order line's weighted average (for a sales credit)	Locked
initial_fnsku_product_cost	Initial FNSKU Product Cost	An FNSKU product's seeded initial cost	Locked
awd_fifo_layer	AWD FIFO Layer	An Amazon AWD source layer	Locked
awd_pending_inbound	AWD Pending Inbound	An in-flight AWD inbound	Locked
oldest_active_fifo	Oldest Open Layer	The oldest still-available FIFO layer	Editable
newest_closed_fifo	Newest Closed Layer	The most recent fully consumed layer	Editable
unit_cost	Default Cost	The product's default unit cost	Editable
amazon_fifo_layer	Amazon FIFO Layer	An Amazon FBA source layer	Editable
amazon_weighted_average_cost	Amazon Weighted Average Cost	Amazon's reported weighted average	Editable
none	None	No cost source resolved yet	Editable

Three deprecated sources exist only on historic rows

weighted_average_cost_cache, any_fifo, and supplier_pricing are retained so old layers and ledger rows that carry them still render, but SKU.io no longer produces them when it picks a cost automatically. You will only ever see them on historic records.

InventoryRevaluationReason enum

The reason explains why a cost changed and rides on every revaluation row.

Value	Meaning	Set by
market_value_adjustment	The cost was adjusted to reflect current market value.	Manual revaluation
system_error	The cost is being corrected after a system or data error.	Manual revaluation
other	Another reason — detail it in Reason notes.	Manual revaluation
landed_cost_added	Landed cost (freight, duty, handling) was added after receipt.	Automated paths
vendor_invoice_correction	The vendor invoice corrected the cost after the fact.	Automated paths

The revalue form offers only three of the five reasons

When you revalue a layer by hand, the Revaluation Reason menu offers only Market Value Adjustment, System Error, and Other. landed_cost_added and vendor_invoice_correction are reserved for automated cost paths (landed-cost application and invoice corrections) and can't be chosen manually — so a hand revaluation you want to attribute to a late invoice should use Other with a note.

FifoLayerAllocationStrategy enum

When SKU.io distributes a consumption quantity across a product's available layers, it uses one of two strategies. FIFO is the default and the one that governs normal order fulfillment and adjustments.

Value	Behavior
fifo	Consume oldest layer first, walking forward by FIFO layer date until the quantity is satisfied. This is the default everywhere.
qty_match	Prefer a single layer whose available quantity exactly matches the needed quantity; otherwise pick the layer with the most total capacity. Used when moving an existing usage onto an alternative layer rather than consuming fresh stock.

Write guards

Two invariants are enforced whenever a layer is saved. Both raise an error rather than let a layer reach an impossible or nonsensical state.

Oversubscription guard. A save is rejected when Fulfilled quantity would exceed Original quantity (the layer would be consumed past what it holds), or when either quantity is negative. Because Fulfilled quantity is a cache reconciled from the layer's active negative movements, the cache-heal paths — which recompute it from the movements — are permitted to save with overage allowed so they can correct a drifted cache back into range. You can audit drifted or oversubscribed layers from the SKU COGS Health dashboard; the count of oversubscribed layers is one of its integrity signals.

Supplier-warehouse block. A layer can't be saved against a supplier warehouse — those warehouses model supplier-held stock you don't own, so they never carry owned FIFO cost. The save fails with a clear message naming the warehouse. This is also why manually receiving a channel-managed (Amazon FBA, AWD, or WFS) transfer is refused with an explanation rather than offered in the UI — that stock is costed through its channel path, not a manual owned-stock layer.

Next steps

• Browse & manage FIFO layers — find, filter, and archive layers.
• Revalue COGS (single, bulk & the COGS report) — change a layer's cost and write a ledger row.
• Rebuild COGS & the SKU COGS Health dashboard — repair drifted costs and caches in bulk.
• FIFO layers & how COGS is realized — the concept behind these fields.
• Correcting COGS: revalue vs rebuild vs recalculate — which correction to reach for.
• Stock states & fields reference — how layers roll up into on-hand, available, and consigned stock.