Inventory
Available stock is on-hand minus reserved. Nothing can sell what's already promised.
Oneop's warehouse layer treats that subtraction as an invariant, not a display formula. Every reservation takes a database row lock, recomputes available, and refuses the request if the number would go negative. Two orders hitting the last unit at the same instant cannot both succeed.
Multi-warehouse, bin-level locations, lot and batch tracking, transfers, cycle counts, purchase orders with landed cost, sales orders, picking, shipment and RMAs — all on the same records your CRM and support desk already use.
No credit card. Free plan, 2 seats, 20 products, 1 warehouse.
Three things that are true here and rarely true elsewhere
Overselling is prevented by arithmetic under a lock, not a nightly job
reserveStock() opens a transaction, runs SELECT on_hand, reserved … FOR UPDATE on the stock row, computes available = on_hand − reserved, and throws WH_RESERVE_FAIL if the requested quantity exceeds it. The lock serialises concurrent reservations, so two requests cannot both read the same availability and both succeed. Shipping is capped at the line's own reservation, so fulfilling one sales order cannot consume stock another order already holds.
Nine carrier integrations against real carrier APIs
Three aggregators — EasyPost, Shippo and ShipStation — plus FedEx, UPS and USPS direct, plus TCS, Leopards Courier and PostEx for the Pakistan market. You connect your own carrier accounts, compare live rates and buy real labels with tracking numbers.
Reorder points that agree with themselves
A reorder point can be set per item or overridden per warehouse. The stock view resolves one effective threshold — the warehouse override when set, otherwise the item-level value — so the stock page, the products page and low-stock alerts never disagree about when to reorder.
Receiving → reservation → pick, pack, ship
Stock moves through four states and each transition writes a movement row.
Receiving is partial-safe
Each line tracks ordered against already-received and refuses to over-receive. A zero-cost receipt is rejected outright — it would book zero COGS on sale.Reservation shares the order's transaction
Confirming a sales order reserves stock inside the same transaction as order creation — a failure halfway through rolls both back, no orphaned holds.Pick, pack, ship is one transaction
Stock decremented, COGS posted, shipment and invoice written, status advanced — a crash anywhere rolls all of it back.Returns run their own lifecycle
Available Pro and above, as its own reversible sequence.
Carriers, rates and labels
Oneop connects to nine carriers and fails closed when it is not configured correctly.
- Rates come from the carriers you connectRate shopping calls each connected carrier and returns its own live quote. Buying a label is idempotent under a row lock — a duplicated click can't buy a second label.
- Fails closed, never guessesRating and label purchase both refuse to run until your ship-from origin is set — no silent default, no mis-rated label.
Demand forecasting — statistical, not AI
Holt's double exponential smoothing over your historical issue movements — 91 days back, projected 8 weeks forward. That is statistics, not a language model, and we would rather say so. The only genuinely AI capability that touches stock is the reorder agent, gated exactly like the flow on the right.
On-demand runs skip the sweep entirely — always available.
How stock ties to invoices and the ledger
Shipping posts cost of goods sold to a real general ledger in the same transaction that decrements stock — never a display formula reconciled later.
- Invoicing is deferred to shipmentPurchase-order receipts create the AP bill. For inventory orders you never invoice goods that haven't left the building.
- Finance ships in every workspaceA real double-entry ledger with a Postgres trigger that refuses an unbalanced entry — every plan, including Free. See how the ledger works.
- Stock connects sideways tooA sales order starts from a CRM quote, and the account record shows every quote, order and invoice with drill-down. See CRM.
Ship — one transaction
A crash anywhere rolls all three back — never a partial ship.
Void the invoice — the mirror, also one transaction
What it costs
Inventory is included on every plan, including Free, with per-plan limits.
Annual billing is two months free. Extra seats are $5 per seat per month. Full ladder and current numbers on pricing.
See full pricing| Plan | Products | Warehouses | Purchase orders | RMAs · serial & lot |
|---|---|---|---|---|
| Free | 20 | 1 | — | — |
| Starter — $19/mo | plan limit | plan limit | ✓ | — |
| Pro — $59/mo | plan limit | plan limit | ✓ | ✓ |
| Business — $129/mo | plan limit | plan limit | ✓ | ✓ |
Frequently asked
How does Oneop stop two orders from selling the same last unit?
Reservation takes a row-level database lock on the stock row before it reads availability. The first request locks the row, computes available = on-hand minus reserved, reserves, and commits. The second request blocks until that commit, then reads the updated numbers and is rejected with an insufficient-stock error. The check and the write are not separable, which is what makes the guarantee hold under concurrency.
Do I have to turn inventory on?
No. Inventory, warehouses and fulfilment are on from day one, on every plan including Free — there is no module to switch on. Finance, which is where stock movements post as COGS, ships in every workspace too; deeper accounting depth is a Pro-and-above plan feature. The one genuinely opt-in piece here is the automatic daily reorder sweep — on-demand runs are always available, and we switch on the sweep for your workspace on request.
Is the demand forecasting AI?
No, and we will not call it that. It is Holt’s double exponential smoothing — a standard statistical method with level and trend components — fitted to your historical issue movements. No language model is involved. We think naming the method is more useful than the label.
Which carriers can I use?
Nine: EasyPost, Shippo and ShipStation as multi-carrier aggregators, FedEx, UPS and USPS directly, and TCS, Leopards Courier and PostEx for Pakistan. You connect your own carrier accounts, so you keep your negotiated rates.
How does stock connect to accounting?
Shipping posts cost of goods sold as a double-entry journal entry inside the same transaction that decrements stock, so the two can never disagree. Receiving a purchase order creates the accounts-payable bill. Voiding an invoice reverses the ledger entry and releases the stock reservation. Finance, where those entries land, ships in every workspace on every plan; deeper accounting depth is Pro and above.
See it against your own stock.
Start on the free plan with 20 products and one warehouse, or book a walkthrough and we will show you the reservation lock, the ship transaction and the ledger posting in the product.
Sign-up opens when the app launches. We will email you once — no marketing list.