Why fill rate decides everything in quick commerce
A healthy per-pack margin at 60% fill rate still loses the listing. How dark-store economics differ from marketplace economics, and what the algorithms actually reward.
6 min read
Quick commerce looks like a marketplace and behaves like retail distribution. Brands that treat it as another marketplace usually get the assortment right and the economics wrong.
The metric the platforms optimise for
Fill rate — the percentage of ordered units a dark store actually ships — is the number Blinkit, Zepto and Instamart reward and penalise on. Availability drives velocity, velocity earns shelf space in a store that has very little of it, and a listing that goes out of stock repeatedly is de-prioritised or delisted.
This inverts the usual marketplace instinct. On Amazon, a wide catalogue with occasional stockouts is survivable. In a dark store with a few thousand SKUs and no back room, an unreliable SKU is a liability to the store, and it is treated as one.
The margin stack is different too
A quick-commerce P&L per pack typically absorbs:
- the platform margin taken off MRP,
- promotional co-funding, often non-negotiable during platform-wide events,
- visibility and ad spend to hold position,
- listing or slotting charges,
- wastage and expiry on perishables.
Then the whole contribution is multiplied by fill rate. A pack contributing ₹18 at 95% fill contributes ₹17.10; the same pack at 60% fill contributes ₹10.80 — and is simultaneously losing the ranking that produced the orders.
What to do about it
Design pack architecture for dark-store shelf space rather than for marketplace price points, forecast replenishment against store-level velocity, and model the terms before signing them. Our Quick Commerce Margin Model computes the fill-adjusted contribution so the two halves of the problem are visible together.
Platform-by-platform onboarding, assortment, pricing and growth for Blinkit, Zepto, Instamart and BigBasket are covered in the Quick Commerce Playbook.