Market-making quoter

A market maker posts bids and asks on both sides of a fair price and earns the spread when both fill. Doing that well means more than placing one bid and one ask. The quotes step out across several levels, they lean against the position the maker is already carrying, and they hold still through small price moves instead of churning the book. Quoter packages that into a reusable primitive so a strategy does not rebuild it each time.

The ladder

Given a fair price, the quoter produces a ladder: a set of bid levels and a set of ask levels, each a configured size. The first level sits a target half-spread away from the price, and each further level steps out by a fixed amount. A wider ladder captures more flow at worse prices; a tighter one fills more often near the top.

Inventory skew

A maker that keeps buying ends up long and exposed. To lean against that, the quoter shifts a reservation price away from the fair price in proportion to the current inventory. A long position pulls the whole ladder down, so the asks become more attractive and sells fill first; a short position pulls it up. With no inventory or no skew configured, the reservation price is the fair price and the ladder is symmetric.

Holding quotes steady

Re-quoting on every tick burns through order operations and queue priority for no gain. shouldRequote answers whether a resting quote has drifted far enough from its target to be worth replacing, measured in price ticks. A strategy uses it to hold quotes through small moves and only cancel-replace when the price has moved past a tolerance.

What the strategy still owns

The quoter computes the desired quotes. It does not place them. Reconciling the ladder with live orders, deciding what to cancel, what to modify, and what to leave, stays with the strategy, which is where the order ids and the venue rules live. The toolkit is the math a maker would otherwise write by hand, not a replacement for the strategy's own order management.