Read-only Quoting

Overview

MAOB is designed to be quoted offchain using a combination of:

• oracle mid price (getMidPrice)
• rung configuration (getRungs, rungCount)
• live liquidity depth (getDepth, getRungState)
• per-order claimability (previewOrder) for maker UX

This page describes practical patterns for quoting and choosing taker guardrails.

Reading market state

Mid price

Use:

• getMidPrice() -> (price, precision, updatedAt)

If updatedAt is stale relative to your own policies, you should refuse to quote.

Rungs

Use:

• getRungs() to read the configured bps offsets.
• Interpret bps as 0.1 bps units (denom 100_000).

Depth

Use:

• getDepth(maxPerSide) to fetch up to maxPerSide non-zero rungs per side.

Returns:

• ask rung bps values + volumes (base token units)
• bid rung bps values + volumes (quote token units)

This is a “summary” view (closest rungs first by rung index scan) and is often enough for UI depth and rough quoting.

Per-rung detailed state

Use:

• getRungState(rung) to read volumes and generation/cumulative fill values.
• getLastSegment(rung, isAsk) for debugging or advanced inspection.

Other parameters to fetch

For accurate quotes and guardrails, you will also want:

• takerFee() + FEE_DENOM() to compute taker fees.
• minQuoteTaker() for minimum notional checks.
• takerPaused() to avoid quoting when takers are paused.
• maxStaleSeconds() to mirror MAOB's oracle staleness policy (if non-zero).
• RUNG_DENOM() and PRICE_SIGFIGS() to match price math and rounding.

Choosing taker guardrails

maxRung

maxRung controls how far from the midpoint you will cross. A common approach:

• choose a rung limit based on acceptable slippage from mid
• quote a price impact using depth
• set maxRung to the furthest rung needed

deadline

Set a short deadline to reduce the risk of stale offchain quotes being executed after market conditions have changed.

• deadline == 0 disables checks (generally not recommended for UI trading flows)

Slippage parameters

• For buy exact out: set maxQuoteIn
• For buy target in: set minBaseOut
• For sell target in: set minQuoteOut
• For sell exact out: set maxBaseIn

Minimum quote checks (minQuoteTaker)

MAOB enforces a minimum quote notional. For quoting:

• Buy exact out & sell target in: the check is against the midpoint value of baseAmount (rounded with PRICE_SIGFIGS).
• Buy target in & sell exact out: the check is against quoteIn / quoteOut directly.

Onchain previewing (MAOBPreviewer)

MAOBPreviewer is a stateless view helper that simulates MAOB taker fills against live state. It mirrors MAOB rounding, remainder carry, taker fees, and guardrails. Use it via eth_call to get an exact quote before submitting a transaction, or to validate an offchain simulator.

Each function has a maxRung overload; the version without maxRung traverses all rungs (maxRung = rungCount - 1).

• previewBuyBaseExactOut(maob, baseAmount, maxQuoteIn, maxRung) -> (quoteUsed, baseFeePaid, baseOut)
• previewBuyBaseTargetIn(maob, quoteIn, minBaseOut, maxRung) -> (baseOut, baseFeePaid, quoteUsed)
• previewSellBaseTargetIn(maob, baseAmount, minQuoteOut, maxRung) -> (quoteOut, quoteFeePaid, baseUsed)
• previewSellBaseExactOut(maob, quoteOut, maxBaseIn, maxRung) -> (baseUsed, quoteFeePaid, netQuoteOut)

Notes:

• baseAmount and quoteIn are pre-fee inputs; baseOut / quoteOut outputs are after fee.
• For previewSellBaseExactOut, quoteOut is net (after fee); the previewer computes the gross quote required and then applies fees.
• Previewer checks takerPaused, maxStaleSeconds (oracle staleness), and minQuoteTaker the same way MAOB does.

Failure modes to expect (previewer reverts; surface these in UIs):

• MAOB__InvalidAmount(), MAOB__InvalidRung()
• MAOB__TakerPaused()
• MAOB__OraclePriceMissing(), MAOB__OracleStale(), MAOB__OracleOutOfRange()
• MAOB__InsufficientLiquidity()
• MAOB__MaxQuoteExceeded() / MAOB__MaxBaseExceeded()
• MAOB__MinBaseNotMet() / MAOB__MinQuoteNotMet() / MAOB__QuoteAmountTooLow()

Notes on precision and rounding

MAOB rounds internal priceQ to a fixed significant-figure configuration. This means:

• exact offchain simulation is possible but must match rounding behavior
• small trades can be affected by rounding “dust”

The previewer uses getLastSegment(rung, isAsk) to carry per-rung remainder state on the ask side. If you simulate offchain, you must incorporate this remainder logic; otherwise, your quote may be slightly optimistic or pessimistic.

For critical integrations, prefer conservative slippage buffers.