> ## Documentation Index > Fetch the complete documentation index at: https://docs.0xmonaco.com/llms.txt > Use this file to discover all available pages before exploring further. # Self-Trade Prevention > Choose what happens when an incoming order reaches your own resting order. export const LearnStyles = () => { useEffect(() => { const revealReference = () => { let id; try { id = decodeURIComponent(window.location.hash.slice(1)); } catch { return; } if (!id) return; const target = document.getElementById(id); if (!target) return; let opened = false; for (let parent = target.parentElement; parent; parent = parent.parentElement) { if (parent.tagName === "DETAILS" && !parent.open) { parent.open = true; opened = true; } } if (opened) target.scrollIntoView({ block: "start" }); }; const frame = requestAnimationFrame(revealReference); window.addEventListener("hashchange", revealReference); return () => { cancelAnimationFrame(frame); window.removeEventListener("hashchange", revealReference); }; }, []); return ; };
Self-trade prevention (STP) applies across your **wallet family**: accounts sharing your wallet address, including across applications. Those accounts cannot trade with one another. A sub-account registered under a different wallet address belongs to a separate family. The incoming order’s mode governs the match. By default, Monaco cancels your resting order and continues matching the incoming order against other liquidity. ## Choose A Mode | Mode | Your resting order | Your incoming order | | - | - | - | | Cancel maker · default | Each of your resting orders reached by the incoming order is cancelled in full. | Continues against other liquidity. | | Cancel taker | Remains untouched. | Any earlier third-party fills stand; the remainder cancels at the first self-touch. | | Cancel both | Every resting order it would have reached is cancelled. | Its remaining quantity is cancelled. | | Skip | Remains untouched and is never matched. | Trades around your orders. A remainder that would rest crossing your surviving order is cancelled. |
Default behaviorYour incoming buy reaches your own resting sell

The resting sell is cancelled. The buy continues looking for other liquidity. The two orders do not trade with one another.

## Which Setting Applies? The priority is: 1. The mode specified on the incoming order. 2. Your configured wallet default. 3. The platform default: **Cancel maker**. A replacement is a new order, so its mode must be specified again to retain a per-order setting. Wallet defaults apply to every order in the family that does not specify a mode. ## Exceptions To Understand * **FOK can still remove your quotes.** Under Cancel maker, your own quotes are cancelled before the third-party depth check. If the FOK cannot fill, those cancellations can still stand. * Under **Cancel taker or Skip**, a self-cross in the fill path cancels the whole FOK. FOK with **Cancel both** and a self-cross is rejected at placement. * A zero-fill market order refused before sequencing does not commit a simulated maker cancellation. Do not infer a quote was removed solely from the incoming order’s failure. * **Post-only** orders reject if they would cross before STP is consulted, regardless of who owns the opposing liquidity. * **Liquidations and auto-deleveraging** do not apply STP. A liquidation slice fills against your own resting orders in other risk buckets and sub-accounts in price order, like anyone else's, and never cancels them; ADL fills no resting orders and can close an opposing position in your other risk buckets. User settings cannot obstruct either. ## Identifying A Prevented Trade STP cancellations carry a self-trade-prevention reason and the counterparty order ID. They have cancelled status, which differs from accepted zero-fill IOC/FOK rejections for insufficient qualifying liquidity. The full reference preserves the exact status, event, movement-channel, and configuration fields for integrations. Self-trade prevention (STP) decides what happens when your incoming order would match one of your own resting orders. Most venues fix a single behavior — typically cancelling the resting order — or offer a limited subset. Monaco exposes **all four behaviors**, selectable per order and configurable as a default per wallet: | Mode | What happens at a self-cross | | - | - | | `CANCEL_MAKER` | Every resting order of yours the incoming order reaches cancels in full; the incoming order keeps matching against other liquidity. **The platform default.** | | `CANCEL_TAKER` | The incoming order fills third-party liquidity ahead of your order, then its remainder cancels at the first touch of your own order — liquidity behind it is never reached. Your resting order is untouched. | | `CANCEL_BOTH` | The incoming order's remainder cancels **and** every one of your resting orders it would have reached cancels. | | `SKIP` | The incoming order trades *around* your resting orders — they are never matched and never cancelled. A remainder that would rest crossing one of your own surviving orders cancels instead of resting. | `SKIP` in particular is rare among venues: it lets a market maker's incoming flow coexist with its own quotes instead of destroying them.

How it resolves

* **The incoming (taker) order's mode governs the whole match.** Modes carried by resting orders are never consulted — the same convention as every major venue. * **"Your own" means your wallet family**: every account under your wallet address, across applications, including every margin sub-account you open (they all belong to your user). Two accounts under the same wallet address cannot trade with each other. A master-account sub-account linked under a different wallet address is its own family. * **Resolution order**: the order's own `selfTradePreventionMode` field if present → your wallet's configured default → the platform default (`CANCEL_MAKER`). * Orders cancelled by STP are announced like any other cancellation, with `terminalReason: SELF_TRADE_PREVENTION` on the WebSocket event and on later order reads; the event also carries `stpCounterpartyOrderId` identifying the order on the other side, so the cause is always attributable. * An STP outcome is a **`CANCELLED`** order even when nothing filled — deliberately distinct from an accepted zero-fill `IOC`/`FOK`, which is `REJECTED` for want of qualifying liquidity — for a `FOK` that means depth that cannot cover the full quantity, whose candidate fills are then discarded, not necessarily an empty book. (A plain zero-fill `MARKET` submit never reaches either outcome: it is refused before acceptance and emits no order event.) Status alone separates "my own prevention ended this" from "there was not enough qualifying liquidity", with no message parsing. * A swept **spot** maker also receives the movements-channel `user_movement` frame for its lock release, exactly as a user-initiated cancel produces. A swept **margin** maker receives none: its reserve release moves no `user_balances` leg — and a user cancel of a margin order emits none either, so the two stay consistent. Do not wait on a movements frame for a margin order.

Setting it

* **Per order**: pass `selfTradePreventionMode` on create, replace, or batch items. A replacement is a new order — restate the field to keep it. * **Per wallet**: [`GET`](/api-reference/accounts/get-self-trade-prevention-default)/[`PUT /api/v1/accounts/self-trade-prevention`](/api-reference/accounts/set-self-trade-prevention-default) reads and sets your wallet's default (applies to every order from your wallet family that names no per-order mode).

Edge semantics worth knowing

* **Fill-or-kill**: under `CANCEL_TAKER` or `SKIP`, any self-cross in the fill path cancels the whole FOK; under `CANCEL_MAKER`, your makers cancel first and the order then fills or kills against the rest; a `FOK + CANCEL_BOTH` order with a self-cross in its fill path is rejected at placement with `SELF_TRADE_NOT_ALLOWED` — all-or-none contradicts the partial outcomes `CANCEL_BOTH` produces. * **A killed `FOK` still cancels your makers.** Under `CANCEL_MAKER` the sufficiency check runs on third-party depth only — your own orders are cancelled first and never counted as available liquidity. If that depth cannot fill the order the `FOK` is rejected *and* those cancellations stand: you lose the quotes and get nothing. (`FOK` is a `LIMIT`-only time in force — a `MARKET` order carrying any `timeInForce` is rejected outright.) * **A rejected taker does not mean your quote was swept.** The cancellation is decided during simulation and commits only if the order is sequenced. A zero-fill `MARKET` order whose only in-band depth was your own resting order is rejected for insufficient liquidity **before the sequence is allocated**, so the simulated cancellation is discarded and your resting order survives. Reconcile against the order stream rather than inferring from the taker's result. * **Post-only orders** reject with `POST_ONLY_WOULD_CROSS` before STP is ever consulted, whoever owns the crossing liquidity. * **Liquidations and auto-deleveraging** apply no self-trade prevention at all, whatever your configured mode. A liquidation slice matches your own resting orders — from your other risk buckets and sub-accounts — in price order exactly as it matches anyone else's, counts them as available depth, and never cancels them for crossing. ADL does not trade against the book: it closes opposing positions directly at the pinned price, and a position your other risk buckets hold is as eligible as anyone else's. It never fills your resting orders, but when it fully closes a position, that risk bucket's resting reduce-only orders on the pair are cancelled with terminal reason `AUTO_DELEVERAGING`. User configuration can never impede a forced close. (The liquidated risk bucket's own resting orders are cancelled before it is liquidated, with terminal reason `LIQUIDATION`.)
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