Current versions: testnet runs
testnet-v1.3.9, mainnet runs a build that includes all changes through testnet-v1.3.1. Entries are anchored to the testnet release that first shipped each change.testnet-v1.3.9
Breaking changes
Deprecated*Bps fee-tier aliases removed. The makerFeeBps/takerFeeBps fields on GET /v1/feetiers, GET /v1/account/stats, and feeTierConfig entries on exchangeAttributeUpdates — along with the spot schedule’s maker_fee_bps/taker_fee_bps — are gone, completing the ppm rename announced in testnet-v1.2.31. Use makerFeePpm/takerFeePpm (and maker_fee_ppm/taker_fee_ppm); the values are unchanged.testnet-v1.3.8
New features
Orderbook price aggregation.GET /v1/l2OrderBook/{market} and the l2Orderbook channel accept an optional sigFigs (2–5) to bucket price levels to that many significant figures, plus roundStep (1, 2, or 5) to refine the finest bucket when sigFigs is 5. Bids round down and asks round up so the displayed spread is never tighter than the true book, merged sizes are summed, and aggregation is applied before nLevels truncation. Omit sigFigs for full precision.Updates
Order-size bounds on markets.GET /v1/markets and the markets channel add minOrderSize and maxOrderSize (base-asset units). maxOrderSize is a per-order security gate rather than a dust filter — reduce-only orders are not exempt.testnet-v1.3.7
New features
Invite codes. Two new referral endpoints:GET /v1/affiliate/inviteCodes lists the codes an account has earned (one per $1M of lifetime perps volume) with redemption status, and POST /v1/affiliate/redeemInvite redeems a single-use code — binding the caller as a referee of the code’s owner and granting perps trading access. Unlike the other affiliate reads, inviteCodes is signed (with no body its message is X-Timestamp + ACTION): invite codes are bearer secrets, so possession of the API key’s private key is required.Updates
Explicit RTH-transition events on marketAttributes. ThemarketAttributes channel’s boundEvent adds exitRth / enterRth for Regular Trading Hours boundary crossings, and is now present on every delta entry — only snapshots omit it. boundSide is likewise always present on deltas (null on RTH transitions and VWAP seals).Portfolio PnL rebased per timeframe. pnlHistory on GET /v1/portfolio now rebases each timeframe so its first point is 0 — every point is the trading + funding PnL earned since the start of that timeframe, and lifetime PnL is the last point of the all timeframe. The curve still does not jump on deposits or withdrawals.testnet-v1.3.6
New features
Off-hours market attributes over WebSocket. NewmarketAttributes channel streams per-market Regular Trading Hours / off-hours trading-band state for every online market — isOutsideRth, the sealed currentSettlementPrice anchor, both current trading-band edges and their next-level edges, and per-side expansion-zone state with its clocks. It is a global channel (no id): a full per-market snapshot on subscribe (isSnapshot: true), then a single-market update on each RTH boundary crossing, VWAP seal, and off-hours bound event — each carrying that market’s complete post-event block plus a timestamp and marketSequenceNum. Fields that do not apply are null (24/7 crypto markets are included with isOutsideRth: false and all band fields null). Supersedes the marketAttributes entry variant on exchangeAttributeUpdates.Documentation
Updates
Docs default to mainnet. The API playground and the curl / Python / JavaScript code samples throughout the API reference now target the production host —https://api.arcus.xyz (REST) and wss://api.arcus.xyz/v1/ws (WebSocket) — instead of testnet. Testnet (api.testnet.arcus.xyz) remains fully available and is still selectable from the server dropdown on every endpoint and channel page; the two environments share identical paths, payloads, and signing, so a sample runs unchanged against either by switching the host. This supersedes the earlier note (below) that samples and the playground targeted testnet.testnet-v1.3.5
Updates
Forced closures are marked on fills. Fill rows add aliquidation object — method (LIQUIDATION or ADL) plus liquidatedUser — present on the liquidated account’s leg of a liquidation and the deleveraged counterparty’s leg of an auto-deleverage; absent on voluntary fills. The marker is persisted, so GET /v1/fills and userFills snapshots return it too, and it is the supported way to detect forced closures (the liq: order-ID prefix is an internal detail). On the liquidated leg, fee carries the liquidation penalty paid to the insurance fund and closedPnl reads "0" by design — the realized loss is already reflected in netQuoteBalance on the accompanying account update.testnet-v1.3.3
New features
Account transfer events over WebSocket. NewaccountTransferUpdates channel streams deposits, withdrawals, internal transfers, and referral claims for an account: a newest-first snapshot on subscribe, then one event per transfer as the engine applies it. Amounts are decimal strings in quote currency, and globalSequenceId gives strict ordering. The REST equivalent is GET /v1/accountTransferUpdates.Predicted funding over WebSocket. New predictedFunding channel streams the predicted next-hour funding rate per market as a {market, rate1h} payload, refreshed each time the funder recomputes the prediction. Unlike most channels, payloads are not wrapped in an isSnapshot envelope.Updates
Subaccount selector on all account-scoped reads. The optionalaccountIndex query parameter (0–9, default 0) previously accepted only by GET /v1/fills now applies across account-scoped endpoints: GET /v1/account, /v1/positions, /v1/openOrders, /v1/orders, /v1/order/{orderId}, /v1/funding, /v1/accountTransferUpdates, /v1/portfolio, /v1/rateLimit, /v1/leverages, and /v1/apiKeys. Values above 9 return 400.Faster orderbook snapshots. The l2Orderbook full-snapshot cadence tightened from ~500 ms to ~200 ms.testnet-v1.3.1
Updates
24-hour high/low on markets.GET /v1/markets and the markets channel add high24h and low24h — highest and lowest transaction price over the trailing 24-hour window, computed from closed 1-minute candles with at least one trade and omitted when no trades occurred in the window.testnet-v1.2.31
Updates
Fee-tier fields renamed to ppm.makerFeeBps/takerFeeBps become makerFeePpm/takerFeePpm in the fee-tier shape returned by GET /v1/feetiers, GET /v1/account/stats, and feeTierConfig entries on exchangeAttributeUpdates; the spot fee schedule likewise renames maker_fee_bps/taker_fee_bps to maker_fee_ppm/taker_fee_ppm. The values were always parts-per-million despite the old names. The *Bps fields remain as deprecated aliases (identical values) for one release cycle — migrate to the *Ppm names now.testnet-v1.3.0
Breaking changes
Testnet withdraw/transfer signing domain rotated. The July 22 testnet reset rotated theBridgeVault verifyingContract for POST /v1/withdraw and POST /v1/transfer to 0x9a6d3499149fea853efe775a3577701539054eaf; signatures against the previous address are rejected with 401. This address rotates on every testnet reset — read the current value from the withdraw endpoint’s per-environment table. The funding guide contract addresses rotated in the same reset.Updates
Perp candle timestamp bounds declared in the schema.GET /v1/candles from/to (Unix microseconds) now declare minimum: 1e14, matching what the handler always enforced.testnet-v1.2.6
Updates
API key create/revoke signing migrates to EIP-712.POST /v1/createApiKey and POST /v1/revokeApiKey are now authenticated by an EIP-712 typed-data signature (eth_signTypedData_v4) instead of an EIP-191 personal_sign. Both schemes are accepted during the migration window; EIP-191 is deprecated and will be rejected once the window closes. Always send validUntil explicitly and sign that value — omitting it makes the server verify against its own default. See each endpoint description for the domain, types, and signing examples.Spot candle timestamp bounds declared in the schema. GET /v1/api-meta/candles from/to (Unix seconds) declare the [1, 1e11) window, rejecting millisecond-scale values.testnet-v1.2.3
New features
Internal transfers between subaccounts. NewPOST /v1/transfer moves collateral between two account indexes of the same wallet — in v0 there is no cross-wallet recipient. The request is signed with an EIP-712 typed-data signature over the Transfer payload (eth_signTypedData_v4) and carries a single-use nanosecond-timestamp nonce for replay protection (a repeated nonce returns 409). amount is a quote-quantum integer string (1e9 = $1); unlike withdrawals it never settles on-chain, so it is not constrained to collateral-base-unit multiples. Acceptance is asynchronous: the response carries status: PENDING and a transferId, with the terminal outcome delivered on the account transfer update stream — insufficient free collateral rejects there with REJECTED_INSUFFICIENT_COLLATERAL.Per-market open-interest caps. GET /v1/markets and the markets WebSocket channel add openInterestCap — the operator-set maximum open interest as a USD-notional decimal string (present only while a cap is active). While a market is at its cap, the engine rejects OI-increasing fills with the new rejection reason OPEN_INTEREST_CAP_EXCEEDED; OI-neutral and OI-reducing trades (closes, and opener-vs-closer pairings) still match. Fills executed before the halt stand, and the cap clears as open interest falls or the operator raises it.Updates
Signed withdrawals are single-use.POST /v1/withdraw now rejects a replayed (ethereumAddress, accountIndex, nonce) with 409 — resubmitting an identical signed body (or any body reusing the same nonce) no longer queues a second withdrawal. Use a fresh nonce for each new withdrawal; the recommended nonce is the current time in nanoseconds since the Unix epoch.testnet-v1.2.2
Updates
API keys are scoped to(address, publicKey). An Ed25519 public key is globally unique across accounts: POST /v1/createApiKey returns 409 Conflict when the publicKey is already registered to a different account (including expired-but-unrevoked keys), and only the owning account may register or renew it. POST /v1/revokeApiKey returns 404 when the key is not registered to the caller’s account — including cross-account revoke attempts — with no side effects.testnet-v1.2.1
New features
Sectioned account stats.GET /v1/account/stats is now sectioned so clients fetch only what they need via the include query parameter: feeTier (the current fee tier — cheap, right shape for frequent fee-rate polling) and volumes (notional fill volume and fees paid over the 14-day fee-tier rolling window and all-time — backed by analytics storage, fetch on demand). The volumes section also accepts opt-in fixed windows via windows=24h,7d,30d.Market filter on fills. GET /v1/fills adds an optional market query parameter to restrict fill and trade history to a single market, alongside the existing from/to time bounds and accountIndex subaccount selector.testnet-v1.2.0
Breaking changes
Withdraw EIP-712 signing domain rotated; production domain published. TheBridgeVault verifyingContract for POST /v1/withdraw changed on staging (0xfcb43af23e80dbbe7d951af49aa4eefb4eff8c2c) and testnet (0x317253c5c134c3ac60e84c4ca069c9f588030480) — withdrawal signatures produced against the previous addresses are rejected. The production domain is now published: chainId 4663, verifyingContract 0x14b107cf534239c59571b066cb6497a321da897c.Updates
Modify order is no longer marked “coming soon”. The stale caveat claimingPOST /v1/modifyOrder returns 501 Not Implemented is removed — the endpoint has been live for some time. The docs now also spell out the queue-priority contract: a modify is applied in place (keeping queue priority) only when it leaves the price unchanged and reduces size; any price move or size increase is an atomic cancel + replace that loses priority. On the orders WebSocket channel a non-crossing modify arrives as a single update; a crossing modify arrives as a fill followed by a PLACED (or REJECTED) — no separate cancel/place event pair is emitted.goodTilTime is required on every order — the schema now says so. The order schema previously required goodTilTime only for resting time-in-forces (GTT, ALO) and described it as “ignored” for IOC/FOK; the API has always rejected orders without it. It is now documented as unconditionally required on POST /v1/placeOrder, the batch variants, and the WebSocket order payloads: for IOC/FOK it acts as a mandatory replay-protection timestamp, and it must be at least one month in the future.Time-in-force: submit GTT, read GTC. Order submissions must use GTT (Good Till Time) for resting orders, but order reads — REST order queries and the orders WebSocket channel — currently report resting orders as GTC, the legacy name for the same bucket. A new TimeInForceResponse schema documents the read-side enum; treat GTC and GTT as equivalent when reading.modifyOrder signing payload documented in full. The typed canonical payload for modifyOrder now shows its complete field set — {"ad","ai","c","ct","g","id","m","op":3,"p","q","r","s","t","v"}. id is always required, and g/r/s/t echo the resting order’s goodTilTime (in nanoseconds), reduceOnly, side, and time-in-force. The modify request body now also requires reduceOnly and goodTilTime to be echoed explicitly (a differing goodTilTime performs a cancel-replace with the new expiry).Subaccount authorization on order writes. The 403 responses on POST /v1/placeOrder, POST /v1/cancelOrder, the batch variants, and POST /v1/modifyOrder now also cover the case where accountIndex does not match the API key’s authorized subaccount.testnet-v1.2.0
Breaking changes
Off-hours trading-band fields reshaped. OnGET /v1/markets and the markets WebSocket channel, the off-hours band is now reported as actual USD price boundaries rather than multiplier strings. currentTradingBound / nextTradingBound are removed; use upperTradingBound / lowerTradingBound (plus nextUpperTradingBound / nextLowerTradingBound) and the new per-side expansion-zone state — isUpperInExpansionZone / isLowerInExpansionZone, upperZoneEnteredAt / lowerZoneEnteredAt, and upperExpectedExpansionAt / lowerExpectedExpansionAt. Each side’s band now expands independently on the 0.5× → 1× → 2× → 4× ladder.Rejection reason consolidated. ORDER_WILL_TAKE_LIQUIDITY_DURING_MARKET_HALT and PRICE_WILL_EXCEED_MAXIMUM_OUTSIDE_RTH_TRADING_BOUND are deprecated (no longer emitted) and replaced by a single FILL_WILL_EXCEED_TRADING_BOUND, covering crossing takers, crossing modifyOrder cancel-replaces, triggered TPSLs, and placements that would rest reachable beyond the band.New features
Maximum order size enforced.POST /v1/placeOrder, POST /v1/modifyOrder, and the batch variants now reject an order whose quantity exceeds the market’s maxOrderSize (see GET /v1/markets) with OrderSizeTooLarge. Reduce-only orders are not exempt.Market-attribute events over WebSocket. The exchangeAttributeUpdates channel now emits marketAttributes entries carrying per-market Regular Trading Hours and off-hours band events: RTH boundary crossings (isOutsideRth), VWAP settlement seals (sealedVwapSettlementPrice), and expansion-zone / band-expansion events (boundEvent: expansionZoneEntered, expansionZoneExited, tradingBoundExpanded).Updates
Candle prices are oracle-derived.GET /v1/candles open / high / low / close are derived from the market’s oracle price feed, not executed trades. volume, takerBuyVolume, the notional volumes, and tradeCount remain trade-derived statistics for the bucket.testnet-v1.1.98
Breaking changes
reduceOnly no longer requires IOC or FOK. POST /v1/placeOrder and POST /v1/modifyOrder now accept reduceOnly: true with any timeInForce — the previous constraint forcing reduce-only orders to be IOC or FOK is removed. Reduce-only position semantics are enforced regardless of TIF, so a resting reduce-only order is now valid.New features
Rolling fees-paid on account stats.GET /v1/account/stats adds rollingFeesPaid — perps trading fees paid over the 14-day fee-tier rolling window (quote quantums, 1e9 = $1), the same window as rollingVolume. It’s computed from an hourly rollup, so it can trail live fills by up to the current partial hour, and reads 0 if that rollup is temporarily unavailable.Mainnet
New features
Lightweight referral-code lookup. NewGET /v1/affiliate/code returns just { address, code, isAffiliate } from a single point read — none of the volume, commission, or fee-tier enrichment that GET /v1/affiliate/info performs. It’s meant for UI surfaces that only need the code (an “Invite Friends” / copy-referral-link control) and may poll every session. Public — no X-API-Key, no signature. “Not an affiliate” is a valid empty state served as 200 with code: "" and isAffiliate: false, never a 404, so callers don’t have to overload the status code. Initially mainnet-only; available on both environments since mid-July 2026.testnet-v1.1.98
Breaking changes
Marketcategory values are now upper-case and add CRYPTO. The category field on GET /v1/api-meta/overview and GET /v1/api-meta/spot/overview now returns EQUITIES, COMMODITIES, INDICES, or CRYPTO, replacing the previous lower-case stocks / commodities / indices. Still omitted for underlyings outside the classified universe.New features
Per-subaccount rate-limit snapshot on write responses.POST /v1/placeOrder, POST /v1/batchPlaceOrders, POST /v1/cancelOrder, POST /v1/batchCancelOrders, POST /v1/cancelAllOrders, and POST /v1/modifyOrder now return a rateLimit object (pool — order or cancel — and remaining tokens after the request) on both REST and WebSocket, so clients can track their remaining budget without an extra call. remaining can be 0 or negative while the request still succeeds when the account is on the drip throttle; -1 is a sentinel meaning the per-subaccount layer was not enforced for this request.clientId echo on rate-limit rejections. The 429 body now echoes the request’s clientId (single-order endpoints) or clientIds (batch endpoints, positionally aligned with the submitted array), so a client firing concurrent requests can correlate the rejection to a specific order or batch.New modify rejection reason. MODIFY_WOULD_CROSS_OUTSIDE_RTH_TRADING_BOUNDARY — a non-crossing modifyOrder reprice rejected because the new price violates the active off-hours trading band. Unlike PRICE_WILL_EXCEED_MAXIMUM_OUTSIDE_RTH_TRADING_BOUND (the crossing cancel-replace path, which removes the original), the original order stays resting on the book unchanged.Rejected setLeverage is now observable on WebSocket. The accountAttributes channel adds a streaming-only leverageReject entry — the REJECTED half of the setLeverage lifecycle. It carries the rejectReason (UNDERCOLLATERALIZED, INVALID_LEVERAGE, or UNKNOWN_MARKET) and the originating requestId for correlation; an applied change still arrives as a leverage entry.Updates
Deterministic market ordering documented.GET /v1/markets now documents that markets are returned sorted by ascending marketId, and the mids map on GET /v1/mids is ordered by ascending marketId and includes only ONLINE markets (OFFLINE markets are omitted).Spot candles stream at every resolution. The api-meta candles WebSocket channel aggregates each resolution (1m through 1w) and a subscription selects one via the SYMBOL/TIMEFRAME id (e.g. AAPL/5m) — previously only 1m was documented.testnet-v1.1.96
Breaking changes
Position-tiered margin fields removed.GET /v1/api-meta/markets and the markets WebSocket channel no longer return transferMarginFraction, incrementalInitialMarginFraction, incrementalPositionSize, baselinePositionSize, or maxPositionSize. Initial margin is no longer scaled by position-size brackets in the published market schema; initialMarginFraction, maintenanceMarginFraction, and the off-hours variants remain.minOrderSize and maxOrderSize removed. The same market reads drop minOrderSize and maxOrderSize, and minOrderSize is no longer a required field. Per-market order sizing is now expressed through minOrderNotional (the $5 minimum-notional floor introduced in testnet-v1.1.93) and stepSize.testnet-v1.1.93
Breaking changes
All-traders leaderboard replaces the affiliate volume leaderboard.GET /v1/affiliate/volumeleaderboard (getVolumeLeaderboard) is gone, replaced by GET /v1/leaderboard (getTraderLeaderboard). A new sortBy query param (volume, pnl, or fees; default volume) chooses the ranking column, and every row now carries volume, feesPaid, and pnl (realized only) together, computed in one query so the three columns are always mutually consistent. The window (all/30d/24h, default 30d) and limit (max 100, no cursor) semantics are unchanged.Notification timestamps are now decimal strings. On GET /v1/api-meta/notifications, createdAtNs is now a string — the value exceeds 2^53 and a JSON number would lose precision in JS clients. Pass it back verbatim as the before_ns cursor (also now a decimal-string query param) and inside ids[].created_at_ns on :markSeen; a truncated value targets the wrong row. :markSeen still accepts a bare number for backward compatibility.Minimum order notional enforced. POST /v1/placeOrder and POST /v1/batchPlaceOrders now reject position-opening orders whose notional (quantity × price) is below $5 with InvalidRequest. Reduce-only orders (including TPSLs) are exempt. The per-market floor is published as minOrderNotional on GET /v1/api-meta/markets.API key keyName removed. POST /v1/createApiKey no longer accepts or returns the optional keyName label.New features
Deposit & withdrawal notifications. The notification inbox now surfacesdeposit and withdrawal events through a new NotificationTransferPayload (subaccountIdx, amount, netQuoteBalance, operationId). These events are not market-scoped, so the enclosing marketId is 0.Off-hours trading-band fields. GET /v1/api-meta/markets and the markets WebSocket channel now expose currentSettlementPrice, currentTradingBound, and nextTradingBound for equity-class markets while outside regular trading hours (omitted in-RTH and for 24/7 crypto markets).Lifetime volume & fees on the fee-tier read. GET /v1/feetiers now returns lifetimeVolume and lifetimeFeesPaid alongside the existing 14-day rollingVolume.Updates
Open interest is now populated.openInterest on GET /v1/api-meta/markets and the markets WebSocket channel now reports the total size of open long positions (equal to total short, in base-asset units), refreshed from a periodic snapshot, instead of the previous placeholder "0".Market category on overview reads. GET /v1/api-meta/overview and GET /v1/api-meta/spot/overview add a category field (stocks, commodities, or indices) for classified equity-class underlyings.Mainnet live
New features
Mainnet is live. The production API is now serving athttps://api.arcus.xyz (REST) and wss://api.arcus.xyz/v1/ws (WebSocket), selectable from the server dropdown on every endpoint page. Testnet (api.testnet.arcus.xyz) remains available, and the two environments share identical paths, payloads, and signing — only the host differs. The code samples and API playground throughout the docs continue to target testnet. See the API introduction.testnet-v1.1.91
Updates
Minimum withdrawal size enforced.POST /v1/withdraw now rejects amounts below the collateral currency’s minimum with 400 — e.g. validation error on field 'amount': must be at least 1000000000 quote quantums (1e9 quote quantums = $1). Amounts must also be exactly representable in collateral base units.compliance address section now conditional. GET /v1/compliance returns the address screening section only when the ?address= query param is supplied; geo is always present. address is no longer a required response field.Spot price & candle WebSocket payloads documented. The api-meta prices and candles WebSocket channels now have published payload schemas (SpotPrices / SpotPrice and SpotCandlesSubscribed / SpotCandlesChannelData) covering both the subscribe snapshot and the per-tick channel_data frames.testnet-v1.1.90
Breaking changes
Order time-in-force rules tightened. New per-order-typetimeInForce constraints, enforced at request validation:- Every order must include
goodTilTime(epoch microseconds) set at least one month in the future — now required even forIOCorders, which previously ignored it. A missing value is rejected withvalidation error on field 'goodTilTime': is required. MARKETorders must useIOC.GTT,FOK, andALOare rejected withvalidation error on field 'timeInForce': must be IOC for MARKET orders.- TPSL orders:
LIMITTPSL legs must useGTT;MARKETTPSL legs must useIOC. (TPSL legs must also bereduceOnly, and are placed viabatchPlaceOrdersgroupings.)
testnet-v1.1.89
New features
Server time.GET /v1/time returns the current server time — useful for aligning the nanosecond signing timestamp with the gateway’s ±30s drift window.testnet-v1.1.82
Breaking changes
Order signing moved to the ordersign typed canonical payload.placeOrder, cancelOrder, and modifyOrder — and each element of batchPlaceOrders / batchCancelOrders — now sign a compact, key-sorted JSON payload built from the parsed request: the payload object is the Ed25519 message, with no timestamp + action prefix. The timestamp is carried as the ct field (it must equal X-Timestamp), and price/size are signed as integer ticks/quantums derived from the market’s tickSize / stepSize. The previous X-Timestamp + action + canonicalJSON(body) scheme is now rejected with 401 for these endpoints. cancelAllOrders, setLeverage, and WebSocket authentication keep the legacy message. See Authentication.GTC replaced by GTT. The timeInForce enum is now GTT, IOC, FOK, ALO. Resting orders (GTT, ALO) require goodTilTime (epoch microseconds) set at least one month in the future at the time the order is processed; nearer or missing values are rejected.Withdrawals now use EIP-712 typed data. POST /v1/withdraw authenticates with an eth_signTypedData_v4 signature over a Withdraw typed payload (domain and types in the endpoint reference) instead of the previous SHA-256 ECDSA canonical message.Market orders require a protective price bound. A MARKET order’s price must be within 10% of the current mark price (TPSL market orders: within 10% of the trigger price), or the order is rejected. With this bound, market orders behave like marketable limit orders.Updates
New order rejection reason.PRICE_WILL_EXCEED_MAXIMUM_OUTSIDE_RTH_TRADING_BOUND is added to the RejectionReason set delivered on the orders WebSocket channel — emitted when a resting order’s price would breach the maximum off-hours trading bound once the current regular-trading-hours session ends.Endpoint migration
Breaking changes
API base URLs moved toapi.testnet.arcus.xyz. REST is now https://api.testnet.arcus.xyz and WebSocket wss://api.testnet.arcus.xyz/v1/ws/. The previous hostnames are being retired — update any saved base URLs, SDK configs, and clients at your earliest convenience to avoid disruption. Paths and payloads are unchanged. See the API introduction.testnet-v1.1.79
New features
Spot market overview REST endpoint.GET /v1/api-meta/spot/overview returns the curated spot market universe in source order, with each entry augmented by Market Cap and logo_url from the latest stored market metadata profile when available. Public — no X-API-Key or signature required.testnet-v1.1.78
Breaking changes
Candles pagination replaced.GET /v1/candles no longer accepts limit. A request must now pass to — the upper bound of the window as a Unix microsecond timestamp (seconds- or milliseconds-scale values are rejected) — and may scope the lower bound with either countback (number of closed bars counting back from to) or from (a microsecond lower bound); from and countback are mutually exclusive. A request without to now returns 400.volume30d renamed to rollingVolume. GET /v1/account/stats and the affiliate commission and claim schemas now report notional fill volume under rollingVolume, measured over the fee-tier rolling window rather than a fixed trailing 30 days. Update any client that reads volume30d.Updates
New order rejection reasons. TheRejectionReason set delivered on the orders WebSocket channel adds OPEN_ORDER_CAP_EXCEEDED, ORDER_NOT_FOUND, ORDER_NOT_FOUND_FOR_MODIFY, MODIFY_CHANGED_IMMUTABLE_FIELD, MODIFY_ZERO_SIZE, and ORDER_WILL_TAKE_LIQUIDITY_DURING_MARKET_HALT.Market asset name in metadata. Market metadata responses now include fullAssetName (e.g. Bitcoin) when a canonical name is configured for the market.testnet-v1.1.75
Breaking changes
Unified request signing. REST and WebSocket now share one signing message:X-Timestamp + action + canonicalJSON(body), where action is the canonical operation name — the REST path’s final segment or the WebSocket request type (e.g. placeOrder, cancelOrder). The HTTP method and the /ws/v1/ path prefix are no longer part of the signed message; re-sign with the new message before sending or the request is rejected with 401 invalid signature. Batch methods sign each element over its singular action (e.g. placeOrder for each order in batchPlaceOrders) with one shared timestamp. The cutover also invalidates API keys registered before it — re-register via POST /v1/createApiKey (EIP-191 registration is unchanged). See Authentication.testnet-v1.1.74
Breaking changes
Protected requests now require nanosecond timestamps. The signing timestamp —X-Timestamp for REST, timestamp for WebSocket order methods — must now be Unix time in nanoseconds as a decimal string (e.g. 1713825891591000000), not milliseconds. Millisecond or second epochs are rejected with 401 Unauthorized. Update any client that builds the signing message before re-signing. See Authentication.Updates
User-facing timestamps are now microseconds. Response time fields — candleopenTime, funding payment times, and order placement/update times — are emitted in Unix microseconds for consistent precision across the API.testnet-v1.1.70
New features
Market overview REST endpoint.GET /v1/api-meta/overview returns a consolidated per-market overview keyed by base asset, so clients can fetch headline market data in a single call.Volume leaderboard REST endpoint. GET /v1/affiliate/volumeleaderboard returns the top addresses ranked by signed-notional fill volume over a rolling window — all, 30d, or 24h (default 30d).Referral commission rate schedule. GET /v1/commissionrates returns the referral commission rate schedule used to compute affiliate payouts on each fill.testnet-v1.1.69
New features
Push notification device tokens. Register an Expo push token for the calling wallet withPOST /v1/api-meta/notifications/tokens so the notifications consumer can deliver a push when a matching event (resting fill, liquidation, TP/SL trigger) lands, and remove it with DELETE /v1/api-meta/notifications/tokens.testnet-v1.1.65
New features
Rate-limit usage REST endpoint.GET /v1/rateLimit returns the state of both per-subaccount throttle pools (order and cancel), so clients can self-pace and see which limit is currently constraining them.Withdrawals REST endpoint. POST /v1/withdraw submits a withdrawal of collateral to the chain.Market metadata REST endpoints. GET /v1/api-meta/markets returns curated reference data — company profile, branding, headline financials, and TradingView chart identifiers — for one or all markets. Branding icons and market capitalizations are served by GET /v1/api-meta/overview, which folds in what were briefly separate icons / marketCaps projections.Notifications REST endpoints. List the most recent notifications for an address (newest-first) with GET /v1/api-meta/notifications, and mark them read with PATCH /v1/api-meta/notifications:markSeen — either an explicit list of (created_at_ns, notification_id) pairs, or the most recent limit rows for the wallet via all=true.Referral code availability. GET /v1/affiliate/codeAvailable returns { code, available } for a single referral code string.testnet-v1.1.56
New features
Fee tier table REST endpoint.GET /v1/feetiers returns the full fee tier table, sorted ascending by level (0=Base through 4=Platinum) — the maker/taker fee BPS for each tier and the 30-day notional volume threshold required to reach it.Exchange attribute updates WebSocket channel. Subscribe to exchangeAttributeUpdates for exchange-wide state, discriminated by entry type. The current type, feeTierConfig, sends the full fee tier table on subscribe and a fresh replacement whenever an operator updates it — the streaming counterpart to GET /v1/feetiers.testnet-v1.1.54
New features
Account attribute updates WebSocket channel. Subscribe toaccountAttributeUpdates for live per-account state — effective leverage per market and the account’s current trading fee tier — discriminated by entry type ("leverage" or "feeTier"). On subscribe the server sends one leverage entry per market plus, when available, one fee tier entry; updates stream a single-entry delta for whichever attribute changed.Leverages REST endpoint. GET /v1/leverages returns the effective leverage for (address, accountIndex) across every market, sorted by ascending marketId. Each entry reflects the user’s override (set via POST /v1/setLeverage) when one exists, otherwise the market default.Account stats REST endpoint. GET /v1/account/stats returns 30-day rolling notional fill volume and the current trading fee tier (level + BPS) for any Ethereum address.Updates
Affiliate endpoints moved. All/v1/api/affiliate/* paths are now under /v1/affiliate/* — the legacy /api/ segment has been dropped. Update any clients that hard-coded the old prefix. Operation IDs and request/response schemas are unchanged.testnet-v1.1.47
New features
Trades REST endpoints. Query recent public trades for a market withGET /v1/trades, or fetch a single trade by ID with GET /v1/trade/{tradeId}.Funding payments — REST and WebSocket. Track per-account funding history with GET /v1/funding and per-market rates with GET /v1/fundingRates. Stream live funding payments over the new funding WebSocket channel — snapshot of the 100 most recent payments on subscribe, then one event per (market, account) at each funding time. Positive payment = received, negative = paid.Portfolio history. GET /v1/portfolio returns account equity, PnL, and value-over-time history for charting.Positions REST endpoint. GET /v1/positions returns the current open positions for an account — the REST counterpart to the existing positions WebSocket channel.Cancel-all and set-leverage. POST /v1/cancelAllOrders cancels every open order for an account in one call; POST /v1/setLeverage updates per-market leverage.Account transfer updates. GET /v1/accountTransferUpdates returns deposit/withdrawal history with cursor pagination.User preferences. Persist client-side UI settings server-side via /v1/api-meta/userPreferences.Referral program. Twelve new endpoints under /v1/api/affiliate/* cover the full affiliate lifecycle — create and revoke referral codes, register affiliates, view referees and leaderboard, track commissions and kickbacks, and claim rewards.Initial testnet release
New features
REST and WebSocket API now live on testnet. Trade, stream market data, and manage accounts againsthttps://api.testnet.arcus.xyz (REST) and wss://api.testnet.arcus.xyz/v1/ws/ (WebSocket). Both APIs are non-custodial — register an Ed25519 API key against your Ethereum address and the server never sees a private key. See the API introduction to get started.Real-time market data channels. Subscribe to live updates over WebSocket:l2Orderbookandl2OrderbookUpdates— full snapshots every ~500 ms, or initial snapshot plus incremental updates (1–100 levels).bbo— best bid and offer at the top of book.trades— live public trade stream.markets— global market metadata with funding rate, oracle and index prices, and 24h volume.oraclePrices— per-market oracle prices from the on-chain Slinky aggregator.candles— OHLCV across 13 timeframes from1mto1w, with up to 200-candle snapshots.
account, positions, orders, and userFills.Order routing over WebSocket. Place, cancel, modify, and batch orders directly over WebSocket. All order methods are asynchronous and return a 202 ACK — observe lifecycle through the orders and userFills channels. See Placing orders.Ed25519 API keys with Ethereum-signed registration. Generate an Ed25519 key pair, register it with an ECDSA signature from your master Ethereum address, and sign protected requests with a Unix-millisecond timestamp. Full instructions in Authentication.Updates
Rebranded to Arcus. The product is now Arcus across all user-facing surfaces, including the API spec and documentation.Known limitations
batchModifyOrdersis not yet implemented and returns501.createApiKeyis REST-only; the WebSocket equivalent returns501 NotImplemented.