Arcus

Arcus is a non-custodial perpetuals DEX built by the dYdX Labs team together with Robinhood Crypto, running on Robinhood Chain (an Arbitrum-based EVM L2). It pairs crypto perps with stock perps (TSLA, NVDA, SPY, GOOGL, …), and CubeTerminal trades it the same way it trades Hyperliquid: one setup step, then every order signs locally with zero popups.

⚠️

Arcus is integrated but not yet live in CubeTerminal. The venue ships dormant — it shows a "Soon" badge in the exchange list and is not selectable — until Arcus opens its perps publicly. This page documents how the integration works so it's ready the moment the venue flips on. Once enabled it runs against Arcus testnet by default (perps are closed-beta on mainnet); the connection flow, signing and UI are identical — only the host flips when mainnet opens.

Why Arcus is different

Stock perps next to crypto — trade TSLA, NVDA or SPY perps in the same book style as BTC and ETH.
Self-custody — collateral sits in your own Arcus account on Robinhood Chain; the exchange never holds your keys.
No per-order approvals — authentication is an Ed25519 trading key registered once with a single wallet signature. Orders sign locally and are gasless.
Limited-permission key — the trading key can place, cancel and modify orders. Withdrawals require a separate wallet-level signature; the trading key alone cannot move funds off the exchange.

Connecting

Open Settings → Trading Accounts → Arcus. There are two ways in — both end in popup-free trading.

Option A — MetaMask / Rabby (one signature, once)

Use this if your Arcus funds live under a browser-extension wallet.

Choose a password — it encrypts the trading key on your device
Click Connect MetaMask / Rabby
Your wallet prompts to connect, then to sign one personal_sign message — this registers the freshly generated trading key under your address
Done. Every order from now on signs locally — no popups

The trading key is generated locally, stored AES-encrypted in the terminal keystore, and never leaves the device. The registration is valid for 180 days, after which you re-approve with one more signature.

Option B — Terminal wallet (zero popups, including setup)

Use this if you want everything inside the terminal.

Create or unlock an EVM terminal wallet in the On-Chain Wallets section below the Arcus card
Return to the Arcus card and click Connect Arcus

That's it — no extension, no popup at all. The trading key is derived from the terminal wallet, so nothing extra is stored: unlocking the wallet is enough to restore the session on any reload.

Both paths register the trading key with a single EIP-191 signature from the wallet that owns the Arcus account. The wallet's private key itself is never sent anywhere.

Trading

Order types — market and limit, with post-only (ALO), IOC and FOK time-in-force; reduce-only supported.
Modify in place — resting orders can be re-priced/resized without cancel + re-place.
Leverage — set per market from the Trade Entry widget (max leverage varies per market).
Engines — Chase, Scale and TWAP all route through Arcus like any other venue.
Symbols — markets are USD-quoted (BTC, TSLA); stock perps carry an STK badge in the Symbols widget.

⚠️

Take-profit / stop-loss orders are not available on Arcus yet — the venue hasn't shipped TPSL placement, so the terminal doesn't wire it up. It will enable them the moment Arcus ships the feature.

Deposits & withdrawals

The Arcus card in Settings includes a Deposit / Withdraw row.

Withdrawals (testnet and mainnet)

Withdrawals are signed with an EIP-712 message — silent for terminal wallets, one popup for MetaMask/Rabby. Funds arrive at your own address on Robinhood Chain automatically; there is no claim step. Minimum $1.

Deposits

Testnet — the terminal mints test USDG, approves the deposit proxy and submits the deposit in one flow, signed silently by your terminal wallet. You need a small amount of Robinhood-testnet ETH for gas.
Mainnet — deposits run through Arcus's own funding flow at app.arcus.xyz (opens in a new tab) (cards, exchange transfers, cross-chain bridging). The terminal links you there.

Spot stock tokens

Arcus also lists spot stock tokens (real ERC-20s on Robinhood Chain). In CubeTerminal:

The Symbols widget shows a Spot stock tokens section with live prices and 24h change while Arcus is the active exchange.
Spot trading itself happens in the Arcus app — Arcus has not published a public spot-trading API yet (spot trades are wallet-signed per trade in their interface). Open app.arcus.xyz (opens in a new tab) to trade spot; your holdings are plain ERC-20s in your own wallet.

Supporting CubeTerminal

After connecting you'll see an optional Support CubeTerminal card. It binds your Arcus account to the terminal's referral code (MRCUBE) — a share of the trading fees you'd pay anyway goes to CubeTerminal, at no extra cost to you. Per Arcus's rules the binding is one-time and permanent (one referrer per account), which is why it's opt-in and clearly labeled.

Sub-accounts

One Arcus address holds up to ten account indexes (0–9). CubeTerminal registers the trading key against index 0 by default; additional indexes will surface in the Accounts widget as Arcus's sub-account tooling matures.

Known limits

TPSL — waiting on Arcus (see above).
Testnet gas — the deposit flow needs Robinhood-testnet ETH, which currently has no public faucet; the Arcus testnet web app can credit test funds directly.
Mainnet perps — closed beta; the terminal flips to mainnet when access opens.

Phoenix Terminal Wallets