How your keys are kept safe

Your funds aren't safe because we promise they are. They're safe because the venues won't let us touch them, and because our own systems never hold your credential in one readable piece.

fxyz's security model is built to avoid single points of failure. Two independent fronts protect you, and either one on its own would already be enough.

The biggest promise comes first

fxyz cannot withdraw your funds. Even we cannot. The venues themselves refuse.

This is not a policy we enforce. It is a property of the venues' own protocols. The credential fxyz holds simply cannot withdraw, and that restriction lives in code the venues wrote, not us:

• On Hyperliquid, fxyz holds an "agent key" that the protocol restricts to trading. The HL contract refuses any withdrawal signed by it. Only your main wallet, which fxyz never holds or sees, can move funds.
• On Lighter, the L2 protocol routes every withdrawal back to your registered L1 owner address. There is no field on the wire to redirect it, so funds can only go home to you.
• On Backpack, fxyz's own client contains no withdraw operation, so no code path inside the product can move funds off your account. Backpack's withdrawal-address whitelist adds a venue-side seal on top.

To move your funds, an attacker would have to defeat the venues' protocols themselves, the same infrastructure that holds billions of dollars across the industry. Defeating fxyz alone gets them nothing.

How the credential itself is protected

Your credential is never held as a single readable value anywhere: not in a database, not in a vault, not in memory, not in a backup.

The credentials are trade-only and can't move funds, but we still treat them as if they could.

Reconstructing any single user's credential would require breaching several independent, separately controlled systems at the same time. And the work doesn't scale: defeating the protection for one user gives an attacker nothing toward the next. There is no master list anywhere that maps users to credentials. Every user is a fresh problem, with fresh keys, in fresh systems, under fresh access controls.

What this gives you:

• Per-user cryptographic isolation. There is no single secret that unlocks everyone.
• No single point of compromise. A breach of any one system yields nothing usable on its own.
• Tamper evidence, end to end. Authenticated encryption means any modification along the chain is detected and rejected, never silently accepted.
• An uninformative storage layout. Nothing about how the credential is stored hints at what to look for or where.

Each layer multiplies the work required rather than adding to it, and each system sits under its own access controls with its own monitoring. No engineer can run a script and dump everyone's credentials, because no such ability exists in the system.

Per-user isolation, all the way down

Even running code is partitioned.

When you trade through fxyz, the strategy signing your order runs inside a private workspace scoped to your wallet and nothing else. Other users have their own workspaces. They cannot see your credential, list your files, or place trades on your account. There is no shared all-users process holding credentials in memory, and no privileged path that reaches across.

The blast radius of anything that happens inside a workspace ends at that workspace's wall. Even a deliberately malicious bot, whether written that way by its author or twisted by an attacker, stays scoped to its own user. The infrastructure gives it no other reach.

The strategy itself cannot betray you

The exchange clients exposed to strategy code deliberately omit fund-movement operations. There is no withdraw() and no transfer(). The functions don't exist in the surface available to your code, so a strategy you wrote, or any strategy you forked, has nothing to call.

This guarantee doesn't only live at the venues. It is enforced inside fxyz itself, in code, at the API surface. Both walls have to hold, and both do.

In summary

• fxyz can place trades for you. That's the design. Anything you build, fork, or run that you tell to trade, can trade.
• fxyz can't move your funds. Neither can a malicious bot or a misbehaving strategy. The venues themselves see to that.
• Your credential is split across independent systems, isolated per user, with no master list and no shortcut.

What's next

• Per-exchange custody: how each venue enforces the funds-stay-yours guarantee.
• What fxyz cannot do: the explicit list.