Using Fyber from the Robinhood Wallet
The protocol lives on Robinhood Chain and is designed for a phone. What you need, what you do not need, and what depends on a third party.
Fyber runs on Robinhood Chain, chain ID 4663. The stock tokens exist there and, as far as their issuer's documentation goes, only there. The reference interface is built mobile-first for the wallet's built-in browser, because that is where the collateral already sits.
What you need
- The Robinhood Wallet, with stock tokens in it, or USDG if you are depositing rather than borrowing.
- Nothing else. No account with anyone, no application, no minimum balance beyond the 100 fyUSD fyUSD minimum debt.
What you do not need
You do not need ETH. The reference interface sponsors transaction fees through account abstraction, so the notion of gas never appears. Arriving with a zero native balance is the expected case.
Risk
Fee sponsorship is a service provided by whoever operates the front end, not by the protocol. It can stop. If it does, the contracts still work — you would then need the chain's native token to pay for transactions yourself, like on any other chain.
Rules R-15 preamble, R-12.6.1
Connecting
The interface connects through the wallet's injected provider inside its dApp browser, or through WalletConnect from a desktop. There is no sign-up, no email, no password and no custody: the protocol never holds anything on your behalf outside a position you opened.
Before your first transaction
Two things happen once, and only once:
An attestation. You confirm you have read the twelve mandatory disclaimers, which are expandable on the same screen and reproduced verbatim in Disclaimers. This is a condition of using the reference interface, not a condition written into the contracts.
Rules R-15.4.1, R-15.4.3
What the interface asks you for
Two numbers to borrow — amount and rate — and a collateral card to pick from. Nothing else. One risk figure is displayed: the price at which you would be liquidated. There is no health factor, no gauge and no score, because a single number that anyone can check against a market price is harder to misread than a composite one.
The amount slider starts at half of your maximum, not at your maximum.
Rules R-15.1.1, R-15.1.2
Approvals
Borrowing needs an ERC-20 approval on the stock token, repaying needs one on fyUSD, and repaying in USDG needs one on USDG. fyUSD supports EIP-2612 permit, so a repayment can be signed rather than approved in a separate transaction where the interface offers it.
Guarantee
The only fyUSD any Fyber contract burns is the caller's own, through the standard ERC-20 allowance. There is no privileged path that lets a module burn a third party's balance, and no mechanism by which a small approval becomes an unlimited one.
Rules P6, R-2.1.3
One address, one position per branch
You can hold a SPY position and a QQQ position at the same time, but not two SPY positions from the same address. If you want two different rates on the same collateral, you need two addresses.
Rule R-5.1.1
The chain itself
Risk
Robinhood Chain is an Arbitrum Nitro rollup whose sequencer is operated by a single party, which can in principle delay, filter or reorder transactions without notice. Whether a sequencer uptime feed exists on this chain is one of the open verification items listed before launch; if none is available, the protocol cannot detect a sequencer outage and that risk is documented rather than mitigated.
Using this chain also means accepting the chain operator's own terms of service, which impose US arbitration, a class-action waiver, Delaware law and a prohibition on VPN use. Those terms cover the sequencer, the public RPC and the trademarks — not Fyber — but they apply to you as a user of the chain.
Rule R-15.4.1 (4)
If the interface disappears
Every function is permissionless and callable directly. Liquidations, redemptions, PSM swaps, the sale of liquidated collateral, branch activation, depth sampling and shutdown are all incentivised or free for anyone to call, and every operation that depends on a maintenance call performs that call itself. The protocol was built to pass a specific test: everything keeps working the day after the team stops existing.
Rules R-1.4.2, R-12.6.1
Last reviewed: 2026-09-07 · Spec v0.4