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Offerbook is a peer-to-peer lending protocol on Solana. Users borrow or lend USDC against onchain collateral (the asset locked by the borrower for the duration of the loan). Loan duration is set by the offer creator (1 to 30 days), with no price-based liquidations and no oracles. This FAQ covers the most common questions.

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Assets

Any Solana asset (verified tokens on Jupiter, RWAs such as xStocks, NFTs from whitelisted collections) can be used as collateral. The collateral you choose directly affects how attractive your offer is.
USDC (a dollar-pegged stablecoin) is the only asset that can be borrowed or lent on Offerbook.

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Offers

Both borrowers and lenders can create offers through a step-by-step flow: choose a side (borrow or lend), define the collateral asset and amount, USDC amount, LTV (Loan-to-Value, the ratio between borrowed USDC and collateral value), APR (Annual Percentage Rate, for borrowers) or APY (Annual Percentage Yield, for lenders), loan duration, expiration, and partial fill preferences. The offer is then published in the offerbook.Lenders: Make sure your escrow wallet has sufficient USDC before publishing. Offers without enough balance will not be visible to other users.
No. To change the terms of an offer, you need to remove it and create a new one. However, once an offer expires, you can renew it directly without recreating it (with the option to adjust the LTV before renewing).
Yes. An offer can be removed at any time before it is accepted. No fees are charged.
Lend offers expire after 24 hours (fixed). Borrow offers expire after 1, 3, or 7 days (set by the borrower at creation).This is separate from the loan duration: the loan countdown only starts when an offer is accepted, not when it is published.
It depends on the offer creator’s settings. When creating an offer, the creator can enable or disable partial fill, and set a Minimum Fill Amount (in USD). If partial fill is enabled, you can accept any amount equal to or greater than the Minimum Fill Amount. If disabled, the offer can only be filled in full.Partial fill is not available for offers using NFT collateral.
There is no fixed minimum or maximum at the protocol level. The Minimum Fill Amount can be set per offer when partial fill is enabled.
No. Users can have multiple offers active at the same time.
A counter offer is a proposal to modify the terms of an existing open offer before accepting it. Any user can send a counter offer on any open offer, adjusting one or more of: LTV (Loan-to-Value, the ratio between borrowed USDC and collateral value), APR (Annual Percentage Rate), and amount.The original offer creator can review counter offers received and accept one (starting the loan at the counter-offer terms) or ignore them. The original offer remains open while counter offers are pending. Counter offers do not lock any funds until accepted. See Counter Offers for details.
Yes. NFTs from whitelisted collections can be used as collateral. Lend offers using NFT collateral are collection-bid offers: the lender does not target a specific NFT; any borrower can pledge any qualifying NFT from the supported collection.Partial fill is not available for NFT collateral, since an NFT cannot be partially transferred. For NFT collateral with a known floor price, the LTV slider uses the floor price as the reference collateral value.

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Loans

A loan starts when an offer is accepted. Once matched, the collateral is locked onchain via a smart contract (a PDA, or Program Derived Address, which is a program-owned account on Solana with no private key) and the USDC is transferred. All loan terms are fixed and immutable from that point. The loan duration begins at this moment.
Loan duration is set by the offer creator (borrower or lender) and can range from 1 to 30 days. Common presets are 3D, 7D, and 30D. The countdown starts when the offer is accepted, not when it is published. Once the loan starts, the duration cannot be changed.
Offer expiration is how long the offer stays visible in the offerbook (24 hours for lend offers, 1 to 7 days for borrow offers). Loan duration is how long the loan lasts once the offer is accepted (1 to 30 days). These are two separate timers.
Yes. Borrowers can repay the loan at any time before maturity. The full interest for the agreed loan duration is owed regardless of when the repayment occurs. There is no partial interest or fee reduction for early repayment.
After the loan duration ends, the lender can claim the collateral by signing a transaction. This action triggers the collateral transfer: the collateral is sent directly to the lender (not sold on the market). A 0.1% fee is deducted from the collateral at transfer (no fee on NFT/RWA).The collateral transfer is not automatic. It only happens when the lender claims. The borrower can still repay and recover the collateral at any time, as long as the lender has not claimed it.
Do not rely on this window. The lender can claim at any moment after maturity. Always plan to repay before the loan expires.
No price-based liquidation, margin call, or forced closure can occur during the loan. However, the collateral is still exposed to price fluctuations. If its value changes significantly, this affects the outcome at maturity for both sides.
A loan can have one of three statuses:
  • Active: the loan is running, between offer acceptance and maturity.
  • Repaid: the borrower has repaid the loan, the collateral has been returned to their wallet.
  • Defaulted: the loan has reached maturity without being repaid. The lender can claim the collateral.
The collateral is locked onchain via a smart contract (a PDA, or Program Derived Address, which is a program-owned account on Solana with no private key) for the full duration of the loan. Neither the borrower nor the lender can access it during this period.
The borrower pays the principal plus the full interest for the loan duration. The collateral is returned directly to the borrower’s wallet. The lender receives the USDC (principal + interest, minus the 10% repayment fee) in their escrow wallet.
For tokens where yield accrues in the token value itself (such as liquid staking tokens), the collateral value will grow during the loan. For tokens where yield must be actively claimed, the yield may not be accessible while the collateral is locked.

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Fees

Offerbook applies fees at three stages:
  1. At loan start: 25% of the estimated total interest is taken immediately (USDC), paid by the borrower.
  2. At repayment: 10% of the interest is deducted from the lender’s return.
  3. At collateral transfer: If the borrower does not repay and the lender claims the collateral, 0.1% is deducted from the collateral (no fee on NFT/RWA).
The borrower pays the fee at loan start (25% of estimated interest). The lender pays the fee at repayment (10% deducted from interest received) and at collateral transfer (0.1% deducted from collateral received).
The Effective APR (borrower) and Effective APY (lender) account for platform fees and are displayed in the offer summary.
  • Effective APR is higher than the offer APR because the 25% upfront fee is added on top of the interest. Example: an offer at 30% APR becomes 37.5% Effective APR (30% × 1.25).
  • Effective APY is lower than the offer APY because the 10% fee is deducted from the interest received. Example: an offer at 5% APY becomes 4.5% Effective APY (5% × 0.9).
If a lender fills a borrow offer, the borrower receives the USDC amount minus the fee. If a borrower fills a lend offer, the borrower pays the fee right after receiving the USDC.
No. The full interest for the agreed loan duration is always owed, regardless of when the repayment occurs.
Yes, two other types. Offerbook has three cost types in total:
  1. Network fees — Solana gas, around 0.000005 SOL per signature. Never refunded.
  2. Account rent — a refundable deposit Solana requires for each new account. Most of it comes back when the account is closed.
  3. Protocol fees — Offerbook’s cut in USDC (see the fee questions above). Never refunded.
Account rent by account type:
  • User account: 0.00233856 SOL — first time you use Offerbook. Not refundable.
  • Escrow account (per asset): 0.00203928 SOL — first deposit of a given asset. Not refundable for the moment.
  • Offer account: 0.00940992 SOL — each offer created. Refunded when the offer is filled, cancelled, or expires.
  • Loan account: 0.00651456 SOL — when a loan opens. Not refundable for the moment.
  • Loan vault: 0.00203928 SOL — when a loan opens. Refunded when the loan is repaid or the collateral is claimed.
Rule of thumb: fees are gone, rent is a deposit (some of it is returned when the account is closed). See Fees & Costs → Account Rent for more.
Offerbook offers a referral system that applies at every stage where a fee is charged. By default, each fee is split:
  • Referred user: 20% of the fee
  • Referrer: 30% of the fee
  • Protocol: 50% of the fee
The referred user benefit goes to the side paying or receiving at that stage: the borrower at loan start, the lender at repayment and collateral transfer.If both sides of the loan were referred, the 30% referrer share is split equally between the two referrers.
Yes. Fees are set in the onchain configuration and can be updated by protocol admins. The rates described above are the current defaults.

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Risks

If you do not repay before the end of the loan duration, the lender can claim your entire collateral at any moment. While you can technically still repay until the lender claims, do not rely on this window. Repayment timing is your responsibility. The full interest is always owed, even if you repay early.
Collateral value is not monitored during the loan. If the collateral loses significant value before maturity and the borrower does not repay, you receive the collateral token directly (not USDC), and may need to sell it at a loss. The higher the LTV (Loan-to-Value, the ratio between borrowed USDC and collateral value), the higher this risk. You must also manually claim the collateral after maturity.
No price-based liquidation, margin call, or forced closure can occur during the loan. However, the collateral is still exposed to price fluctuations. If its value changes significantly, this affects the outcome at maturity for both sides.
No. Offerbook loans are time-based. Market price movements during the loan do not trigger any liquidation or margin call. After maturity, if the borrower has not repaid, the lender can claim the collateral by signing a transaction. This is a direct transfer, not a sale on the market.
Yes. Offerbook has been audited by Cantina. The full report is available here: Cantina Audit (May 21, 2026).

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Escrow Wallet

A dedicated wallet, separate from your main Solana wallet, used to hold funds while interacting with Offerbook. Each user has one escrow wallet. All funds transit through the escrow when creating or accepting offers.For lenders, the escrow is visible in the interface. For borrowers, it is used in the background and is not visible.
Yes. Lenders need to deposit USDC manually before creating offers. You can create offers without sufficient balance, but they will not be visible to other users until the balance covers them.
Yes. Lenders can create multiple lend offers from the same USDC balance, and all of them are visible at the same time. When one offer is accepted and the USDC leaves the escrow, any remaining offers that are no longer covered by the balance are hidden automatically.
Yes. You can withdraw USDC at any time. If withdrawing makes your balance insufficient to cover active offers, those offers are automatically hidden.
When a borrower repays a loan, the USDC (principal + interest, minus the 10% fee) returns to the lender’s escrow. It can be reused for new offers without withdrawing to your wallet first.
For borrowers, the escrow is invisible. Collateral transits through the escrow automatically in a single transaction when creating or accepting an offer. When the borrower repays, collateral is returned directly to their wallet.
Depositing an asset into your escrow requires funding a Solana account: 0.00203928 SOL the first time you deposit a given asset. This rent is a deposit rather than a fee, but it is not refundable for the moment.A separate escrow account is required for each distinct asset, so borrowers typically open more of them over time than lenders, who generally only need a USDC account.The first time you ever use Offerbook, a one-time user account rent of 0.00233856 SOL also applies (not refundable). See Fees & Costs → Account Rent for the full breakdown.

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Notifications & Settings

Open the Settings page (gear icon in the navigation header), then go to the General tab and connect a notification channel: Telegram or Email. Connecting a channel requires signing a message to prove you own the wallet.Once at least one channel is connected, the Notifications tab becomes active. You can then toggle individual notification types on or off (Offer accepted, Counter offer received, Loan due soon, etc.). See Settings & Notifications for the full list.
Hardware wallets (Ledger and others) cannot sign arbitrary messages. To connect a notification channel with a hardware wallet, enable I’m using a hardware wallet in the General settings. Authentication then uses a signed transaction instead of a signed message.
Auto top-up is an Escrow Setting that automatically deposits the required funds from your main wallet into your escrow when you create an offer. Two independent toggles are available:
  • Top up on Create Borrow Offer: deposits collateral into escrow when creating a borrow offer.
  • Top up on Create Lend Offer: deposits USDC into escrow when creating a lend offer.
Both are configured per user in Settings. When disabled, you need to deposit funds manually into your escrow before publishing.
Pro Mode is a planned toggle to unlock advanced options and controls across the interface. It is not currently available.

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Chat

Click the floating green button in the bottom-right corner of the interface and choose Messages. The first time you open Chat, approve the wallet signature to authenticate. You can then join public Channels (currently just General) or send a Direct message to another user by username or wallet address. See Chat for the full overview.
Hardware wallets cannot sign arbitrary messages. When you click Connect to chat with a Ledger, the app detects the failure and offers to switch to a memo transaction signature instead. Approve the empty memo transaction in your wallet to complete sign-in. Your wallet needs a small SOL balance to pay the network fee.
From any conversation (channel or DM), click the + button on the left of the message input and choose Send an offer. A list of your open offers appears; select the one you want to share. The recipient sees a preview card with the offer terms (principal, collateral, APY, duration, LTV) and can open the full offer with one click.