FOIL Documentation
Learn how FOIL enables NFT-backed lending on Solana, allowing collectors to access liquidity without selling their prized trading cards.
Introduction
FOIL is a DeFi lending protocol built on Solana that enables users to borrow against NFT trading cards while allowing lenders to earn yields on loans backed by verified collectible assets.
Our Mission
We believe collectors should never have to choose between holding their prized cards and accessing the capital they need. FOIL bridges this gap by creating a trustless lending market for NFT trading cards.
For Borrowers
Access liquidity without selling your collection. Use your verified trading cards as collateral and get USDC loans up to 70% of the insured value.
For Lenders
Earn yields on loans backed by insured, verified collectible assets. Your capital is protected by real-world valued NFTs held in escrow.
How It Works
The FOIL protocol follows a straightforward loan lifecycle from request to completion.
// Loan Creation Flow
1. Borrower selects NFT from wallet
2. Platform verifies NFT against supported collections
3. Insured value determines max loan (70% LTV)
4. NFT transferred to secure escrow
5. Loan request visible to lendersTechnical Overview
FOIL is built on modern blockchain infrastructure designed for speed, low costs, and robust NFT support.
Why Solana?
Speed
400ms block times enable near-instant transaction confirmations, making the lending experience feel seamless.
Low Cost
Transaction fees are fractions of a cent, making micro-loans economically viable and reducing barriers to entry.
NFT Infrastructure
Native Metaplex standard provides robust metadata handling and creator verification built into the ecosystem.
Architecture
FOIL consists of three main layers working together:
Frontend
Next.js application with TypeScript, providing a responsive interface for managing loans, viewing NFTs, and connecting wallets.
Wallet Integration
Solana Wallet Adapter supporting Phantom, Solflare, Backpack, and other popular wallets for secure transaction signing.
Smart Contract
Anchor Framework program handling escrow, loan management, and position trading with on-chain security guarantees.
NFT Verification
Every NFT submitted as collateral is verified against our registry of supported collections using Metaplex metadata.
// NFT Collection Verification
function verifyNFT(nft_metadata):
for collection in supported_collections:
for creator in nft_metadata.creators:
if creator.address == collection.creator
AND creator.verified:
return { valid: true, collection }
return { valid: false }Only NFTs from verified creators in supported collections can be used as loan collateral, ensuring asset authenticity.
Smart Contract Overview
The FOIL smart contract manages the entire loan lifecycle with on-chain security guarantees.
Account Structures
The protocol uses four primary account types to track state:
Config
Global program configuration including treasury address, fee rates, supported collections, and operational parameters.
LoanRequest
Individual loan proposals with terms (amount, rate, duration), NFT details, insured value, and current status.
ActiveLoan
Funded loans tracking principal, interest accrued, repayment progress, due dates, and escrow details.
LoanPosition
Enables secondary market trading of loan positions, tracking current holder and listing status.
Loan Lifecycle
Loans progress through defined states from creation to completion:
// Loan State Machine
RequestStatus:
Open -> NFT with borrower
EscrowReady -> NFT in escrow, awaiting funding
Funded -> Loan active
Cancelled -> Borrower cancelled
Expired -> Request timed out
LoanStatus:
Active -> Repayment pending
Repaid -> NFT returned to borrower
Defaulted -> NFT claimable by lenderSecurity Features
The protocol implements multiple layers of security to protect users:
Maximum LTV
Loans capped at 70% of insured value for lender protection
Grace Period
Borrowers get 72 hours after due date before NFT can be claimed
Secure Escrow
NFTs held in PDA-controlled escrow until loan completion
Creator Verification
On-chain verification of NFT authenticity via Metaplex metadata
Roadmap
FOIL is currently live on Solana Devnet with mainnet launch planned after security audit completion.
Current Status
The full protocol is deployed and operational on Solana Devnet. Test with mock USDC and TestFoils NFT collection.
Mainnet Plans
Before mainnet launch, several key milestones must be completed:
External Security Audit
Required before mainnet deployment. Third-party audit of smart contract and frontend code.
Collector Crypt Integration
Partnership with Collector Crypt for verified insured values on graded Pokemon and MTG trading cards.
Oracle Integration
Automated price feeds for collection floor prices to enable instant insured value verification.
Reputation System
On-chain reputation tracking for borrowers and lenders to enable better loan matching and rates.
Stay updated: Follow our progress on X (Twitter) for the latest announcements on mainnet launch and new feature releases.
Last updated: January 2026
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