FlowFuel

Problem Statement

FlowFuel is a milestone-driven crowdfunding + NFT platform built on Flow. Creators launch campaigns made of sequential milestones and mint a fixed supply of Milestone NFTs that represent backer ownership of those campaigns. Fans buy these NFTs to fund projects; those funds accumulate in on-chain campaign vaults and are released to creators per-milestone. Every Milestone NFT carries royalty metadata so creators continue to earn royalties on every secondary sale via Flow’s NFTStorefrontV2—no extra marketplace logic required.Key user flowsCreator creates a campaign (title, description, image, goal, milestones, total NFTs).Fan buys one or more Milestone NFTs at a per-NFT price = goalAmount / totalNFTs.Payments go into a campaign-specific FlowToken vault managed by the contract.When enough funds are collected, creators can withdraw milestone-sized payouts (goalAmount / milestones.length), with the system emitting events.Milestone NFTs are tradable on marketplaces that support Flow’s MetadataViews.Royalties standard; NFTStorefrontV2 pulls royalty info from the NFT metadata and pays royalties automatically on resale.

Solution

How it’s made High-level architecture Cadence contractsMilestoneNFT.cdc — custom NFT contract that:Implements NonFungibleToken, MetadataViews (Display & Royalties), and ViewResolver.Resolver.Stores NFT fields: id, name, description, image (HTTP URI), royaltyReceiver capability, and royaltyCut.Collection conforms to ViewResolver.ResolverCollection so off-chain UIs/marketplaces can resolve Display and Royalties.CampaignManager.cdc — campaign lifecycle logic:Create campaigns, track funding, mint milestone NFTs, and manage campaign vaults (dictionary keyed by campaign ID).contributeAndMint: verifies payment equals NFT price, deposits funds into campaign vault, mints NFT to buyer while embedding creator royalty capability and cut.Vault management: campaign vaults are stored as actual FlowToken.Vault resources inside the contract (campaignVaults: @{UInt64: FlowToken.Vault}), removed and re-inserted when depositing/withdrawing to respect Cadence resource rules.Milestone withdrawals: withdrawNextMilestone withdraws exactly one milestone amount if enough funds exist; emits MilestoneWithdrawn.Safe patterns: strict pre/assert checks and careful <-/<-! resource moves to avoid leaks.Marketplace integrationRelies on the global NFTStorefrontV2 contract (already deployed).Helper transactions:SetupStorefront (user-level) — create storefront in user account storage.CreateListing — seller issues provider capability from their MilestoneNFT collection and calls Storefront.createListing(...) with saleCuts and salePaymentVaultType.PurchaseListing — buyer provides a FlowToken vault to the purchase API; NFTStorefrontV2 distributes saleCuts (including royalties) automatically.Royalties are surfaced by the NFT via MetadataViews.Royalties; NFTStorefrontV2 reads these views and transforms them into saleCuts at listing time.Nuance: saleCut supports only one token type per listing; to accept multi-token saleCuts, integrate the FungibleTokenSwitchboard pattern.Frontend & UXNext.js app with Flow Client Library (FCL) for wallet discovery and transaction signing.React hooks map 1:1 to Cadence scripts/transactions:useCreateCampaign → CreateCampaign.cdcuseContributeAndMint → ContributeAndMint.cdcuseSetupNFTCollection → SetupNFTCollection.cdcuseSetupStorefront → SetupStorefront.cdcuseListNFT → CreateListing.cdcuseBuyNFT → PurchaseListing.cdcuseCampaigns / useCampaign / useUserNFTs → read-only scripts (GetCampaigns, GetCampaign, GetNFTMetadata, GetNFTCollection)Off-chain assets (images + metadata) are stored on IPFS/Pinata and referenced by HTTP URIs in the NFT Display metadata.