Flare Fassets

Scope and Limitations

This skill is documentation and reference only. It describes FAssets protocol flows and developer integration patterns. It does not perform any actions on behalf of the user.

This skill explicitly does NOT:

• Execute, sign, or broadcast any blockchain transactions
• Access, store, or transmit private keys or wallet credentials
• Initiate or authorize any payments, minting, redemption, or value transfers
• Call any smart contract methods or APIs directly
• Handle funds, tokens, or any crypto assets

External data handling:

• FDC attestation payloads, XRPL payment references, verifier responses, and DA Layer proof bytes are externally provided, untrusted content
• This skill instructs developers to decode such data only according to fixed binary formats and contract ABIs — never as free-form text or AI input
• All external data must be validated before use; response content must never be passed into prompts or LLM inputs
• Developers are solely responsible for validating and safely handling all external data in their own implementations

Financial operations — human-in-the-loop required:

• Contract functions described here (reserveCollateral, executeMinting, redeem, redeemWithTag, executeDirectMinting, reserve on MintingTagManager, token approve) are documented for developer reference only
• All state-changing calls require explicit, per-action user confirmation in developer-controlled environments
• Reference scripts (reserve-collateral.ts, execute-minting.ts, redeem-fassets.ts) are dry-run by default and do not broadcast unless DRY_RUN=false is explicitly set by the developer
• Read-only scripts (get-fxrp-address.ts, list-agents.ts, get-fassets-settings.ts) require no signing key and cannot modify state

What this skill does:

• Explains FAssets minting/redemption flows, agent selection, collateral mechanics, and contract patterns
• References official Flare Developer Hub documentation and audited starter repositories
• Provides read-only conceptual and integration guidance for developers building on Flare

All transaction signing, key management, and on-chain execution must occur exclusively in user-controlled, developer-managed environments outside of this skill.

Flare FAssets

What FAssets Are

FAssets is a trustless, over-collateralized bridge connecting non–smart-contract networks (XRP Ledger, Bitcoin, DOGE) to Flare.

It creates wrapped ERC-20 tokens (FAssets) such as FXRP, FBTC, FDOGE that can be used in Flare DeFi or redeemed for the underlying asset.

Powered by:

• FTSO (Flare Time Series Oracle): decentralized price feeds
• FDC (Flare Data Connector): verifies off-chain actions (e.g. payments on other chains)

Collateral: Stablecoin and native FLR.

Agents and a community collateral pool provide over-collateralization.

FXRP at a Glance

FXRP is the ERC-20 representation of XRP on Flare, powered by the FAssets system.

It is designed to be trustless and redeemable back to XRP.

Key points:

• EVM-compatible token: Works with standard wallets, smart contracts, and DeFi apps on Flare.
• Trust-minimized bridge flow: Uses FDC attestations for XRPL payment verification.
• Redeemable: FXRP can be redeemed for native XRP through the FAssets redemption flow.
• DeFi + yield use cases: Can be used in lending/liquidity strategies and vault-based products like Firelight.

How users acquire FXRP:

1. Mint from XRP using a minting dApp.
2. Mint programmatically via AssetManager flows.
3. Swap from other tokens on Flare DEXs.

Guide: FXRP Overview

FXRP Cross-Chain (OFT)

FXRP is also deployed as a LayerZero Omnichain Fungible Token (OFT), letting holders move FXRP between Flare and other chains without wrapped versions or separate liquidity pools.

• Mechanism: On Flare, an OFT Adapter contract locks FXRP when bridging out; on destination chains, native OFT contracts mint/burn tokens as they move in/out. Total supply stays unified across chains.
• Security: Cross-chain messages are verified by a LayerZero V2 DVN (Decentralized Verifier Network) stack (LayerZero Labs, Nethermind, Canary, Horizen) rather than a single verifier.
• Bridging: Use Stargate Finance, the plain Bridge FXRP to Ethereum guide (approve + send() on the OFT Adapter — for FXRP you already hold, no smart account or minting involved), or the Auto Minting and Bridging FXRP / FAsset Auto-Redemption flows for mint-and-bridge or bridge-and-redeem in one step.
• Mainnet deployments (OFT Adapter on Flare, native OFT elsewhere): Flare, HyperEVM, HyperCore, Ethereum Mainnet, Base, BNB Smart Chain, Monad, Katana — see FXRP OFT Deployments for current addresses; do not hardcode without verifying against that page or a block explorer.

Guide: FXRP Omnichain Fungible Token (OFT)

Key Participants

FAsset Workflow

Minting (Core Vault, XRP)

Minting model change: The standard FXRP minting path is now a single XRPL payment to the Core Vault (what was previously called "direct minting"). The older collateral-reservation flow (reserve collateral → pay agent → executeMinting) is archived/legacy — see Standard Minting (legacy) below and the Standard Minting (Archived) reference.

Minting requires only a single XRPL payment to the Core Vault address. No collateral reservation step is needed.

1. Encode the minting parameters (recipient, optional executor) via XRP destination tag (using MintingTagManager) or a binary memo field. For the 32-byte memo form, encode [8-byte DIRECT_MINTING prefix 0x4642505266410018][4-byte zero padding][20-byte recipient]; the 48-byte form (0x4642505266410021 prefix) also encodes an executor.
2. Send the XRPL payment to the Core Vault address (AssetManager.directMintingPaymentAddress()).
3. An executor calls executeDirectMinting (or executeDirectMintingWithData for smart-account hash-commitment memos) on Flare to finalize → FXRP is minted to the recipient.

Fees: Percentage-based minting fee (with a minimum floor) + a flat executor fee, both deducted from the payment. If the payment only covers the minting fee, the executor receives nothing; if it is below the minimum minting fee, no FAssets are minted and the entire payment goes to the fee receiver. Rate limits (hourly/daily caps, large-mint delays) throttle but do not reject mints.

Skill guide: direct-minting-guide.md

Developer guides (TypeScript/viem, flare-viem-starter):

• Mint FXRP — memo-based path (32-byte memo with 0x4642505266410018 prefix + recipient)
• Mint FXRP with Tag — destination-tag path (reserve via MintingTagManager, bind recipient, reuse for subsequent payments)

Self-Minting (Agents)

Agents can act as minters and mint FAssets directly from their own vaults. When an agent self-mints, it pays the amount on the underlying chain and executes the minting itself; the operation adds a ticket to the redemption queue alongside other users' tickets. Agents can create non-public vaults usable only for self-minting.

Redemption

Users redeem FAssets for the original underlying asset at any time (flow is request → agent pays out on underlying chain).

Redeem by Amount: redeemAmount(amountUBA, ...) redeems an arbitrary amount in UBA (not whole lots). Validate against minimumRedeemAmountUBA(); partial fulfillment emits RedemptionAmountIncomplete. Developer guide (TypeScript/viem): Redeem FXRP by Amount.

Redeem with Tag (XRP): redeemWithTag lets redeemers specify an XRP destination tag, enabling redemption to exchange addresses that require one. Confirmed via confirmXRPRedemptionPayment; defaults via xrpRedemptionPaymentDefault. Gated by redeemWithTagSupported flag. Developer guide (TypeScript/viem): Redeem FXRP with Tag.

Core Vault (CV)

Per-asset vault that improves capital efficiency: agents can deposit underlying into the CV to free collateral.

Multisig on the underlying network; governance can pause.

Not agent-owned.

Contracts and Addresses — Get at Runtime

FlareContractsRegistry (same on all Flare networks): 0xaD67FE66660Fb8dFE9d6b1b4240d8650e30F6019.

This address is correct; always double-check it (and any contract addresses) on the official Retrieving Contract Addresses guide on the Flare Developer Hub.

Use it as the trusted source to resolve other contract addresses (e.g. getContractAddressByName(), getAllContracts()).

Do not hardcode AssetManagerController, AssetManager, or FXRP addresses.

They differ per network (Coston2, Songbird, Flare mainnet).

Resolve them at runtime via the registry.

To get the FXRP address:

1. Query the FlareContractsRegistry with getContractAddressByName("AssetManagerFXRP") — the returned address is the AssetManager (FXRP) contract address.
2. Attach the IAssetManager interface to that address (or use it as your AssetManager instance).
3. Call fAsset() on the AssetManager to get the FXRP ERC-20 token address.

Same pattern for other FAssets (FBTC, etc.) using their corresponding registry keys.

AssetManagerController is also available from the registry when needed.

Guide: Get FXRP Address — e.g. const assetManager = await getAssetManagerFXRP(); const fasset = await assetManager.fAsset();

Skill resource script: scripts/get-fxrp-address.ts — gets FXRP address at runtime via FlareContractsRegistry → getContractAddressByName("AssetManagerFXRP") → fAsset().

Uses ethers; set FLARE_RPC_URL or pass your network RPC. Security: Review the script before running; execute only in an isolated environment (e.g. local dev or sandbox). Run with npx ts-node scripts/get-fxrp-address.ts (or in a Hardhat project with yarn hardhat run scripts/get-fxrp-address.ts --network coston2).

Developer Integration (High Level)

Minting via Core Vault (XRP Only)

The standard single-transaction minting path (formerly "direct minting"). No collateral reservation required. The contract-level entry points still use the directMinting / executeDirectMinting names.

1. Get Core Vault address: Call AssetManager.directMintingPaymentAddress().
2. Get fee parameters:
   • getDirectMintingMinimumFeeUBA() — minimum minting fee floor
   • getDirectMintingFeeBIPS() — minting fee percentage
   • getDirectMintingExecutorFeeUBA() — flat executor fee
3. Encode parameters in the XRPL payment via destination tag (using MintingTagManager) or binary memo field.
4. Send payment on XRPL to the Core Vault address.
5. Executor calls executeDirectMinting on Flare after othersCanExecuteAfterSeconds if preferred executor is inactive.

Rate limits (tumbling windows): Direct minting uses clock-aligned tumbling windows (hourly: 3600s aligned to UTC, daily: 86400s aligned to 00:00 UTC). Mints over the cap are delayed, not rejected. Query:

• getDirectMintingHourlyLimitUBA(), getDirectMintingDailyLimitUBA() — caps
• getDirectMintingHourlyLimiterState(), getDirectMintingDailyLimiterState() — raw window state (advance off-chain for live values)
• getDirectMintingsUnblockUntilTimestamp() — if future, the hourly/daily limiter is temporarily disabled by governance (does not bypass the large-mint delay)
• assetMintingGranularityUBA() — granularity to convert AMG units to UBA
• getDirectMintingLargeMintingThresholdUBA(), getDirectMintingLargeMintingDelaySeconds() — a mint strictly above the threshold is delayed independently of the hourly/daily windows Watch for DirectMintingDelayed (hourly/daily) or LargeDirectMintingDelayed (large-mint threshold) events; the binding rule is whichever pushes executionAllowedAt furthest out. Query directMintingDelayState(transactionId) for current state, and call markUnblockedDirectMintingAllowed(transactionId) after a governance unblock (DirectMintingsUnblocked) to reset the executor exclusive window. Developer guide: Check Minting Limits. Full troubleshooting: Minting Troubleshooting

MintingTagManager (access via AssetManager.getMintingTagManager()):

• reserve() — payable; reserves a tag NFT, returns tag ID
• setMintingRecipient(tagId, recipient) — owner only; sets FAsset recipient
• reservationFee() — returns fee in native tokens
• reservedTagsForOwner(owner) — returns all tag IDs for an address
• transfer(to, tagId) — transfers tag; resets recipient and executor
• mintingRecipient(tagId) — returns current recipient
• allowedExecutor(tagId) — returns active executor (address(0) = anyone)
• setAllowedExecutor(tagId, executor) — owner only; restricts execution to executor (10-min cooldown; cleared on transfer)
• transferFrom(from, to, tagId) — ERC-721 transfer; resets recipient to new owner, clears allowed executor, tag ID unchanged. Use to rotate custody or hand a tag to another account. Developer guide: Transfer a Minting Tag

Skill guide: direct-minting-guide.md

Standard Minting (legacy)

Archived. The collateral-reservation flow below is the legacy minting path, kept for reference and historical integrations. New integrations should use Minting via Core Vault above. See the Standard Minting (Archived) reference. reserveCollateral / executeMinting remain on the AssetManager interface.

1. Reserve collateral: Call reserveCollateral(agentVault, lots, feeBIPS, executor) on AssetManager.

Pay CRF via collateralReservationFee(lots).

Use CollateralReserved event for collateralReservationId, payment reference, and deadlines. 2. Underlying payment: User sends underlying asset to agent's underlying-chain address with the payment reference from the event.

Must complete before lastUnderlyingBlock and lastUnderlyingTimestamp. 3. Proof: Use FDC to get attestation/proof for the payment (e.g. Payment attestation type). 4. Execute minting: Call executeMinting(proof, collateralReservationId) on AssetManager.

Agent selection: Use getAvailableAgentsDetailedList (or equivalent), filter by free collateral lots and status, then by fee (e.g. feeBIPS).

Prefer agents with status NORMAL.

Read FAssets Settings

FAssets operational parameters (lot size, asset decimals, collateral ratios, fees, thresholds) are read from the AssetManager via getSettings(). Two official approaches:

Solidity (Hardhat)

Use @flarenetwork/flare-periphery-contracts for typed contract access:

// ContractRegistry.getAssetManagerFXRP() resolves the AssetManager at runtime
IAssetManager am = ContractRegistry.getAssetManagerFXRP();
IAssetManager.Settings memory s = am.getSettings();
// s.lotSizeAMG — lot size in AMG units
// s.assetDecimals — decimal places for the FAsset
uint256 lotSizeXRP = s.lotSizeAMG / (10 ** s.assetDecimals);

Run the interaction script:

npx hardhat run scripts/fassets/getLotSize.ts --network coston2

Expected output (example):

FAssetsSettings deployed to: 0x40deEaA76224Ca9439D4e1c86F827Be829b89D9E
Lot size: 20000000 | Decimals: 6 | Lot size in XRP: 20

Guide: Read FAssets Settings (Solidity)

Node.js (TypeScript + viem)

Use @flarenetwork/flare-wagmi-periphery-package — this is the recommended package for TypeScript/Node.js scripts. It provides all typed contract ABIs for Flare networks (including Coston2) and integrates directly with viem, eliminating the need for manual ABI definitions.

Install dependencies:

npm install --save-dev typescript viem @flarenetwork/flare-wagmi-periphery-package

Key steps:

1. Import the coston2 namespace from @flarenetwork/flare-wagmi-periphery-package — gives you typed ABIs for the Coston2 network.
2. Create a viem public client connected to Flare Testnet Coston2.
3. Resolve the FXRP AssetManager address via FlareContractRegistry (getContractAddressByName("AssetManagerFXRP")).
4. Call getSettings() → read lotSizeAMG and assetDecimals → compute lot size in XRP.
5. Resolve FtsoV2 address and call getFeedById with the XRP/USD feed ID (0x015852502f55534400000000000000000000000000) to get the current price.
6. Calculate lot value in USD.

Expected output (example): Lot Size: 10 FXRP · XRP/USD: ~2.84 · Lot value: ~$28.44

Guide: Read FAssets Settings (Node.js)

Skill script: scripts/get-fassets-settings.ts — reads lot size, decimals, and XRP/USD price (uses ethers; for new projects prefer viem + @flarenetwork/flare-wagmi-periphery-package as shown in the Node.js guide above).

Redeeming

Request redemption (burn FAssets on Flare); the chosen agent pays out the underlying asset on the underlying chain.

See FAssets Redemption and Redeem FAssets for the full flow (redemption request, queue, agent payout, optional swap-and-redeem / auto-redeem).

Prerequisites (from Flare docs): Flare Hardhat Starter Kit, @flarenetwork/flare-periphery-contracts, and for XRP payments the xrpl package.

Gasless FXRP Payments

FXRP supports gasless (meta-transaction) transfers via EIP-712 signed payment requests. Users sign off-chain; a relayer submits on-chain and pays gas.

Skill guide: agent-details-guide.md — read agent name, description, icon URL, and terms of use from AgentOwnerRegistry.

Guide: Read FAssets Agent Details

Skill guide: gasless-payments-guide.md — full walkthrough (architecture, GaslessPaymentForwarder contract, relayer service, replay protection, one-time approval setup).

Guide: Gasless FXRP Payments

IAssetManager — Key API Groups

Information: getSettings(), getAgentInfo(agentVault), getCollateralTypes(), collateralReservationFee(lots), collateralReservationInfo(collateralReservationId), fAsset()

Direct Minting Settings: directMintingPaymentAddress(), getDirectMintingMinimumFeeUBA(), getDirectMintingFeeBIPS(), getDirectMintingExecutorFeeUBA(), getDirectMintingOthersCanExecuteAfterSeconds(), getDirectMintingHourlyLimitUBA(), getDirectMintingDailyLimitUBA(), getDirectMintingLargeMintingThresholdUBA(), getDirectMintingLargeMintingDelaySeconds(), getDirectMintingFeeReceiver()

Redeem With Tag Settings: minimumRedeemAmountUBA(), getMintingTagManager()

Redemption: redeem(lots, underlyingAddress, executor), redeemAmount(amountUBA, underlyingAddress, executor), redeemWithTag(amountUBA, underlyingAddress, executor, destinationTag), redemptionPaymentDefault(proof, requestId)

Agents: getAllAgents(start, end), getAvailableAgentsList(start, end), getAvailableAgentsDetailedList(start, end)

Redemption Queue: redemptionQueue(firstRedemptionTicketId, pageSize), agentRedemptionQueue(agentVault, firstRedemptionTicketId, pageSize)

Collateral Reservation & Minting Execution: reserveCollateral(agentVault, lots, maxFeeBIPS, executor), executeMinting(IPayment.Proof proof, collateralReservationId), executeDirectMinting(IXRPPayment.Proof proof), executeDirectMintingWithData(IXRPPayment.Proof proof, bytes data) (for smart-account custom instructions; data = ABI-encoded PackedUserOperation; only valid for smart-account targets)

Core Vault: getCoreVaultManager(), getCoreVaultDonationTag(), getCoreVaultMinimumAmountLeftBIPS(), getCoreVaultTransferTimeExtensionSeconds(), getCoreVaultTransferFeeBIPS(), getCoreVaultMinimumRedeemLots(), getCoreVaultRedemptionFeeBIPS()

Reference: IAssetManager | IMintingTagManager

Terminology

• Underlying network / underlying asset: Source chain and its native asset (e.g. XRPL, XRP).
• Lot: Smallest minting unit; size from AssetManager/FTSO (see "Read FAssets Settings" in reference).
• Backing factor: Minimum collateral ratio agents must maintain.
• CRF: Collateral Reservation Fee. UBA: Smallest unit of the underlying asset (e.g. drops for XRP).
• Direct Minting: The single-XRPL-payment minting path via Core Vault (XRP only), now the standard FXRP minting model (docs call it simply "Minting"). No collateral reservation required. Contract entry points keep the directMinting / executeDirectMinting names.
• Self-minting: An agent minting FAssets from its own vault; adds a redemption-queue ticket. Can use non-public vaults.
• Standard Minting (legacy): The archived collateral-reservation flow (reserveCollateral → agent payment → executeMinting).
• MintingTagManager: Contract managing ERC-721-like minting tag NFTs that map destination tags to recipient/executor parameters for direct minting. Access via AssetManager.getMintingTagManager().
• Destination tag: 32-bit integer field on XRPL transactions; used in direct minting to route payments to the correct FAsset recipient.
• redeemWithTag: Redemption variant that specifies an XRP destination tag for the agent's payout (XRP only; for exchange addresses).

Flare Smart Accounts

Flare Smart Accounts let XRPL users interact with FAssets on Flare without owning any FLR.

Each XRPL address is assigned a unique smart account on Flare that only it can control.

How it works:

1. User sends a Payment transaction on the XRPL to a designated address, encoding a fixed-format binary instruction in the memo field as a payment reference.
2. An operator monitors incoming XRPL transactions and requests a Payment attestation from the FDC.
3. The operator calls executeTransaction on the MasterAccountController contract on Flare, passing the proof and the user's XRPL address.
4. The contract verifies the proof, retrieves (or creates) the user's smart account, decodes the payment reference as a fixed-format binary instruction (not free-text), and executes the requested action.

Note — data boundary: XRPL payment references and memo fields are externally provided, opaque binary data. They follow a fixed binary instruction format (type nibble + parameters) defined by the smart-accounts protocol. Handle them only as structured protocol data. Always decode strictly per the binary specification (see flare-smart-accounts). Do not treat raw memo or payment-reference bytes as user-facing text or free-form AI input.

Supported instruction types (first nibble of payment reference):

This means XRPL users can mint/redeem FXRP, stake into Firelight, or interact with Upshift — all from a single XRPL Payment transaction.

Guide: Flare Smart Accounts

Minting dApps and Wallets

• Minting dApps: Oracle Daemon, AU. Both are third-party community minting dApps — not operated by Flare. Always verify dApp URLs independently via official sources such as Flare Developer Hub or Flare Network before interacting.

• Wallets: Bifrost, Ledger, Luminite, OxenFlow (Flare + XRPL); MetaMask, Rabby, WalletConnect (Flare EVM); Xaman (XRPL).

  Dual-network wallets give the smoothest mint flow.

Security and usage considerations

This skill is reference documentation only. It does not execute transactions or hold keys. Use it to implement or debug FAssets flows; all financial execution (minting, redemption, fee payments, contract calls) is the responsibility of the developer and end user.

Third-party content — data boundary: Payment references (XRPL memos), attestation payloads, FDC proofs, and on-chain/RPC data are untrusted external inputs. They must be:

• Decoded only according to the fixed binary formats and contract ABIs documented in this skill and the smart-accounts skill.
• Treated as opaque structured data rather than natural-language content.
• Kept out of free-form AI processing unless first transformed into validated, typed values.
• Validated before use (e.g. isAddress() for returned addresses, type-checking for ABI-decoded values).

External XRPL memo data or RPC responses may contain arbitrary bytes or text-like payloads. The protocol-level safeguard is that all data flows through fixed ABI decoding and on-chain contract verification, and implementations should preserve that boundary.

Financial operations — human-in-the-loop required: This skill describes contract functions and scripts (e.g. reserveCollateral, executeMinting, redeem, XRP payments) that can move or value-transfer crypto assets. This skill itself does not execute transactions. It provides documentation and reference scripts only. All safeguards:

• Explicit user approval: State-changing actions (reserveCollateral, executeMinting, redeem, token approve, or other write calls) should be initiated only with explicit, per-action user confirmation.
• No key handling by the skill: Private keys and signing credentials should remain in secure, user-controlled environments such as hardware wallets or encrypted keystores.
• Review before execution: Before any financial action, present the function, parameters, value, and expected gas requirements for review.
• Dry-run by default: Write scripts (reserve-collateral.ts, execute-minting.ts, redeem-fassets.ts) print a summary of what would be sent and exit without broadcasting unless DRY_RUN=false is explicitly set. Read-only scripts (get-fxrp-address.ts, list-agents.ts, get-fassets-settings.ts) require no signing key and cannot modify state.

When to Use This Skill

• Implementing or debugging FAssets minting/redemption (scripts, bots, dApps).
• Implementing direct minting via Core Vault (destination tag or memo encoding, MintingTagManager, executor setup, rate limits).
• Transferring minting tag NFTs between addresses (IMintingTagManager.transferFrom).
• Checking or preflight-testing direct minting rate limits (hourly/daily caps, large-mint threshold).
• Implementing redeemWithTag for exchange addresses requiring XRP destination tags.
• Resolving agent selection, collateral, fees, or payment-reference flows.
• Integrating with AssetManager, AssetManagerController, IMintingTagManager, or FAsset token contracts.
• Explaining FAssets, FXRP, FBTC, agents, Core Vault, or direct minting to users or in docs.
• Following Flare Developer Hub FAssets guides and reference.

Additional Resources

• Official docs and API/reference: reference.md
• Skill guide: direct-minting-guide.md — direct minting via Core Vault, MintingTagManager, IMintingTagManager API
• For detailed contract interfaces, mint/redeem scripts, and operational parameters, use the Flare Developer Hub links in reference.md.