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Sponsorship Models

VelumX supports multiple implementation patterns to accommodate various business models, from zero-fee onboarding to subsidized protocol interactions.

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1. User-Settled Sponsorship (USER_PAYS)

This is the standard model for existing DeFi protocols where the user already holds a SIP-010 token and wishes to avoid acquiring STX.

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Key Characteristics

  • Fee Settlement: User pays a nominal infrastructure fee in a supported asset (e.g., USDCx).
  • Relayer Role: Automatically converts the token fee to STX gas and broadcasts the transaction.
  • Developer Impact: Zero cost to the dApp developer.

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Implementation Pattern

The SDK’s sponsor() method calculates the exact settlement amount required based on real-time oracle data.

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2. Full Developer Sponsorship (DEVELOPER_SPONSORS)

Ideal for “Day 0” onboarding where the user holds no assets. The project developer subsidizes 100% of the transaction cost.

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Key Characteristics

  • Fee Settlement: The developer’s derived relayer node settles the STX fee directly.
  • User UX: Pure gasless experience. User pays $0 and 0 tokens.
  • Developer Impact: Consumes the developer’s STX gas tank on the relayer node.

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3. High-Impact Use Cases

The VelumX architecture is fundamentally asset-agnostic and can be applied to any interaction on the Stacks blockchain.

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Vertical Integrations

VerticalImplementation Detail
BridgesWithdraw cross-chain assets (e.g., sBTC, USDCx) without holding native STX.
DEX / AMMExecute swaps and provide liquidity using only the traded pair.
NFT MarketplacesMint and transfer collectibles with zero-friction onboarding.
Governance / DAOsIncrease voting participation by removing the gas cost barrier.

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Custom Implementation Guide

To integrate VelumX into your custom smart contract, ensure your public functions accept the following standardized parameters: 
(define-public (my-gasless-function
    (fee-amount uint)
    (relayer principal)
    (fee-token <sip-010-trait>)
    ;; Your business parameters here
)
  1. Prioritize Fee Transfer: Always execute the fee-token transfer to the relayer as the first step.
  2. Execute Business Logic: proceed with your contract’s primary state changes.
  3. Atomic Completion: Ensure the entire sequence is wrapped in a single response to guarantee atomicity.