vyfi

VyFi DEX

tx3 protocol for VyFi — AMM DEX order submission on Cardano.

Status: WIP — This tx3 off-chain implementation is under testing and may not cover all edge cases yet.

Overview

VyFi is an AMM-based DEX on Cardano using a two-step order model:

1. User submits order — sends funds + datum to a pool-specific order script address (no scripts executed)
2. Batcher processes order — VyFi infrastructure consumes the order + pool UTxO and distributes results

This tx3 implements the user-facing transactions only (step 1). Each pool has its own order address, provided dynamically per call via the OrderScript party.

Transactions

Transaction	Description
swap_a_to_b	Swap ADA for a token
swap_b_to_a	Swap a token for ADA
add_liquidity	Deposit ADA + tokens into a liquidity pool
remove_liquidity	Withdraw liquidity by sending LP tokens

Important Considerations

• No script execution on submission: Order submissions are plain payments with inline datums — no validators are invoked. This means no collateral is needed.
• Pool-specific order address: The OrderScript party must be set to the correct order address for each pool. Pool data is available from the VyFi API.
• Process fee: VyFi batchers charge a process fee (currently 1.9 ADA) included in each order.
• User credentials format: The user_creds parameter is a 56-byte value: payment credential (28 bytes) concatenated with staking credential (28 bytes).
• Batcher-side not implemented: This tx3 does not cover batcher operations (consuming orders, updating pool state). Only user-facing order submission and cancellation.

Caller Preparation

All transactions

• user_creds: Bytes — 56-byte hex value: payment credential (28 bytes) + staking credential (28 bytes). Must be constructed from the user's wallet address by extracting the raw credential hashes and concatenating them.
• OrderScript party address — Must be set to the correct pool-specific order address. Query the VyFi API (/lp?networkId=1) for pool data including the order address.

swap_b_to_a / remove_liquidity

• order_ada: Int — The ADA amount to include in the order UTxO (min UTxO + process fee). Must account for the tokens being sent.

add_liquidity

• desired_lp: Int — The desired LP token amount. Must be calculated based on current pool ratio.

Pool data (query VyFi API before any transaction)

• Pool order address (for OrderScript party)
• Token policy ID and asset name (for token parameters)
• Current pool ratio (for calculating swap amounts, LP tokens)
• Process fee: currently 1.9 ADA

tx3 Limitations

No significant tx3 limitations were encountered. Order submissions are plain payments with inline datums — no script execution, no complex redeemers. The two-step model means all validator logic runs on the batcher side (not implemented in this tx3).

Smart Contracts

• Pool data source: VyFi API (/lp?networkId=1)