Kadia DEX: fees

Draft

This page describes the contracts of the testnet markets (revision r12), including their protocol fee. The figures marked as launch parameters are each market’s defaults, fixed when the market is created. The testnet markets use them; they can still change before mainnet.

Source: kadia-dex docs/guide/fees.md at commit 28b2eba (28b2ebad314c5a32c779ca2b4093e71fe8c142ea).

A trader filling an order

Fee	Launch parameter	Paid	Goes to	Enforced by
Order fee f	30 bps	Out of your payout: you’re owed P′ · (1 − f)	Split below	Your order contract
└ Pool fee φ	20 bps	Part of f	Liquidity providers (it stays in the pool), less the protocol share: a sixth of the pool’s growth goes to the treasury	The market contract, on every swap
└ Settler margin f − φ	about 10 bps	Roughly the rest of f	Whoever settled the batch	Not enforced: it’s what’s left over
Execution fee	Up to your maxExecFee, in ERG	From your order’s ERG	The settler, who pays the miner fee from it	Your order contract, as a cap
Miner fee	Set by the settler	By the settler	Ergo miners	Ergo consensus

• You set the ceilings. Your order records the highest f you accept and your execution-fee cap, and refuses a market or settlement above them.
• The settler’s margin isn’t guaranteed. Some batches lose money and need the settler’s own inventory.
• Trading without an order pays only φ. Anyone can spend the market box directly in their own transaction and pay just the pool fee. That’s normal for arbitrage bots.
• The rent reserve isn’t a fee. It’s ERG that stays in your payout box with your tokens, to cover Ergo’s storage rent. The app shows it as “stays yours”.

Refunds and cancellations

• Cancelling with your own key costs only the miner fee.
• A refund after expiry can be built by anyone, who keeps up to your execution-fee cap. Refunds still happen without Kadia.

Adding and removing liquidity

There’s no separate LP fee. You pay the execution fee (up to your cap), and rounding always favours the pool. Through the protocol fee, liquidity providers pay a share of the pool’s growth to the treasury (below).

Kadia

Kadia earns the protocol fee below, paid to its treasury, and whatever its own settler makes, like any other settler. There’s no token.

The protocol fee

• Enforced by the market contract, so no app, bot or direct trade can avoid it on Kadia markets.
• No token. The fee goes to one treasury, in the pool’s own assets, controlled by a single control token.
• How it works:
  • At most once per block, a claim pays the treasury a share of the growth in the pool’s size per LP share since the last claim.
  • It’s taken from both reserves, so the price doesn’t move.
  • Swap prices and order payouts are unchanged; liquidity providers see their pool growing a little more slowly.
• You pay only on growth while you hold LP. A new LP doesn’t pay for growth before they joined, and leaving before a claim doesn’t skip it.
• The share: each testnet market records a protocol share of 1,667 bps (one sixth) of that growth, fixed when the market was created, and the registry admits no market with a higher share. On testnet the markets pay the treasury’s share now. The share for mainnet isn’t final.