Kadia DEX: fees

Draft

This page describes the v1 contracts and a protocol fee that is decided but not yet in the contracts. The figures marked as launch parameters are each market’s defaults, fixed when the market is created. They come from the DEX design specification and can still change before launch.

Source: kadia-dex docs/guide/fees.md at commit 4b2bbee (4b2bbeeff4c2df397d4090a1214542923338941c).

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)	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 in v1. You pay the execution fee (up to your cap), and rounding always favours the pool.

Kadia

Kadia earns nothing from the v1 contracts except what its own settler makes, like any other settler. There’s no token.

Decided, not yet in the contracts: a 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 isn’t final. The working choice is recorded in the DEX’s protocol-fee decision.