Getting started
Introduction
Tack swaps floating SOL-PERP funding for a fixed rate, to a weekly maturity, settled in USDC on Solana.
What you can do
Turn the funding a Phoenix short collects into a known rate until a weekly maturity.
Pay fixedPay a fixed rate and receive SOL-PERP funding: a view that funding will run above it.
Quote a ratePost a whole lot at your own rate, with your collateral behind it, and wait for a taker.
Build on itRead markets, quotes and positions, and build unsigned transactions over HTTP.
How a swap works
A Tack swap has two legs on the same notional, in USDC:
- The fixed leg is a rate a year, agreed when the swap opens and unchanged until it closes.
- The floating leg is SOL perp funding on Phoenix, as Phoenix records it every hour.
The side that pays fixed receives the floating leg; the side that receives fixed pays it. Each time Phoenix records an hour of funding, Tack writes the record on chain as a checkpoint and settles the difference between the two legs in USDC, out of collateral both sides locked when the swap opened. At maturity, a Friday at 08:00 UTC, the last funding record settles the swap and each side withdraws what its balance holds.
payer, at each checkpoint N × (ΔF − K × Δt)
receiver the negativeN is the notional, ΔF the floating leg since the last checkpoint, K the fixed rate and Δt the time between checkpoints. Settlement has the exact arithmetic.
What Tack is built from
- Whole-lot quotes. A maker posts a notional, a fixed rate and collateral. A taker accepts the lot as it stands. Nothing is matched automatically and nothing fills in part; in the app the quotes hang on a mast at the height of their rate.
- Funding read from chain. The program reads Phoenix's SOL account directly: its cumulative funding, its mark price and its open interest. There is no price oracle of Tack's own and no key that can type in a funding value.
- One swap, two traders. Each swap holds two collateral balances and moves USDC only between them. There is no pool, no insurance fund and no loss shared with anyone else.
- No trading fees. Tack charges no fee on a trade and pays no liquidation bounty. You pay Solana transaction fees and rent for the accounts a quote or a position opens.
- Your keys sign. USDC sits in each market's vault, owned by the program. The Tack service builds unsigned transactions; your wallet signs them, and the app checks every one before it asks.