Getting started
Introduction
Plumb lets you borrow PLMB, a dollar stablecoin, against JitoSOL at an annual interest rate you choose.
Plumb is a lending protocol on Solana with one product: a dollar you mint against staked SOL. You deposit JitoSOL into a trove, choose an interest rate between 1% and 16% a year, and borrow PLMB. Your JitoSOL keeps earning staking rewards while it backs the loan.
Every PLMB is backed by JitoSOL held by the Plumb program, and anyone can redeem PLMB for a dollar's worth of that JitoSOL. Redemptions always start with the troves that pay the lowest rate. That is the trade every borrower makes: a lower rate costs less and is redeemed sooner.
BorrowOpen a trove with JitoSOL, choose a rate and mint PLMB. Repay and close whenever you like.EarnDeposit PLMB in the stability pool for 70% of the interest every borrower pays, plus JitoSOL from liquidations.RedeemTurn PLMB into a dollar of JitoSOL at any time, for a fee of at least 0.5%.LiquidateAnyone can close a trove below 150%. The pool repays its debt and takes its collateral.
How the dollar holds
- The floor. When PLMB trades below $1 minus the redemption fee, buying it and redeeming it for JitoSOL pays, and every redemption removes PLMB from circulation. The fee is never less than 0.5%, so the floor sits at $0.995 or higher.
- The ceiling. Above $1 nothing in the protocol works in reverse. Borrowers mint more PLMB and sell it, which brings the price back more slowly. The ceiling is soft.
- The backing. A trove must keep collateral worth at least 150% of its debt. Below that anyone can liquidate it, and the stability pool repays the debt.
The parts
| Part | What it is |
|---|---|
| PLMB | The stablecoin, with six decimals. Only the program mints it, and only against collateral. |
| Trove | Your position: JitoSOL collateral, PLMB debt and a rate. One per wallet. |
| Rate | One of sixteen annual rates, 1% to 16%. Interest accrues every second and is added to your debt. |
| Stability pool | PLMB deposits that repay liquidated debt and earn most of the interest. |
| Price | JitoSOL is valued at the lower of its stake value and its market price, both read on chain. |
Where to go next
- New to Plumb: the Quickstart walks through opening a trove in the app.
- Looking for a number: Parameters lists every limit and fee.
- Building on Plumb: start with the HTTP API and the program reference.
Plumb's mechanism follows Liquity v2: borrower-set rates, redemptions ordered by rate, and a stability pool for the collateral. The program is written for Solana from the ground up.
# Introduction Plumb lets you borrow PLMB, a dollar stablecoin, against JitoSOL at an annual interest rate you choose. Plumb is a lending protocol on Solana with one product: a dollar you mint against staked SOL. You deposit JitoSOL into a trove, choose an interest rate between 1% and 16% a year, and borrow PLMB. Your JitoSOL keeps earning staking rewards while it backs the loan. Every PLMB is backed by JitoSOL held by the Plumb program, and anyone can redeem PLMB for a dollar's worth of that JitoSOL. Redemptions always start with the troves that pay the lowest rate. That is the trade every borrower makes: a lower rate costs less and is redeemed sooner. :::figure strings | Each string is a rate, 1% to 16%. Its length is the PLMB owed at that rate and each knot is a trove. The vermilion line is a new trove at 6%. Amounts are an example. ## What you can do :::cards - [Borrow](/docs/troves): Open a trove with JitoSOL, choose a rate and mint PLMB. Repay and close whenever you like. - [Earn](/docs/stability-pool): Deposit PLMB in the stability pool for 70% of the interest every borrower pays, plus JitoSOL from liquidations. - [Redeem](/docs/redemptions): Turn PLMB into a dollar of JitoSOL at any time, for a fee of at least 0.5%. - [Liquidate](/docs/liquidations): Anyone can close a trove below 150%. The pool repays its debt and takes its collateral. ::: ## How the dollar holds - **The floor.** When PLMB trades below $1 minus the redemption fee, buying it and redeeming it for JitoSOL pays, and every redemption removes PLMB from circulation. The fee is never less than 0.5%, so the floor sits at $0.995 or higher. - **The ceiling.** Above $1 nothing in the protocol works in reverse. Borrowers mint more PLMB and sell it, which brings the price back more slowly. The ceiling is soft. - **The backing.** A trove must keep collateral worth at least 150% of its debt. Below that anyone can liquidate it, and the stability pool repays the debt. ## The parts | Part | What it is | | --- | --- | | PLMB | The stablecoin, with six decimals. Only the program mints it, and only against collateral. | | Trove | Your position: JitoSOL collateral, PLMB debt and a rate. One per wallet. | | Rate | One of sixteen annual rates, 1% to 16%. Interest accrues every second and is added to your debt. | | Stability pool | PLMB deposits that repay liquidated debt and earn most of the interest. | | Price | JitoSOL is valued at the lower of its stake value and its market price, both read on chain. | > [!WARNING] > Borrowing against JitoSOL can end in liquidation, and a redemption can shrink your trove without asking. Read [Risks](/docs/risks) before you open a trove. ## Where to go next - New to Plumb: the [Quickstart](/docs/quickstart) walks through opening a trove in the app. - Looking for a number: [Parameters](/docs/parameters) lists every limit and fee. - Building on Plumb: start with the [HTTP API](/docs/api) and the [program reference](/docs/program). Plumb's mechanism follows Liquity v2: borrower-set rates, redemptions ordered by rate, and a stability pool for the collateral. The program is written for Solana from the ground up.