# Fixed Price LBP

A Fixed Price LBP is a Liquidity Bootstrapping Pool that keeps a constant exchange rate between the project token and the reserve token for the whole sale. Unlike standard LBPs, there is no scheduled weights changes.

# When to use it?

Use a Fixed Price LBP when you want a constant-rate token sale: one project token always costs the same amount of reserve token (1 TOKEN = 10 USDC). Use a weight-shifting LBP when you want price discovery (check Token Launches).

# How it works?

• Constant price: The pool uses a fixed rate (e.g. projectTokenRate). Swaps are simple: reserve in → project out at that rate (or the reverse, depending on configuration).
• Invariant: The pool uses a constant-sum style invariant: projectBalance * projectTokenRate + reserveBalance, i.e. total value in terms of the reserve token. No weighted math or time-dependent weights.
• Buy-only (one-way): Fixed Price LBPs are configured so that only buying the project token with the reserve token is allowed. Selling the project token back into the pool is disabled.
• Seedless: Because the sale is one-way, the pool is initialized with project tokens only. No reserve tokens are required up front; buyers supply the reserve token when they swap.

# Summary