Spark is the DAI centric money market protocol. Combining the best liquidity directly from Maker and vertically integrating with the best DeFi protocols.
Spark Lend (SL) is a fork of Aave v3 with a Maker D3M (credit line) in the DAI market as supplier which means that the DAI market interest rate is constant & predictable, it is not based on the pool utilization and it is not dynamic. It can be only change based on the Dai Savings Rate defined by Maker Governance through an executive vote which you can find here.