The SparkSwap API is a set of endpoints used by market aggregators (e.g. coinmarketcap.com) to surface SparkSwap liquidity and volume information. All information is fetched from the underlying subgraphs.
Subgraph: https://api.thegraph.com/subgraphs/name/aldrickb/sparkswapgraphv2
The documentation of the endpoints can be found here.