OneSource is blockchain data infrastructure for developers and AI agents. Our self-serve API delivers live Ethereum data - balances, transactions, events, contracts, ENS, and fully-resolved NFT metadata - via REST and a hosted MCP server, with a single API key and no nodes to run. Our white-glove Flex service builds custom indexed datasets and bespoke GraphQL APIs across any chain and any on- or off-chain source. Integrate once; skip the node ops and indexing pipelines.