Update
Airnode Explained: Bringing Web APIs to Web3
Airnode is a Web 3.0 oracle solution that serves as a middleware to let blockchain-based smart contracts link to web APIs. It provides an open-source Web3 API middleware for any Web API to connect to blockchain-based decentralized applications (dApps). The service acts as a bridge for on-chain applications on the blockchain to access and interact with off-chain, real-world data provided by Web APIs. Unlike third-party oracle services, Airnode is free and open-source, charging no exorbitant fees.