Helium
HTTPS CORS ? Free
Helium is a global, distributed network of Hotspots that create public, long-range wireless coverage
API Endpoint
https://docs.helium.com/api/blockchain/introduction/More Blockchain APIs
Onchain GraphQL APIs & DEX APIs
HTTPS CORS apiKey
Build hybrid smart contracts with Chainlink
HTTPS CORS ? Free
Chainpoint is a global network for anchoring data to the Bitcoin blockchain
HTTPS CORS ? Free