How to: Blockchain
| API | Description | Auth | HTTPS | CORS |
|---|:---|:---|:---|:---|
| [Bitquery](https://graphql.bitquery.io/ide) | Onchain GraphQL APIs & DEX APIs | `apiKey` | Yes | Yes |
| [Chainlink](https://chain.link/developer-resources) | Build hybrid smart contracts with Chainlink | No | Yes | Unknown |
| [Chainpoint](https://tierion.com/chainpoint/) | Chainpoint is a global network for anchoring data to the Bitcoin blockchain | No | Yes | Unknown |
| [Covalent](https://www.covalenthq.com/docs/api/) | Multi-blockchain data aggregator platform | `apiKey` | Yes | Unknown |
| [Etherscan](https://etherscan.io/apis) | Ethereum explorer API | `apiKey` | Yes | Yes |
| [Helium](https://docs.helium.com/api/blockchain/introduction/) | Helium is a global, distributed network of Hotspots that create public, long-range wireless coverage | No | Yes | Unknown |
| [Nownodes](https://nownodes.io/) | Blockchain-as-a-service solution that provides high-quality connection via API | `apiKey` | Yes | Unknown |
| [Steem](https://developers.steem.io/) | Blockchain-based blogging and social media website | No | No | No |
| [The Graph](https://thegraph.com) | Indexing protocol for querying networks like Ethereum with GraphQL | `apiKey` | Yes | Unknown |
| [Walltime](https://walltime.info/api.html) | To retrieve Walltime's market info | No | Yes | Unknown |
| [Watchdata](https://docs.watchdata.io) | Provide simple and reliable API access to Ethereum blockchain | `apiKey` | Yes | Unknown |

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