Blockchain APIs

Blockchain and cryptocurrency APIs

11 APIs in this category
Showing 11 of 11 APIs

Bitquery

Onchain GraphQL APIs & DEX APIs for blockchain data analysis

Auth: apiKey HTTPS CORS: Yes

Chainlink

Build hybrid smart contracts with decentralized oracle networks

Auth: No HTTPS CORS: Unknown

Chainpoint

Global network for anchoring data to the Bitcoin blockchain

Auth: No HTTPS CORS: Unknown

Covalent

Unified API for multi-blockchain data aggregation and analytics

Auth: apiKey HTTPS CORS: Unknown

Etherscan

Ethereum blockchain explorer API for transactions and smart contracts

Auth: apiKey HTTPS CORS: Yes

Helium

Access data from the global decentralized wireless network Helium

Auth: No HTTPS CORS: Unknown

Nownodes

Blockchain-as-a-service API providing access to full nodes and block explorers

Auth: apiKey HTTPS CORS: Unknown

Steem

Blockchain-based social media and blogging platform

Auth: No HTTPS CORS: No

The Graph

Decentralized indexing protocol for querying blockchain data via GraphQL

Auth: apiKey HTTPS CORS: Unknown

Walltime

Retrieve market information and trading data from Walltime

Auth: No HTTPS CORS: Unknown

Watchdata

Reliable API access to Ethereum and other blockchain networks

Auth: apiKey HTTPS CORS: Unknown

Best Blockchain APIs for Developers

A blockchain API allows developers to read on-chain data, broadcast transactions, query smart contracts, and interact with decentralized networks without running a full node. These APIs abstract away the complexity of peer-to-peer blockchain protocols.

CodeHelper's curated blockchain API collection includes APIs covering Bitcoin, Ethereum, NFTs, DeFi protocols, and multi-chain data aggregators.

What to look for in a blockchain API

  • Chain support: Ensure the API supports all the networks your dApp targets, such as Ethereum, Polygon, or Solana.
  • Websocket support: Real-time subscriptions to new blocks and events are essential for live dashboards.
  • Archive node access: For querying historical state, you need an API backed by an archive node, not just a full node.

How to use this API directory

  1. Browse the curated list of APIs below.
  2. Click any API to visit its documentation.
  3. Check the Auth column to understand what credentials you need.

Whether you are building a DeFi dashboard or an NFT marketplace, this free curated API directory saves you hours of research.

Related

apiCryptocurrency APIsCryptocurrency data and tradingtoolXML FormatterProfessional XML formatter with syntax highlighting, statistics, XML to JSON conversion, and XPath query tester.toolBase64 Encoder/DecoderEncode and decode Base64 strings, files, images with data URL support. Upload files or paste text for instant conversion.