Blockchain – Free-tier APIs
16 Free-tier APIs in the category Blockchain. Free public web APIs that developers and AI agents can call. Entries come from the open public-apis list; each link was checked automatically (HTTP status) on the date shown, which says the site responded, not that the API is good.
Bitquery
Onchain GraphQL APIs & DEX APIs
Blockscout
Multichain block explorer REST API (with Etherscan-compatible JSON-RPC)
Chainlink
Build hybrid smart contracts with Chainlink
Chainpoint
Chainpoint is a global network for anchoring data to the Bitcoin blockchain
ClearTrace
Cross-frontend DEX attribution and execution quality data across Ethereum and L2s
Covalent
Multi-blockchain data aggregator platform
Dwellir
RPC endpoints for 150+ blockchain networks, including Ethereum, Solana, Polkadot and Hyperliquid
Etherscan
Ethereum explorer API
Get Started with Web3
Bilingual Web3 lessons, glossary search and role-based learning paths
Helium
Helium is a global, distributed network of Hotspots that create public, long-range wireless coverage
Nownodes
Blockchain-as-a-service solution that provides high-quality connection via API
Steem
Blockchain-based blogging and social media website
SwiftNodes
Multi-chain blockchain RPC nodes (Ethereum, Solana and 75+ networks)
The Graph
Indexing protocol for querying networks like Ethereum with GraphQL
TWZRD Agent Intel
Solana on-chain agent trust scoring via MCP; 4 free tools to score, resolve and verify AI agent wallets
Watchdata
Provide simple and reliable API access to Ethereum blockchain