ClearTrace
Blockchain
Cross-frontend DEX attribution and execution quality data across Ethereum and L2s
No keyCORSHTTPS
Free Blockchain APIs
Free public APIs for blockchain, each one verified and kept up to date.
15 listed · 8 need no key · 3 work in the browser
Helium
Blockchain
Helium is a global, distributed network of Hotspots that create public, long-range wireless coverage
No keyCORSHTTPS
Steem
Blockchain
Blockchain-based blogging and social media website
No keyCORS
Chainlink
Blockchain
Build hybrid smart contracts with Chainlink
No keyHTTPS
Chainpoint
Blockchain
Chainpoint is a global network for anchoring data to the Bitcoin blockchain
No keyHTTPS
Get Started with Web3
Blockchain
Bilingual Web3 lessons, glossary search and role-based learning paths
No keyHTTPS
TWZRD Agent Intel
Blockchain
Solana on-chain agent trust scoring via MCP; 4 free tools to score, resolve and verify AI agent wallets
No keyHTTPS
Walltime
Blockchain
To retrieve Walltime's market info
No keyHTTPS
Bitquery
Blockchain
Onchain GraphQL APIs & DEX APIs
API keyHTTPS
Blockscout
Blockchain
Multichain block explorer REST API (with Etherscan-compatible JSON-RPC)
API keyHTTPS
Covalent
Blockchain
Multi-blockchain data aggregator platform
API keyHTTPS
Etherscan
Blockchain
Ethereum explorer API
API keyHTTPS
Nownodes
Blockchain
Blockchain-as-a-service solution that provides high-quality connection via API
API keyHTTPS
The Graph
Blockchain
Indexing protocol for querying networks like Ethereum with GraphQL
API keyHTTPS
Watchdata
Blockchain
Provide simple and reliable API access to Ethereum blockchain
API keyHTTPS
All 15 Blockchain APIs
Free Blockchain APIs — common questions
Counts and timings below come from our own scheduled checks of this category.
How many free blockchain APIs are there?
We track 15 in this category, of which 13 responded at our last check. 8 of them need no API key.
Which blockchain APIs work without an API key?
8 of the 15 entries here need no credential. Filter this page by "no key" to see them, or browse the no-key collection for every keyless API across all categories.
Can I use these blockchain APIs in a browser app?
3 entries in this category need no key and return CORS headers, which is the combination that lets you call them straight from client-side JavaScript. The rest need a server or a proxy in between.
Which is the fastest free blockchain API?
Of the keyless options that responded at our last check, Steem was quickest at a median 473 ms. Speed is only one factor — coverage and licensing usually matter more — but it is measured here rather than claimed.
How do you know these APIs still work?
We call every listing on a schedule and record the status code, response time and whether CORS headers came back. Those results drive the badges on this page. Across the whole catalogue, 487 of 2,712 entries were not responding at the last full run, which is the sort of thing an unchecked list never tells you.