Blockchain APIs provide access to cryptocurrency data, smart contracts, and decentralized networks. Query transaction histories, wallet balances, and real-time market data for Bitcoin, Ethereum, and thousands of altcoins.
Last verified: April 1, 2026
| Name | Description | Auth | HTTPS | CORS | Status |
|---|---|---|---|---|---|
| Bitquery | Onchain GraphQL APIs & DEX APIs | apikey | Yes | yes | alive |
| Chainlink | Build hybrid smart contracts with Chainlink | none | Yes | unknown | alive |
| Chainpoint | Chainpoint is a global network for anchoring data to the Bitcoin blockchain | none | Yes | unknown | alive |
| Covalent | Multi-blockchain data aggregator platform | apikey | Yes | unknown | dead |
| Etherscan | Ethereum explorer API | apikey | Yes | yes | alive |
| Helium | Helium is a global, distributed network of Hotspots that create public, long-range wireless coverage | none | Yes | unknown | alive |
| Nownodes | Blockchain-as-a-service solution that provides high-quality connection via API | apikey | Yes | unknown | alive |
| Steem | Blockchain-based blogging and social media website | none | No | no | alive |
| The Graph | Indexing protocol for querying networks like Ethereum with GraphQL | apikey | Yes | unknown | alive |
| Walltime | To retrieve Walltime's market info | none | Yes | unknown | dead |
| Watchdata | Provide simple and reliable API access to Ethereum blockchain | apikey | Yes | unknown | alive |
5 of these APIs require no authentication — you can start making requests immediately without signing up for an account. Just pick one from the table above, check its documentation, and send your first request.
6 APIs in this category require a free API key. This usually means creating a free account on the provider's website and copying your key from the dashboard. The process typically takes less than a minute.
Not sure where to start? Look for APIs marked as "alive" in the status column — these were recently verified as working. For browser-based projects, check that the API supports CORS.
Yes, all APIs listed on API Bouncer have a free tier. Some are completely open (no sign-up needed), while others require a free account to get an API key. Free tiers typically have rate limits — check each API's documentation for specifics.
It depends on your needs. Consider: Do you need authentication or prefer no-auth? Does your project need CORS support for browser access? How many requests will you make? Start with a no-auth API to prototype quickly, then switch to a more feature-rich option if needed.
We run periodic health checks on all listed APIs. The "Status" column shows whether each API was responding at our last check. APIs marked as "alive" were recently verified. You can also test any API yourself using curl or our guides on testing APIs.
Most free APIs allow commercial use, but terms vary by provider. Always check the specific API's terms of service. Some APIs have separate free and commercial tiers with different rate limits.
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