Choosing a Bitcoin API depends on what you're building. This guide compares the major options so you can pick the right one for your project.
Not all Bitcoin APIs are the same. Before choosing, consider these criteria:
An honest look at each option — strengths, limitations, and ideal use cases.
The canonical interface to a Bitcoin node. Every other API ultimately depends on Bitcoin Core (or a compatible implementation) under the hood. The JSON-RPC interface gives you access to everything: raw transactions, block data, mempool contents, wallet operations, and network info.
Strengths: Complete access to node functionality. No third-party dependencies. The ground truth for Bitcoin data. Well-documented in the Bitcoin Core source.
Limitations: Responses are complex and unprocessed — you'll need to build your own analysis layer. No REST interface by default (JSON-RPC only). Requires running a full node (500+ GB disk). No address indexing without additional software (e.g., ElectrumX).
A popular open-source block explorer with a clean REST API. Excellent for mempool visualization, fee estimation, address lookups, and block data. The public instance at mempool.space is free to use and handles significant traffic.
Strengths: No setup required — just start making HTTP requests. Strong mempool and fee data. Beautiful block explorer UI. Open source and self-hostable. Active development and community.
Limitations: Public instance has rate limits (varies, generally generous for moderate use). Not designed for high-frequency programmatic access. Address lookups may be slow for addresses with thousands of transactions. No analyzed data beyond what the explorer shows.
A multi-chain SaaS API supporting Bitcoin, Ethereum, Litecoin, and Dash. Offers address endpoints, transaction broadcasting, webhooks/websockets, and confidence ratings. Has been around since 2014 and powers many production apps.
Strengths: Multi-chain support from a single API. Webhooks and websockets for real-time events. Transaction confidence ratings. Official Python, Ruby, and Node SDKs. Well-established with years of uptime.
Limitations: Free tier limited to 200 requests/hour and 2000/day. Paid plans start at $75/month and scale to $500+/month. Hosted only — you can't self-host. Privacy trade-off: all queries go through BlockCypher's servers.
One of the oldest Bitcoin APIs, tied to the Blockchain.com block explorer and wallet. Provides endpoints for blocks, transactions, addresses, and exchange rates. Simple to get started with.
Strengths: Simple API surface. Exchange rate data included. Long track record. No API key required for basic access.
Limitations: Rate limits are strict and not always clearly documented. Limited endpoint coverage compared to newer alternatives. The API has seen less active development in recent years. Hosted only.
An open-source block explorer and API built by Blockstream. Powers blockstream.info. Focuses on address lookups, UTXO queries, transaction data, and fee estimates. Designed to be self-hosted alongside a Bitcoin node and an Electrs indexer.
Strengths: Fully open source (MIT). Self-hostable for complete privacy. Clean REST API. Address and UTXO endpoints. Active maintenance by Blockstream. Public instance available at blockstream.info/api.
Limitations: Self-hosting requires running Electrs (additional indexing overhead). No analyzed/computed data — returns raw indexed data. No webhooks or streaming. Public instance has rate limits.
An open-source REST API layer that sits on top of your own Bitcoin Core node. Transforms raw RPC data into analyzed, developer-friendly endpoints. Includes fee analysis, mempool statistics, mining analytics, difficulty projections, and real-time SSE streams. Also ships an MCP server for AI agent integration.
Strengths: Self-hosted — your node, your data, no third parties. 75+ analyzed endpoints with computed metrics. Smart caching for performance. MCP server for AI agents (Claude, etc.). Installable via pip install satoshi-api. Apache-2.0 licensed. No rate limits on self-hosted instances.
Limitations: Requires running your own Bitcoin Core node. No address indexing (by design — focuses on network/mempool/mining data). Newer project with a smaller community than established alternatives. Single-chain (Bitcoin only).
Side-by-side feature comparison across all major Bitcoin APIs.
| Core RPC | Mempool.space | BlockCypher | Blockchain.com | Esplora | Satoshi API | |
|---|---|---|---|---|---|---|
| Hosting | Self-hosted | Hosted + self | Hosted only | Hosted only | Hosted + self | Self-hosted |
| Price | Free | Free | Free tier / $75+ | Free tier | Free | Free |
| Privacy | Full | Self-host only | No (SaaS) | No (SaaS) | Self-host only | Full |
| AI / MCP support | No | No | No | No | No | Yes (native) |
| Analyzed data | Raw only | Some | Some | Basic | Raw indexed | Yes (73 endpoints) |
| Address endpoints | No* | Yes | Yes | Yes | Yes | No |
| Real-time streams | ZMQ only | WebSocket | WebSocket | No | No | SSE |
| Open source | Yes | Yes | No | No | Yes | Yes (Apache-2.0) |
| Multi-chain | No | Liquid | Yes | Limited | Liquid | No |
| Python SDK / pip | Community libs | HTTP only | Official SDK | HTTP only | HTTP only | pip install |
* Bitcoin Core supports address lookups only with -txindex and wallet descriptors. No dedicated address API.
Quick recommendations based on what you're building.
Wallets need address lookups, UTXO queries, and transaction broadcasting. You need reliable address endpoints and ideally webhooks for payment notifications.
BlockCypher or Esplora
If your users' queries should never touch a third-party server, you need a self-hosted solution. Run your own node and API layer.
Satoshi API or Esplora (self-hosted)
AI agents need structured Bitcoin data through standardized tool protocols. MCP (Model Context Protocol) is the emerging standard for agent-to-API communication.
Satoshi API (native MCP server)
When you just need to query some Bitcoin data without any setup — no API keys, no node, no infrastructure.
Mempool.space (zero setup)
If your app needs Bitcoin, Ethereum, and Litecoin data from a single API provider with consistent interfaces.
BlockCypher
High-volume production apps hit rate limits fast on hosted APIs. Self-hosted options give you unlimited requests and no monthly bills.
Satoshi API (free, no rate limits)
There is no single "best" Bitcoin API — only the best one for your specific requirements. If you're just exploring, start with Mempool.space and see how far it takes you. If you're building something serious and care about privacy, independence, or AI integration, evaluate the self-hosted options.
The good news: most of these tools are free and open source. You can try several and switch with minimal code changes, since they all speak HTTP.