Yes, there are several free APIs available for interacting with Bitcoin and other cryptocurrencies. Here are a few popular options:

1. CoinGecko API: CoinGecko offers a comprehensive cryptocurrency API that provides access to a wide range of data including prices, market cap, trading volume, and more for Bitcoin and thousands of other cryptocurrencies.

2. CoinAPI: CoinAPI provides a unified API interface for accessing real-time and historical cryptocurrency market data from various exchanges. They offer a free tier with limited access.

3. CoinDesk API: CoinDesk provides an API that offers access to Bitcoin price data, news, and other information related to the cryptocurrency market.

4. CryptoCompare API: CryptoCompare offers a free API that provides access to cryptocurrency prices, historical data, and other market information for Bitcoin and other cryptocurrencies.

5. Nomics API: Nomics offers a free cryptocurrency API that provides access to real-time and historical market data, including prices, trading volume, and market cap for Bitcoin and other cryptocurrencies.

These APIs typically offer both free and paid tiers with varying levels of access and features. It's essential to review their documentation and terms of service to understand the limitations and pricing structures before integrating them into your application.

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