What is Bitcoin Core and what is it used for?

Bitcoin Core is the open source software that most people mean when they talk about running a full Bitcoin node. It downloads and checks every block on the network itself, and it also includes a Bitcoin wallet. The project describes it as a direct descendant of the first Bitcoin client released by Satoshi Nakamoto.

What is Bitcoin Core used for?

Its main job is to run a full node. A node keeps its own copy of the blockchain and checks every block and transaction against Bitcoin's rules, instead of trusting someone else's server. Node operators use Bitcoin Core to verify their own payments, relay transactions to other nodes and, for miners, build block templates. Our guide on how to run a Bitcoin node covers the setup.

The software is maintained by a large open source community. Contributors write code, review it, test it, document it and translate it, and maintainers with commit access merge approved changes. The project also maintains libsecp256k1, a cryptography library, and other related software.

What is the Bitcoin Core wallet?

Bitcoin Core comes with a built-in wallet that you can use through a desktop app (bitcoin-qt) or through commands. Because it runs on your own full node, the wallet checks your balance and transactions against your own copy of the blockchain. Since version 30, only descriptor wallets are supported. Older Berkeley DB (legacy) wallets can no longer be created or loaded and must be moved over with the migratewallet command. If you are new to wallets, see what is a crypto wallet.

What is Bitcoin Core v30?

Bitcoin Core 30.0 was released on October 10, 2025. Key changes in its release notes:

• OP_RETURN data. The default datacarriersize rose to 100,000, which in effect removes the old cap, and transactions with more than one OP_RETURN output can now be relayed and mined.
• Lower fees. The default minimum relay feerate dropped to 0.1 sat/vB.
• New bitcoin command. A single wrapper, such as bitcoin node or bitcoin gui, launches the other programs.
• Mining interface. An experimental interface lets mining software such as Stratum v2 tools request block templates.
• Desktop app. The GUI moved to Qt 6 and added dark mode on Windows.

The project aims for a major release every six months or so and maintains the latest three major versions. As of October 2026, the newest is version 31, released on April 19, 2026, which raised the default database cache and redesigned the mempool. Versions 30 and 29 are still maintained.

What is the difference between Bitcoin Core and Bitcoin Knots?

Both are node software for the same Bitcoin network, but Bitcoin Knots is a separate client with its own default settings. The OP_RETURN change in version 30 drew debate about how much non-payment data nodes should relay, and our guide to Bitcoin Knots explains that debate and how the two compare.