> For the complete documentation index, see [llms.txt](https://functional.gitbook.io/database_comparison_report/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://functional.gitbook.io/database_comparison_report/blockchain/what-is-blockchain-technology.md).

# What is Blockchain technology?

A blockchain is a type of database, by and large distributed (although not necessarily). "Blockchain" is often used as a catchall term for a database that either is decentralized or that applies a proof of work, but this usage strays a bit from the true definition.

Essentially, a blockchain is a ledger of sequential transactions that are permanently saved and maintained in different locations.

<figure><img src="/files/Vf85xVEJrRZ13sUJHzfW" alt=""><figcaption></figcaption></figure>

The "genesis block" is the first bit of information on a blockchain, recording the starting state of all participants. From then on, all transactions are recorded in "blocks." These are chunks of transactions that have been processed at the same time and chained together.

The distinguishing feature of blockchain is this: no single person or organization is responsible for it. Instead, everyone in the same blockchain "ecosystem" keeps track of the transactions simultaneously.

Blockchain technology was originally invented to enable the Bitcoin cryptocurrency. The Bitcoin blockchain keeps track of who owns bitcoin and how much they own.

Every time an amount of Bitcoin is exchanged between two entities, the blockchain must come to a consensus about whether the transaction is legitimate. The transaction is then written to the blockchain, and the relevant account balances are updated.

Importantly, blockchains prevent people from making fraudulent transactions that would seriously harm the system. With so many people maintaining their own copy of the ledger, inserting a fake transaction into the blockchain is almost impossible.