Coinbase transaction

In plain words

The first transaction in every block is the miner paying itself. It has no sender — the coins appear by rule, from nowhere — and it collects the block's new bitcoin plus every fee. This is the only birthplace of bitcoin. Miners may tuck a short message inside; that is how the first block carries its newspaper headline. The reward stays locked for 100 blocks.

Why it matters

• Every coin in existence traces back to some block's coinbase.
• The 100-block wait guards against paying out blocks later replaced.
• Its text field is Bitcoin's guestbook: headlines, prayers, pool tags.

Not to be confused with

• Coinbase (the company) — an exchange that borrowed the name. No relation.

Go deeper

• Block reward
• The genesis block
• Orphan & stale blocks