What is a genesis block?
- Author
- CRYPTO PORT Editorial
- Published
- Updated
- Reading time
- 4 min
In short
The genesis block is the first block of a blockchain — the starting point with no prior history behind it. Initial balances and configuration values are written straight into it, so it is where you can check who was allocated what at launch. It is a genuinely useful place to look when you want to know what a network really is.
Key points
- The first block, with no predecessor
- Initial balances and network parameters are written into it
- Nodes identify a chain by matching this block
- It shows who received what at launch
Definition
The first block in a blockchain — the only one that references no previous block — which defines the network's initial state, including starting balances and parameters.
A blockchain forms a single chain because each block contains the hash of the one before it. The very first block has nothing to point back to, so it exists as a fixed value written directly into the software. That is the genesis block.
On most networks, the initial distribution is recorded there. The state the network started in — which addresses held how much — is preserved in the chain itself, which makes it a way to check a project's published allocation against what actually happened.
When a node starts up it compares its genesis block with its peers', and treats a mismatch as a different network entirely. That check is why testnets and private chains never merge with production. Bitcoin's genesis block famously carries a newspaper headline from the day it was created.
Watch out for
- · If the on-chain allocation differs from the published figures, ask why
- · The reward in Bitcoin's genesis block is unspendable by design
- · Newer chains set their own initial state, so lopsided allocations are common