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Build on Kaspa

What is Kaspa

Every blockchain has the same bottleneck. Blocks arrive in a line, one at a time, and the line has room for exactly one block at each position. When two miners find a block at the same moment, one of them is discarded — the work is real, the block is valid, and it is thrown away anyway.

That is why Bitcoin mines slowly. At ten minutes per block, two miners almost never collide, so almost nothing is wasted. Speed up the block rate and collisions become common; discard rate climbs, and with it the share of honest work that counts for nothing.

Keeping the blocks instead

Kaspa changes the shape of the structure rather than the speed of the miners. A block references several parents instead of one, so two blocks found at the same instant are both kept and later merged. Nothing is orphaned, so nothing is wasted, so the block rate is free to rise — Kaspa produces blocks about once per second.

The result is not a chain but a directed acyclic graph: a BlockDAG.

Click blocks to select parents, then add a block on that selection. Blocks with no children yet are tips.

Click a block to select it as a parent, then add a block on that selection. Try selecting an old block: that is a miner whose view of the network lagged. In a blockchain its work is wasted. Here the DAG absorbs it and later blocks merge it back in.

The problem this creates

A chain gets transaction order for free — the line is the order. A DAG does not. If two blocks are mined in parallel and both spend the same coin, nothing about the graph says which one came first, and every node has to reach the same answer independently or the ledger falls apart.

Kaspa’s answer is GHOSTDAG: a rule for finding the blocks that were mined by well-connected miners, and using them to put every block in one agreed order. That is the idea the rest of this section builds up to.

Where to go next