In the Ethereum network, BLOB is short for Binary Large Object. It is essentially a new, and cheaper way for the network to store data. Essentially, certain Ethereum transactions would attach large chunks of temporary data, approximately 128KB per blob, to the main block. This would make things crowded and expensive.
Blobs were introduced in March 2024 through a major Ethereum upgrade known as Dencun Upgrade, more specifically through something called EIP-4844, also known as Proto-Danksharding. The goal was to solve a massive problem: high gas fees for Layer 2 networks like Arbitrum, Optimism, and Base.
Before this upgrade, Layer 2 rollups had to post their batch of transaction data to the Ethereum main chain using something called “calldata.” That method worked, but it was expensive because the data stayed on the blockchain forever and competed with regular transactions for space and gas fees. Now, when a Layer 2 network processes thousands of transactions, it bundles them together and packages them into a blob.
The best part is that blobs are temporary. They linger on the Ethereum network for roughly 18 days. Once that’s done, the data vanishes. This approach prevents the blockchain from being swamped by an avalanche of perpetual data, while still allowing users ample opportunity to retrieve and verify the information.
Your completely free resource hub designed to boost your knowledge of cryptocurrencies
With less storage needed, the expenses also drop. This upgrade was a key step toward making Ethereum more scalable.
Imagine if every coffee purchase were stored on the main blockchain for eternity; the system would eventually collapse under its own weight. Blobs provide a “delete” button for data that isn’t needed long-term. By doing so, it allows Layer 2s to offer lightning-fast speeds and barely charge any fees while still providing Ethereum’s world-class security.
Think of it like a sidecar attached to a motorcycle. Before blobs, every bit of data had to squeeze into the “motorcycle,” the main block, which quickly became cramped and costly. Now, substantial data can reside in the sidecar, freeing up the primary seat for crucial transactions.