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Blobs and Dencun: How Ethereum Made Layer 2s 10x Cheaper

The Dencun upgrade introduced blob transactions that slashed L2 fees. Learn how proto-danksharding works.

The Problem Before Dencun

Layer 2 rollups post transaction data to Ethereum mainnet. Before Dencun, this data used expensive calldata, making L2 fees higher than necessary.

What Are Blobs?

Blobs (Binary Large Objects) are a new transaction type introduced by EIP-4844 (proto-danksharding). They provide a dedicated, cheaper data space on Ethereum specifically for rollup data.

How It Works

  • L2 rollups package transaction data into blobs
  • Blobs are attached to Ethereum transactions
  • Blobs are stored temporarily (~18 days) instead of permanently
  • A separate blob fee market keeps costs low and predictable

    • Impact on Fees

    After Dencun activated in March 2024:

    • Arbitrum fees: Dropped from ~$0.30 to ~$0.01

    • Optimism fees: Dropped from ~$0.25 to ~$0.005

    • Base fees: Dropped from ~$0.20 to ~$0.003

    • Scroll/zkSync fees: Similar dramatic reductions


    What is Next: Full Danksharding

    Proto-danksharding is step one. Full danksharding (planned for future upgrades) will increase blob capacity by 10-100x, potentially making L2 transactions nearly free.

    Impact on Alkizen Users

    Lower L2 fees mean cross-chain swaps through Alkizen are cheaper than ever. Swapping tokens on Base, Arbitrum, or Optimism now costs fractions of a cent in gas.

    dencunblobsEIP-4844layer 2