Web3 Decentralization

Gas Optimization 101

· September 9, 2026

Back to: L2 Developer Path

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Objective: stop overpaying for computation — as a user today, as a builder tomorrow.

Every EVM operation has a price. Users optimize by *when* and *how* they transact; builders optimize by writing less work into contracts.

Concept: where gas actually goes

Storage writes dominate (20,000 gas per fresh slot vs 100 for arithmetic). Loops over unbounded arrays, redundant checks, and chatty cross-contract calls are the classic wasters. On L2s, data posting dominates instead — different bottleneck, same discipline.

Hands-on lab (free)

  1. Compare gas used by a simple transfer vs a swap vs an NFT mint on an explorer — feel the 10-100x spreads.
  2. Toggle a wallet’s fee settings (low/market/aggressive) on testnet; watch confirmation times differ.
  3. For builders: pack two uint256 into one slot pattern, or cache array length outside loops — measure the difference on a testnet deploy.

Safety checklist

  • Lowballing gas on time-sensitive DeFi exits (liquidations, claims) costs more than it saves.
  • “Gas tokens” and refund gimmicks are mostly dead — ignore them.
  • On L2s, watch the *data* component; blob congestion is the new fee spike.

Next lesson: reading L2Beat like an auditor.