Custom ERC20 Token — Gas-Optimized Implementation

This project contains two ERC20 token implementations:

• Token.sol — A custom, lightweight, gas-optimized ERC20 written in Solidity + Yul.
• Token2.sol — A standard implementation extending OpenZeppelin ERC20.

The purpose of this repository is to compare performance and gas efficiency between a hand-optimized ERC20 implementation and the official OZ version.

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Overview

This project demonstrates how a manually optimized ERC20 implementation can outperform OpenZeppelin’s ERC20 in:

• Deployment cost
• Mint/burn costs
• Approvals and allowances
• General state-changing operations

…while maintaining full ERC20 compliance.

This repository includes:

• ✔ Source contracts
• ✔ Foundry test suite
• ✔ Mainnet-fork & Sepolia gas reports
• ✔ Deep efficiency comparison

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Gas Report Summary

Gas reports were generated on:

• Local Foundry test environment
• Ethereum Mainnet fork
• Sepolia testnet fork

Results remained consistent across networks.

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Mainnet Fork Gas Report

Token.sol (Custom ERC20)

Deployment

Metric	Value
Deployment Gas	711,427
Deployment Size	3728 bytes

Function Costs

Function	Min	Avg	Median	Max	Calls
allowance	3312	3312	3312	3312	4
approve	22052	40613	46801	46801	4
balanceOf	2720	2720	2720	2720	11
burn	22145	24078	24078	26012	2
decimals	427	427	427	427	1
mint	22079	61695	66648	66648	9
name	3330	3330	3330	3330	1
symbol	3373	3373	3373	3373	1
totalSupply	2317	2317	2317	2317	3
transfer	22190	33649	26852	51906	3
transferFrom	25284	39104	39104	52924	2

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Token2.sol (OpenZeppelin ERC20)

Deployment

Metric	Value
Deployment Gas	955,366
Deployment Size	4870 bytes

Function Costs

Function	Min	Avg	Median	Max	Calls
allowance	3245	3245	3245	3245	4
approve	22356	40794	46940	46940	4
balanceOf	2850	2850	2850	2850	11
burn	22374	25081	25081	27788	2
decimals	427	427	427	427	1
mint	22308	63754	68935	68935	9
name	3330	3330	3330	3330	1
symbol	3373	3373	3373	3373	1
totalSupply	2477	2477	2477	2477	3
transfer	22478	33297	25204	52211	3
transferFrom	25799	39712	39712	53626	2

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Sepolia Fork Gas Report

Token.sol (Custom ERC20)

Same results as mainnet fork (expected).

Function	Min	Avg	Median	Max	Calls
allowance	3312	3312	3312	3312	4
approve	22052	40613	46801	46801	4
balanceOf	2720	2720	2720	2720	11
burn	22145	24078	24078	26012	2
decimals	427	427	427	427	1
mint	22079	61695	66648	66648	9
name	3330	3330	3330	3330	1
symbol	3373	3373	3373	3373	1
totalSupply	2317	2317	2317	2317	3
transfer	22190	33649	26852	51906	3
transferFrom	25284	39104	39104	52924	2

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Token2.sol (OpenZeppelin ERC20)

Function	Min	Avg	Median	Max	Calls
allowance	3245	3245	3245	3245	4
approve	22356	40794	46940	46940	4
balanceOf	2850	2850	2850	2850	11
burn	22374	25081	25081	27788	2
decimals	427	427	427	427	1
mint	22308	63754	68935	68935	9
name	3330	3330	3330	3330	1
symbol	3373	3373	3373	3373	1
totalSupply	2477	2477	2477	2477	3
transfer	22478	33297	25204	52211	3
transferFrom	25799	39712	39712	53626	2

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Testing

Install dependencies

forge install

Run tests

forge test

Generate gas reports

forge test --gas-report

Run on mainnet fork

forge test --fork-url $MAINNET_RPC --gas-report

Run on Sepolia fork

forge test --fork-url $SEPOLIA_RPC --gas-report

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Project Structure

contracts/
 ├── ERC20.sol
 ├── IERC20.sol
 ├── helpers/
 │     ├── IERC20Errors.sol
 │     └── ERC20Internals.sol
test/
 ├── Token.sol
 ├── Token2.sol
 ├── Token.t.sol
 └── Token2.t.sol
README.md
foundry.toml

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License

MIT License — free for use and modification.

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Contributions

Pull requests and improvements are welcome.