Smart Contract Security: 54 Checks Before Deploying to Mainnet

Smart contract bugs have caused billions of dollars in losses. Unlike traditional software, smart contracts are immutable once deployed — you cannot patch a vulnerability after the fact. A single mistake can be catastrophic.

Why Audit Your Own Contract First

Even if you plan to hire a professional auditor, a self-audit is essential. It helps catch obvious bugs before paying for a professional audit, reduces audit costs, and helps you understand your own code better.

The 10 Critical Security Categories

**1. Reentrancy** — The most common attack vector. Always update state before external calls.

**2. Access Control** — Who can call admin functions? Use OpenZeppelin AccessControl.

**3. Integer Overflow/Underflow** — Use Solidity 0.8+ or SafeMath. Never assume arithmetic is safe.

**4. Business Logic** — Does the token transfer logic correctly update all balances?

**5. Token Standard Compliance** — Does your ERC-20/BEP-20 fully implement the standard?

**6. Gas Optimization** — Unbounded loops can make transactions fail with out-of-gas errors.

**7. Timestamp Dependency** — Never use block.timestamp for randomness. Miners can manipulate it.

**8. External Calls** — Always check return values from .call() and .send().

**9. Code Quality** — NatSpec comments, pinned compiler version, no deprecated functions.

**10. Pre-Deploy Requirements** — Testnet testing, multisig wallet, liquidity lock, emergency pause.

The Most Common Critical Vulnerabilities

**Reentrancy (Critical):** Without protection, an attacker can recursively call your contract before the first call completes, draining funds. Fix: use ReentrancyGuard or Checks-Effects-Interactions pattern.

**tx.origin Authorization (Critical):** Using tx.origin instead of msg.sender allows phishing attacks. Always use msg.sender.

How to Use Our Checklist

Our Smart Contract Audit Checklist covers 54 security items across all 10 categories. For each item, mark Pass or Fail. The tool calculates your audit score and lets you export a full PDF report.

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