How to Verify a Smart Contract Before You Interact With It

MetaMask shows you a contract address and asks you to approve it to spend your USDC. You have no way to tell who deployed it, what it can actually do, or whether the code matches what the site claims. You click Approve because the interface looks legitimate. That's exactly the gap that contract verification is supposed to close.

When a contract is verified on Etherscan, the developer has published the original Solidity source code and proven it compiles to the bytecode deployed on-chain. Anyone can read exactly what the contract does — no coding knowledge required for the basics. When a contract isn't verified, you're looking at raw machine code that's effectively unreadable, and you have no idea what you're approving.

How to check verification on Etherscan

• 1.Go to etherscan.io (or bscscan.com for BSC, basescan.org for Base)
• 2.Paste the contract address in the search bar
• 3.Click the "Contract" tab on the contract page
• 4.A green checkmark and readable Solidity source code means it's verified
• 5.If you only see a wall of hex bytecode, it's unverified — treat it as a red flag

Verified contracts also show "Read Contract" and "Write Contract" tabs, which let you query the contract state and simulate interactions directly in your browser.

What to actually look for in the source code

You don't need to be a Solidity developer to spot dangerous functions. These are the patterns worth searching for:

• —mint() or _mint() with no access control — anyone or the owner can create new tokens infinitely
• —setTax() or updateFee() — tax rates that can be changed after you buy
• —blacklist() or blockWallet() — functions that can prevent specific addresses from selling
• —transferOwnership() without a timelock — ownership can be transferred to a new malicious address
• —Upgradeable proxy patterns (look for delegatecall) — the contract logic can be swapped out entirely

Most of these are legitimate in some contexts. The question is whether they have appropriate access controls and whether you trust the entity that controls them.

Faster tools for contract checks

GoPlus Security API — automated analysis that flags hidden mint functions, sell restrictions, blacklist capabilities, and whether the contract is verified. Used by major aggregators. The fastest way to get a risk summary.

Token Sniffer — good for newly launched tokens. Runs a quick audit and assigns a score. Not a substitute for reading the code, but useful for filtering obvious scams.

Dedaub Contract Library — decompiles unverified contracts into pseudo-code. Not perfectly readable, but often good enough to spot obvious drainer functions.

Frequently asked questions