Most of the time you interact with a smart contract through an app. You open a swap interface, pick a token, and click a button. The app builds the transaction for you and your wallet asks you to confirm it. That is the normal path, and for most people it is the only path they ever need.
But every verified contract on Basescan also exposes two tabs, Read Contract and Write Contract, that let you skip the app entirely and talk to the contract directly. This is not a hidden feature. It is a standard part of any block explorer built on the same tooling as Etherscan, and it is worth understanding even if you rarely use it yourself, because it explains a lot about how tokens and dapps actually work under the hood.
What "verified" has to do with it
A smart contract on Base is just compiled bytecode sitting at an address. On its own, that bytecode is unreadable. When a developer verifies a contract, they upload the original source code and Basescan checks that it compiles to the exact bytecode deployed on-chain. Once that match is confirmed, Basescan can map the contract's function names and inputs to something you can actually read and use, instead of a wall of hex.
Read and Write Contract only show up in a useful form on verified contracts. An unverified contract can still be used from an app that already knows its interface, but Basescan cannot generate a readable form for it because it doesn't know what the functions are called or what they expect.
The Read tab
The Read tab lists every "view" or "pure" function on the contract, the kind that looks something up without changing anything. Calling one of these costs nothing and needs no wallet connection, because you are not sending a transaction. You are just asking the contract a question and it answers immediately in your browser.
Typical things you can check here:
- A token's
totalSupply, or itsbalanceOffor a specific address - Whether an address has been granted a role, like being an owner or a minter
- The current exchange rate or price stored inside a vault or pool contract
- How much of an allowance one address has approved for another to spend
This is genuinely useful outside of any app. If someone tells you a token has a certain supply or that a contract is owned by a particular address, you can check the Read tab yourself instead of taking their word for it.
The Write tab
The Write tab lists the functions that do change something on-chain, like transferring tokens, approving a spender, or calling a contract's own admin functions. To use one, you connect a wallet directly on the Basescan page, the same way you would connect it to any dapp. Fill in the function's parameters, click the button, and your wallet pops up asking you to confirm a transaction, exactly as it would from an app.
This is a real transaction with real gas, sent from your own wallet. Basescan is not a special trusted intermediary here, it is just building the transaction data for you based on the contract's interface and handing it to your wallet to sign.
People reach for this when there is no app for what they need to do. That comes up with older or niche contracts, with claiming from a specific vesting or airdrop contract that never got a frontend, or with calling a function on a token you already hold that isn't exposed anywhere else. It is a fallback for when the interface you'd normally use doesn't exist, not a replacement for it.
Why this matters even if you never use it
Understanding that Read and Write are just a translated view of the contract's functions makes a few other things click. It's the same reason a "verified" badge is a transparency signal and not a safety guarantee, since verification tells you the source code matches what's deployed, not that the code is safe or well designed. It's also why apps and block explorers can both interact with the exact same contract and get identical results: they are calling the same functions underneath, just through different interfaces.
It also explains why a scam token can still show a plausible totalSupply or balanceOf on the Read tab. The contract is doing exactly what its code says, and if that code was written to mislead, an honest-looking read function does not make the token safe. The Read tab tells you what the contract reports, not whether the contract deserves your trust.
A few practical notes
If you do use the Write tab, treat it with the same caution as any other transaction. Your wallet's confirmation screen is the last checkpoint, so read what it says you're approving before you sign. Double check you're on the real Basescan domain, since a fake copy of the site could present a convincing-looking Write tab that sends your funds somewhere you didn't intend. And if a function takes an address as a parameter, paste it carefully. Basescan will not stop you from calling a function with the wrong input.
For most day to day use, an app will always be the simpler path. But knowing that Read and Write Contract exist, and what they actually do, is a useful piece of how Base and contracts on it really work.