Registering a tag

register() never submits anything on your behalf. It returns an unsigned transaction, and it is the connected wallet, not the SDK or the API, that signs and submits it. The user is the fee payer: they pay their own account rent (roughly 0.0018 SOL) and the network fee for this transaction, the same as any other Solana transaction they send.

const unsigned = await client.register({ tag: "daniel" });

// Hand unsigned.transaction to the connected wallet exactly as returned.
// signAndSendTransaction() is an optional convenience for a signer that
// also exposes signTransaction (most wallet adapters do); the default
// path is always to let the wallet's own adapter take it from here.
const signature = await client.signAndSendTransaction(unsigned.transaction, signer);

unsigned.transaction is a base64-encoded wire transaction. unsigned.pda is the tag account's derived address, and unsigned.lastValidBlockHeight tells the wallet how long the blockhash it was built with stays valid.

Insufficient balance

If the connected wallet cannot cover rent plus fees, the API responds 402 Payment Required instead of returning a transaction, and the SDK surfaces this as InsufficientBalanceError, carrying the exact lamport amounts:

import { InsufficientBalanceError } from "@tagwise/tip-sdk";

try {
  await client.register({ tag: "daniel" });
} catch (error) {
  if (error instanceof InsufficientBalanceError) {
    // error.requiredLamports, error.currentLamports, error.shortfallLamports
    // are all bigint. Show the user exactly how much more SOL they need
    // rather than a generic "transaction failed".
  }
}

Surface the shortfall directly, rather than a generic failure message: the user almost always just needs to fund their wallet before trying again.