Documentation Index Fetch the complete documentation index at: https://docs.blend.money/llms.txt
Use this file to discover all available pages before exploring further.
The frontend SDK (@blend-money/fe) handles wallet authentication, deposit/withdrawal quoting, and on-chain execution in the browser.
Quick-start flow
Install @blend-money/fe and viem
Create a BlendSdk instance with your publishable key and paymaster
Sign in with sdk.signIn()
Quote with sdk.quoteDeposit() or sdk.quoteWithdraw()
Execute with sdk.execute(quote, { deriveSigner })
Install pnpm add @blend-money/fe viem
npm install @blend-money/fe viem
yarn add @blend-money/fe viem
pnpm add @blend-money/node
npm install @blend-money/node
yarn add @blend-money/node
Configuration import { BlendSdk, getPimlicoPaymasterUrl } from "@blend-money/fe" ; const sdk = new BlendSdk ({ publishableKey: "pk_live_abc123..." , signMessage : ( msg ) => walletClient. signMessage ({ message: msg }), paymasterUrl: getPimlicoPaymasterUrl ( "pimlico_api_key_here" ), });
Field Type Required Description publishableKeystringYes Client-safe key (pk_live_). Identifies your organization and account type. signMessage(message: string) => Promise<string>For auth Wallet signing function for SIWE. Not needed for read-only usage. paymasterUrlPaymasterUrlResolverYes (chainId: number) => string. Returns the ERC-4337 paymaster RPC URL.baseUrlstringNo Blend API base URL. Defaults to production. fiatCurrencystringNo ISO 4217 code (e.g. "EUR"). Adds this currency to monetary responses. timeoutMsnumberNo Request timeout in milliseconds. Default: 15000. retriesnumberNo Max retries for 429 and 5xx. Default: 3.
Authentication signIn Signs the user in with SIWE. Creates the account and Safe if this is their first time.
const session = await sdk. signIn ({ address: "0x1234...abcd" , chainId: 8453 , });
Returns an AuthSession:
Field Type Description addressstringAuthenticated wallet address accountIdstringBlend account ID safeAddressstringOn-chain Safe address chainsDeployednumber[]Chains where the Safe is live expiresAtstringISO 8601 expiry (1 hour)
signOut Revokes the JWT server-side and clears local state.
isSignedIn Read-only boolean. true if a session is active.
if (sdk.isSignedIn) { // authenticated }
session Returns the current AuthSession. Throws SdkError with code AUTH_NOT_SIGNED_IN if not authenticated.
const { accountId , safeAddress } = sdk.session;
exportSession / restoreSession Persist and restore sessions across page reloads.
// Save before unload const snapshot = sdk. exportSession (); sessionStorage. setItem ( "blend" , JSON . stringify (snapshot)); // Restore on next load const saved = JSON . parse (sessionStorage. getItem ( "blend" ) ! ); sdk. restoreSession (saved);
Use sessionStorage, not localStorage. Clear the session when the wallet disconnects or the address changes.
Quoting quoteDeposit Quotes a deposit. Creates a session automatically if one doesn’t exist.
import { parseAmount } from "@blend-money/fe" ; const quote = await sdk. quoteDeposit ({ chainId: 8453 , tokenAddress: "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913" , amount: parseAmount ( "100" , 6 ), externalRef: "order-123" , });
Parameter Type Required Description chainIdnumberYes Origin chain ID tokenAddressstringYes Token contract on the origin chain amountstringYes Smallest unit, non-negative integer string externalRefstringNo Your reconciliation reference forceResetbooleanNo Cancel existing session first. Default: false.
Returns a DepositQuote:
Field Type Description type"DEPOSIT"Quote type intentIdstringSession ID originChainIdnumberChain the user sends from destinationChainIdnumberChain where funds arrive inputobjectsymbol, amount, amountUsd the user sendsoutputobjectsymbol, amount, amountUsd arriving in the vaultfees.totalUsdstringTotal fees in USD estimatedSecondsnumberEstimated settlement time expiresAtstringWhen this quote expires
quoteWithdraw Quotes a withdrawal. Blend picks which chains to pull funds from.
const quote = await sdk. quoteWithdraw ({ destinationChainId: 8453 , amount: parseAmount ( "50" , 6 ), });
For a full exit, set isMaxWithdraw: true and amount: "0":
const quote = await sdk. quoteWithdraw ({ destinationChainId: 8453 , amount: "0" , isMaxWithdraw: true , });
Returns a WithdrawQuote:
Field Type Description type"WITHDRAW"Quote type intentIdstringSession ID destinationChainIdnumberChain where funds arrive totalAmountstringTotal withdrawal in loan token smallest units totalFeesUsdstringTotal fees in USD estimatedSecondsnumberEstimated settlement time sourceChainCountnumberNumber of source chains sourceChainIdsnumber[]Which chains funds are pulled from expiresAtstringWhen this quote expires
Execution execute Locks the quote, submits transactions through the user’s Safe, and polls until settlement.
const result = await sdk. execute (quote, { signerAddress: "0x1234...abcd" , deriveSigner : async ( chainId ) => ({ signer: getWalletClient ({ chainId }), publicClient: getPublicClient ({ chainId }), }), onStatusChange : ( status ) => console. log (status), });
Parameter Type Required Description signerAddressstringYes EOA hex address. Must match the deriveSigner output. deriveSigner(chainId: number) => Promise<DeriveSignerResult>Yes Returns a viem WalletClient and PublicClient for the target chain isContractSignerbooleanNo Set true for smart wallets (e.g. Coinbase). Default: false. onStatusChange(status: ExecuteStatus) => voidNo Called on each status transition pollIntervalMsnumberNo Polling interval. Default: 3000. pollTimeoutMsnumberNo Max polling time. Default: 300000 (5 min).
deriveSigner is called once per action plan. For deposits, that means once. For withdrawals, once per source chain.DeriveSignerResult:Field Type Description signerWalletClientviem WalletClient for the target chain publicClientPublicClientviem PublicClient for the target chain
ExecuteResult:Field Type Description status"settled" | "failed" | "cancelled"Terminal status txHashesArray<{ hash: string; chainId: number }>Submitted transaction hashes settledAtstring | nullISO 8601 settlement time errorstring | nullError message if failed
Discovery These methods are available on sdk.discover. Deposit chains work without auth. Deposit tokens include wallet balances when signed in.
const chains = await sdk.discover. depositChains (); const tokens = await sdk.discover. depositTokens ( 8453 ); const destinations = await sdk.discover. withdrawDestinations (); const yieldData = await sdk.discover. yield ();
See SDK Reference for response shapes.
Account data These methods are available on sdk.account after sign-in.
const balance = await sdk.account. balance (); const history = await sdk.account. balanceHistory (); const positions = await sdk.account. positions (); const returns = await sdk.account. returns ();
See SDK Reference for response shapes.
Error handling Every SDK method can throw SdkError. Catch it to get structured error info.
import { SdkError } from "@blend-money/fe" ; try { const quote = await sdk. quoteDeposit ({ /* ... */ }); } catch (error) { if (error instanceof SdkError ) { console. error (error.code); // "INTENT_EXPIRED" console. error (error.status); // 410 console. error (error. getUserMessage ()); // user-friendly text if (error. isRetryable ()) { /* retry */ } } }
See SDK Reference for the full error codes table.
What to watch out for Don’t create a new session to update prices. Call quoteDeposit() again on the open session. It re-quotes with fresh prices. Use forceReset: true only when switching tokens or chains.Don’t store sessions in localStorage. Use sessionStorage and clear it when the wallet disconnects.Don’t skip the onStatusChange callback. Show status updates in your UI so users know what’s happening during execution.Don’t ignore isContractSigner. If your users connect smart wallets (Coinbase Wallet, Safe), set it to true or signing will fail.
Deposits & Withdrawals Full deposit and withdrawal flows with cross-chain routing.
SDK Reference Auth, accounts, balances, error codes, and types.
