RainFi loan operations - Synto Mobile

The RainFi loan operations enable collateralized lending on Solana. Users can borrow assets against collateral with transparent terms, competitive APRs, and automated liquidation protection.

Quote loan calculator

Calculate loan quotes with optimal interest rates based on available liquidity pools.

Function signature

quoteLoanCalculator(params: {
  amountIn: number;
  currencyIn: string;
  currencyOut: string;
  borrower: string;
}): Promise<LoanTransactionRequest>

Parameters

amountIn

number

required

Amount of collateral to deposit, in smallest units (lamports for SOL)

currencyIn

string

required

Collateral currency address. Must be a valid Solana token mint address.Example: "So11111111111111111111111111111111111111112" for SOL

currencyOut

string

required

Loan currency address. Must be a valid Solana token mint address.Example: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v" for USDC

borrower

string

required

Borrower’s wallet public key as a base58 string

Response

LoanTransactionRequest

object

Complete loan request ready for execution

Show properties

borrower

string

Borrower’s wallet address

amountIn

number

Collateral amount in smallest units

currencyIn

string

Collateral currency address

currencyOut

string

Loan currency address

simulation

LoanSimulation

Best available loan terms from liquidity pools

Show simulation properties

amount

number

Loan amount in smallest units

duration

number

Loan duration in seconds

interest

string

Total interest amount as string

rainFees

number

RainFi protocol fees

apr

number

Annual percentage rate

authorization

string

Authorization token for transaction execution

bank

string

Bank account address

pool

string

Liquidity pool address

baseAmount

number

Base loan amount before fees

currency

string

Loan currency address

slippage

number

Slippage tolerance in basis points (default: 1000 = 10%)

options

TransactionOptions

Transaction fee configuration

Show options properties

prioritizationFeeLamports

string

Priority fee level: "fast", "medium", or "slow"

maxFeeCapLamports

number

Maximum fee cap in lamports (optional)

jitoTipLamports

number

Jito MEV tip amount in lamports (optional)

Example usage

import { quoteLoanCalculator } from '@/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools';

const quote = await quoteLoanCalculator({
  amountIn: 1000000000, // 1 SOL
  currencyIn: "So11111111111111111111111111111111111111112", // SOL
  currencyOut: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v", // USDC
  borrower: "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs",
});

console.log(`Loan amount: ${quote.simulation.amount}`);
console.log(`APR: ${quote.simulation.apr}%`);
console.log(`Duration: ${quote.simulation.duration} seconds`);

API endpoint

POST https://api-v3.rain.fi/loan-calculator/defi/quote

Request body
Response

{
  "order": ["LowestInterest"],
  "amountIn": 1000000000,
  "currencyIn": "So11111111111111111111111111111111111111112",
  "currencyOut": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
  "minDurationInDays": 1,
  "borrower": "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs"
}

{
  "order": ["LowestInterest"],
  "amountIn": 1000000000,
  "currencyIn": "So11111111111111111111111111111111111111112",
  "currencyOut": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
  "borrower": "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs",
  "isReverse": false,
  "minDurationInDays": 1,
  "simulations": [
    {
      "amount": 109821097,
      "duration": 691200,
      "interest": "0",
      "rainFees": 0,
      "apr": 0,
      "pool": "B4eiUfuTBjiy8BbcdU44PT7q57TkmK54dWtT3YJAZZTB",
      "bank": "6SaE8e2bpm78Ewv8WUqguEPYUoEXRNTn7jzL8xzgH6Bv",
      "authorization": "C6MnBHEVVRkoFkt6uzJzboYJU4vCZbkjC2EtsXk3GbRs"
    }
  ]
}

Build loan transaction

Build and execute a loan transaction using pre-calculated quote parameters.

Function signature

RainfiTransactionBuilder(
  agent: SolanaAgentKit,
  params: LoanTransactionRequest
): Promise<string>

Parameters

agent

SolanaAgentKit

required

Initialized Solana agent instance with wallet and connection

params

LoanTransactionRequest

required

Complete loan request from quoteLoanCalculator. See Quote loan calculator for field details.

Response

signature

string

Transaction signature after successful execution

Example usage

import { quoteLoanCalculator, RainfiTransactionBuilder } from '@/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools';
import { SolanaAgentKit } from '@/utils/syntoUtils/agent';

// Step 1: Get loan quote
const quote = await quoteLoanCalculator({
  amountIn: 1000000000,
  currencyIn: "So11111111111111111111111111111111111111112",
  currencyOut: "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
  borrower: agent.wallet.publicKey.toString(),
});

// Step 2: Display quote to user
console.log(`APR: ${quote.simulation.apr}%`);
console.log(`Loan amount: ${quote.simulation.amount}`);

// Step 3: Execute transaction
const signature = await RainfiTransactionBuilder(agent, quote);
console.log(`Transaction successful: ${signature}`);

API endpoint

POST https://api-v3.rain.fi/transaction-builder/defi/take-loan

Request body
Response

{
  "borrower": "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs",
  "amountIn": 23000000000,
  "currencyIn": "So11111111111111111111111111111111111111112",
  "currencyOut": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
  "simulation": {
    "amount": 109821097,
    "duration": 691200,
    "interest": "0",
    "rainFees": 0,
    "apr": 0,
    "currency": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "bank": "6SaE8e2bpm78Ewv8WUqguEPYUoEXRNTn7jzL8xzgH6Bv",
    "authorization": "C6MnBHEVVRkoFkt6uzJzboYJU4vCZbkjC2EtsXk3GbRs",
    "pool": "B4eiUfuTBjiy8BbcdU44PT7q57TkmK54dWtT3YJAZZTB",
    "baseAmount": 109821097
  },
  "slippage": 50,
  "options": {
    "prioritizationFeeLamports": "fast",
    "maxFeeCapLamports": 0,
    "jitoTipLamports": 1408925
  }
}

{
  "transactions": ["AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAHEb...base64..."],
  "version": 0,
  "kind": "defi-take-loan",
  "blockhash": "4sGjMW1kKj1VqBdKpNxKBJQqGWJKvZqxKGCPxrVyGyB2",
  "lastValidBlockHeight": 245678910
}

Get user loans

Retrieve all active loans for a wallet address.

Function signature

GetUserLoans(params: {
  address: string;
}): Promise<{ loans: UserLoans[] }>

Parameters

address

string

required

Wallet public key to query loans for

Response

loans

UserLoans[]

Array of active loans

Show UserLoans properties

borrower

string

Borrower’s wallet address

pubkey

string

Loan account public key

borrowedAmount

string

Total borrowed amount in smallest units

expiredAt

string

Loan expiration timestamp (ISO 8601)

duration

number

Loan duration in seconds

liquidation

number

Liquidation threshold ratio

interest

string

Total interest amount. Note: 10 = 0.1%

principal

string

Principal token mint address

collateral

string

Collateral token mint address

collateralAmount

string

Collateral amount in smallest units

Example usage

import { GetUserLoans } from '@/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools';

const { loans } = await GetUserLoans({
  address: "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs",
});

console.log(`Found ${loans.length} active loans`);

loans.forEach(loan => {
  console.log(`Loan: ${loan.pubkey}`);
  console.log(`Amount: ${loan.borrowedAmount}`);
  console.log(`Expires: ${loan.expiredAt}`);
});

API endpoint

GET https://api-v3.rain.fi/api/loan/user?pubkey={address}&status=Ongoing&offset=0&limit=20

Response

{
  "user": "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs",
  "status": "Ongoing",
  "limit": 20,
  "offset": 0,
  "isAdmin": 0,
  "totalCount": 2,
  "ongoingCount": 2,
  "loans": [
    {
      "__t": "defi-loan",
      "pubkey": "8xKjzqKGqz8SjhXVy5tJGBR5Q2vC9YmKbW3pZrNfDxYz",
      "borrower": "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs",
      "borrowedAmount": "109821097",
      "expiredAt": "2026-03-11T12:00:00.000Z",
      "duration": 691200,
      "liquidation": 75,
      "interest": "0",
      "principal": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
      "collateral": "So11111111111111111111111111111111111111112",
      "collateralAmount": "1000000000"
    }
  ]
}

Interest values are stored as basis points. To convert to percentage, divide by 100. For example, "10" = 0.1%.

Repay loan

Repay an outstanding loan and reclaim collateral.

Function signature

RepayLoan(
  agent: SolanaAgentKit,
  params: RepayLoanRequest
): Promise<string>

Parameters

agent

SolanaAgentKit

required

Initialized Solana agent instance with wallet and connection

params

RepayLoanRequest

required

Loan repayment parameters

Show RepayLoanRequest properties

borrower

string

required

Borrower’s wallet address

amountIn

number

required

Amount to repay in smallest units (must cover principal + interest)

loan

string

required

Loan account public key from GetUserLoans

options

TransactionOptions

required

Transaction fee configuration

Show options properties

prioritizationFeeLamports

string

required

Priority fee level: "fast", "medium", or "slow"

maxFeeCapLamports

number

Maximum fee cap in lamports (optional)

jitoTipLamports

number

Jito MEV tip amount in lamports (optional)

Response

signature

string

Transaction signature after successful repayment

Example usage

import { GetUserLoans, RepayLoan } from '@/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools';

// Get active loans
const { loans } = await GetUserLoans({
  address: agent.wallet.publicKey.toString(),
});

if (loans.length > 0) {
  const loan = loans[0];
  
  // Calculate total repayment (principal + interest)
  const totalRepayment = parseFloat(loan.borrowedAmount) + parseFloat(loan.interest);
  
  // Repay the loan
  const signature = await RepayLoan(agent, {
    borrower: agent.wallet.publicKey.toString(),
    amountIn: totalRepayment,
    loan: loan.pubkey,
    options: {
      prioritizationFeeLamports: "fast",
      maxFeeCapLamports: 0,
      jitoTipLamports: 688925,
    },
  });
  
  console.log(`Loan repaid: ${signature}`);
}

API endpoint

POST https://api-v3.rain.fi/transaction-builder/defi/repay-loan

Request body
Response

{
  "borrower": "2gLAprD3LUJrSGdcXv88Nvi1ZfHRqpaL7c84SV7M4XWs",
  "amountIn": 109821097,
  "loan": "8xKjzqKGqz8SjhXVy5tJGBR5Q2vC9YmKbW3pZrNfDxYz",
  "isDefi": true,
  "options": {
    "prioritizationFeeLamports": "fast",
    "maxFeeCapLamports": 0,
    "jitoTipLamports": 688925
  }
}

{
  "transactions": ["AQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACAAQAHEb...base64..."],
  "version": 0,
  "kind": "defi-repay-loan",
  "blockhash": "9fGjKL2pNm34Qab7xVqRsEPYTnYXMKtn8mzR9yzgR4C3",
  "lastValidBlockHeight": 245679123
}

Ensure you have sufficient balance of the loan currency to cover the full repayment amount (principal + interest).

AI agent actions

All RainFi operations are also available as AI agent actions for natural language interaction.

RAINFI_QUOTE_LOAN_CALCULATOR

name

string

RAINFI_QUOTE_LOAN_CALCULATOR

similes

string[]

["quote loan calculator", "calculate loan", "get loan quote", "loan quote calculator"]

description

string

Calculate the loan quote for a given amount and currency. Currencies must be addresses, not symbols. Once you have the quote, display it to the user in a readable format before calling another tool.

RAINFI_TRANSACTION_BUILDER

name

string

RAINFI_TRANSACTION_BUILDER

similes

string[]

["build rainfi transaction", "execute loan transaction", "build loan transaction", "create rainfi transaction", "execute rainfi loan"]

description

string

Build and execute a loan transaction on RainFi using the loan quote parameters. The borrower is automatically set to the wallet public key.

RAINFI_GET_USER_LOANS

name

string

RAINFI_GET_USER_LOANS

similes

string[]

["get user loans", "get user loan"]

description

string

Get user loans from RainFi. Displays loans in a readable format, converts interest to percentage (10 = 0.1%), and converts amounts from smallest units to correct decimals.

RAINFI_REPAY_LOAN

name

string

RAINFI_REPAY_LOAN

similes

string[]

["repay loan", "repay loans"]

description

string

Repay a loan from RainFi using the provided loan account address.

Source code reference

Plugin index

~/workspace/source/utils/syntoUtils/agent/plugins/plugin-defi/index.ts:1

Quote calculator

~/workspace/source/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools/quoteLoanCalculator.ts:10

Transaction builder

~/workspace/source/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools/RainfiTransactionBuilder.ts:15

Get user loans

~/workspace/source/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools/GetUserLoans.ts:10

Repay loan

~/workspace/source/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/tools/RepayLoans.ts:15

Type definitions

~/workspace/source/utils/syntoUtils/agent/plugins/plugin-defi/rainfi/types/index.ts:1

Agent Core

Token Plugin

DeFi Plugin

Components

​Quote loan calculator

​Function signature

​Parameters

​Response

​Example usage

​API endpoint

​Build loan transaction

​Function signature

​Parameters

​Response

​Example usage

​API endpoint

​Get user loans

​Function signature

​Parameters

​Response

​Example usage

​API endpoint

​Repay loan

​Function signature

​Parameters

​Response

​Example usage

​API endpoint

​AI agent actions

​RAINFI_QUOTE_LOAN_CALCULATOR

​RAINFI_TRANSACTION_BUILDER

​RAINFI_GET_USER_LOANS

​RAINFI_REPAY_LOAN

​Source code reference

Plugin index

Quote calculator

Transaction builder

Get user loans

Repay loan

Type definitions

Build docs developers (and LLMs) love

Quote loan calculator

Function signature

Parameters

Response

Example usage

API endpoint

Build loan transaction

Function signature

Parameters

Response

Example usage

API endpoint

Get user loans

Function signature

Parameters

Response

Example usage

API endpoint

Repay loan

Function signature

Parameters

Response

Example usage

API endpoint

AI agent actions

RAINFI_QUOTE_LOAN_CALCULATOR

RAINFI_TRANSACTION_BUILDER

RAINFI_GET_USER_LOANS

RAINFI_REPAY_LOAN

Source code reference