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Finance API

22 endpoints for finance workflows. Every call requires bearer authentication and uses the standard ToolsOnDuty response envelope.

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EndpointAPI key

principal *annualRatePercent *term *termUnit

POST/v1/finance/loan1 credit / call

Loan payment calculator

Amortizing loan payment, total payment and total interest.

Parameter	Type	Required	Description
principal	number	Yes	Loan amount.
annualRatePercent	number	Yes	Annual interest rate (%).
term	number	Yes	Loan term.
termUnit	string	No	years \| months. Default: years.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/loan \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"principal":200000,"annualRatePercent":6,"term":30,"termUnit":"years"}'

Response

{
  "ok": true,
  "data": {
    "monthlyPayment": 1199.1
  }
}

POST/v1/finance/emi1 credit / call

EMI calculator

Equated monthly installment, total interest and total amount payable (same amortizing formula as finance/loan).

Parameter	Type	Required	Description
principal	number	Yes	Loan amount.
annualRatePercent	number	Yes	Annual interest rate (%).
term	number	Yes	Loan term.
termUnit	string	No	years \| months. Default: years.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/emi \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"principal":500000,"annualRatePercent":9,"term":60,"termUnit":"months"}'

Response

{
  "ok": true,
  "data": {
    "emi": 10379.09
  }
}

POST/v1/finance/simple-interest1 credit / call

Simple interest

Simple interest and total amount: SI = P x R x T / 100.

Parameter	Type	Required	Description
principal	number	Yes	Principal amount.
annualRatePercent	number	Yes	Annual interest rate (%).
time	number	Yes	Time period.
timeUnit	string	No	years \| months. Default: years.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/simple-interest \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"principal":1000,"annualRatePercent":5,"time":2}'

Response

{
  "ok": true,
  "data": {
    "interest": 100,
    "total": 1100
  }
}

POST/v1/finance/compound-interest1 credit / call

Compound interest

Compound interest future value and total interest: A = P(1 + r/n)^(nt).

Parameter	Type	Required	Description
principal	number	Yes	Principal amount.
annualRatePercent	number	Yes	Annual interest rate (%).
time	number	Yes	Time period.
timeUnit	string	No	years \| months. Default: years.
frequency	string	No	annually \| semiannually \| quarterly \| monthly \| daily. Default: annually.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/compound-interest \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"principal":1000,"annualRatePercent":5,"time":10,"frequency":"monthly"}'

Response

{
  "ok": true,
  "data": {
    "futureValue": 1647.01,
    "interest": 647.01
  }
}

POST/v1/finance/investment1 credit / call

Investment growth

Future value of an initial investment plus regular contributions, with total contributions and growth.

Parameter	Type	Required	Description
initial	number	Yes	Initial investment amount.
contribution	number	Yes	Regular contribution amount.
contributionFrequency	string	No	monthly \| quarterly \| annually. Default: monthly.
annualReturnPercent	number	Yes	Expected annual return (%).
years	number	Yes	Investment period in years.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/investment \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"initial":1000,"contribution":100,"annualReturnPercent":7,"years":10}'

Response

{
  "ok": true,
  "data": {
    "futureValue": 18415
  }
}

POST/v1/finance/roi1 credit / call

Return on investment

ROI percentage and profit or loss from an initial investment and final value.

Parameter	Type	Required	Description
initialInvestment	number	Yes	Initial investment amount.
finalValue	number	Yes	Final value.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/roi \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"initialInvestment":1000,"finalValue":1250}'

Response

{
  "ok": true,
  "data": {
    "roiPercent": 25,
    "profit": 250
  }
}

POST/v1/finance/savings1 credit / call

Savings growth

Future value of a savings balance with regular contributions.

Parameter	Type	Required	Description
startingBalance	number	Yes	Starting balance.
contribution	number	Yes	Regular contribution amount.
contributionFrequency	string	No	monthly \| quarterly \| annually. Default: monthly.
annualRatePercent	number	Yes	Annual interest rate (%).
years	number	Yes	Savings period in years.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/savings \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"startingBalance":5000,"contribution":200,"annualRatePercent":4,"years":5}'

Response

{
  "ok": true,
  "data": {
    "futureValue": 18424
  }
}

POST/v1/finance/mortgage1 credit / call

Mortgage calculator

Mortgage loan amount, monthly payment and totals, with optional property tax and insurance.

Parameter	Type	Required	Description
homePrice	number	Yes	Home price.
downPayment	number	Yes	Down payment.
annualRatePercent	number	Yes	Annual interest rate (%).
termYears	number	Yes	Loan term in years.
annualPropertyTax	number	No	Annual property tax. Default: 0.
annualHomeInsurance	number	No	Annual home insurance. Default: 0.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/mortgage \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"homePrice":400000,"downPayment":80000,"annualRatePercent":6,"termYears":30}'

Response

{
  "ok": true,
  "data": {
    "monthlyTotal": 1918.6
  }
}

POST/v1/finance/amortization1 credit / call

Amortization schedule

Payment, totals and a principal/interest schedule (capped to 60 rows) for a loan.

Parameter	Type	Required	Description
loanAmount	number	Yes	Loan amount.
annualRatePercent	number	Yes	Annual interest rate (%).
termYears	number	Yes	Loan term in years.
frequency	string	No	monthly \| quarterly \| annually. Default: monthly.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/amortization \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"loanAmount":100000,"annualRatePercent":5,"termYears":15}'

Response

{
  "ok": true,
  "data": {
    "payment": 790.79,
    "totalInterest": 42342
  }
}

POST/v1/finance/interest-rate1 credit / call

Interest rate solver

Derive the nominal and effective annual interest rate from a principal, final amount, time and compounding frequency.

Parameter	Type	Required	Description
principal	number	Yes	Starting principal.
finalAmount	number	Yes	Final amount.
time	number	Yes	Time period.
timeUnit	string	No	years \| months. Default: years.
frequency	string	No	annually \| semiannually \| quarterly \| monthly \| daily. Default: annually.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/interest-rate \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"principal":1000,"finalAmount":1500,"time":5}'

Response

{
  "ok": true,
  "data": {
    "nominalRatePercent": 8.45,
    "effectiveRatePercent": 8.45
  }
}

POST/v1/finance/discount1 credit / call

Discount calculator

Discount amount, final price and savings from an original price and discount percent.

Parameter	Type	Required	Description
originalPrice	number	Yes	Original price.
discountPercent	number	Yes	Discount percentage (0-100).

Request

curl -X POST https://toolsonduty.com/api/v1/finance/discount \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"originalPrice":80,"discountPercent":25}'

Response

{
  "ok": true,
  "data": {
    "discountAmount": 20,
    "finalPrice": 60,
    "saved": 20
  }
}

POST/v1/finance/percentage-off1 credit / call

Percentage-off calculator

Amount off and final sale price for a price and percentage off (same math as finance/discount).

Parameter	Type	Required	Description
price	number	Yes	Original price.
percentOff	number	Yes	Percentage off (0-100).

Request

curl -X POST https://toolsonduty.com/api/v1/finance/percentage-off \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"price":80,"percentOff":25}'

Response

{
  "ok": true,
  "data": {
    "amountOff": 20,
    "finalPrice": 60
  }
}

POST/v1/finance/profit-margin1 credit / call

Profit margin calculator

Profit, profit margin percentage and markup percentage from revenue and cost.

Parameter	Type	Required	Description
revenue	number	Yes	Revenue.
cost	number	Yes	Cost.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/profit-margin \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"revenue":150,"cost":100}'

Response

{
  "ok": true,
  "data": {
    "profit": 50,
    "marginPercent": 33.33,
    "markupPercent": 50
  }
}

POST/v1/finance/vat1 credit / call

VAT calculator

Add or remove VAT (or any percentage tax) from an amount: net, tax and gross.

Parameter	Type	Required	Description
amount	number	Yes	Amount.
ratePercent	number	Yes	VAT rate (%).
mode	string	No	add \| remove. Default: add.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/vat \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"amount":100,"ratePercent":20,"mode":"add"}'

Response

{
  "ok": true,
  "data": {
    "netAmount": 100,
    "taxAmount": 20,
    "grossAmount": 120
  }
}

POST/v1/finance/sales-tax1 credit / call

Sales tax calculator

Sales tax amount and total price for a price and tax rate.

Parameter	Type	Required	Description
price	number	Yes	Price before tax.
ratePercent	number	Yes	Sales tax rate (%).

Request

curl -X POST https://toolsonduty.com/api/v1/finance/sales-tax \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"price":50,"ratePercent":8.5}'

Response

{
  "ok": true,
  "data": {
    "taxAmount": 4.25,
    "totalPrice": 54.25
  }
}

POST/v1/finance/tip1 credit / call

Tip calculator

Tip amount, total bill and per-person split.

Parameter	Type	Required	Description
billAmount	number	Yes	Bill amount.
tipPercent	number	Yes	Tip percentage.
people	number	No	Number of people splitting the bill. Default: 1.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/tip \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"billAmount":100,"tipPercent":18,"people":4}'

Response

{
  "ok": true,
  "data": {
    "tipAmount": 18,
    "totalBill": 118,
    "perPerson": 29.5
  }
}

POST/v1/finance/salary1 credit / call

Salary converter

Convert a salary across hourly, daily, weekly, monthly and annual pay periods.

Parameter	Type	Required	Description
amount	number	Yes	Salary amount.
frequency	string	Yes	hourly \| daily \| weekly \| monthly \| annual.
hoursPerDay	number	No	Work hours per day. Default: 8.
daysPerWeek	number	No	Work days per week. Default: 5.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/salary \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"amount":60000,"frequency":"annual"}'

Response

{
  "ok": true,
  "data": {
    "hourly": 28.85,
    "monthly": 5000
  }
}

POST/v1/finance/take-home1 credit / call

Take-home pay estimator

Estimate take-home pay from a gross salary, a deduction percentage and optional fixed deductions.

Parameter	Type	Required	Description
grossSalary	number	Yes	Gross salary.
deductionPercent	number	Yes	Deduction percentage (0-100).
otherDeductions	number	No	Additional fixed deductions. Default: 0.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/take-home \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"grossSalary":60000,"deductionPercent":20}'

Response

{
  "ok": true,
  "data": {
    "grossSalary": 60000,
    "deductionAmount": 12000,
    "takeHome": 48000
  }
}

POST/v1/finance/debt-to-income1 credit / call

Debt-to-income ratio

DTI percentage and an interpretation band (lower | moderate | higher) from monthly income and debt.

Parameter	Type	Required	Description
monthlyIncome	number	Yes	Gross monthly income.
monthlyDebt	number	Yes	Total monthly debt payments.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/debt-to-income \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"monthlyIncome":5000,"monthlyDebt":1500}'

Response

{
  "ok": true,
  "data": {
    "dtiPercent": 30,
    "category": "lower"
  }
}

POST/v1/finance/retirement1 credit / call

Retirement savings estimator

Estimated retirement savings, contributions and investment growth from current age, retirement age, savings and monthly contribution.

Parameter	Type	Required	Description
currentAge	number	Yes	Current age.
retirementAge	number	Yes	Target retirement age (must exceed current age).
currentSavings	number	Yes	Current retirement savings.
monthlyContribution	number	Yes	Monthly contribution.
annualReturnPercent	number	Yes	Expected annual return (%).

Request

curl -X POST https://toolsonduty.com/api/v1/finance/retirement \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"currentAge":30,"retirementAge":65,"currentSavings":20000,"monthlyContribution":500,"annualReturnPercent":7}'

Response

{
  "ok": true,
  "data": {
    "futureSavings": 963000
  }
}

POST/v1/finance/inflation1 credit / call

Inflation calculator

Future cost, purchasing power and total inflation from a current amount, inflation rate and number of years.

Parameter	Type	Required	Description
currentAmount	number	Yes	Current amount.
inflationRate	number	Yes	Annual inflation rate (%).
years	number	Yes	Number of years.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/inflation \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"currentAmount":1000,"inflationRate":3,"years":10}'

Response

{
  "ok": true,
  "data": {
    "futureCost": 1343.92
  }
}

POST/v1/finance/invoice1 credit / call

Invoice totals calculator

Validate line items and calculate subtotal, fixed discount, tax and total; this endpoint does not render a document.

Parameter	Type	Required	Description
items	string	Yes	JSON array of {description, quantity, unitPrice} objects.
taxRate	number	No	Tax percentage from 0 to 100. Default: 0.
discount	number	No	Fixed discount amount. Default: 0.

Request

curl -X POST https://toolsonduty.com/api/v1/finance/invoice \
  -H "Authorization: ******" \
  -H "Content-Type: application/json" \
  -d '{"items":"[{\"description\":\"Service\",\"quantity\":2,\"unitPrice\":50}]","taxRate":10}'

Response

{
  "ok": true,
  "data": {
    "subtotal": 100,
    "tax": 10,
    "total": 110
  }
}