What filing statuses are supported?
single, married_joint, and head_of_household. Each has its own standard deduction and bracket thresholds for the selected tax year.
Income Tax API
Bracket-by-Bracket
2024 Tax Year
Keyless Dataset
Tax estimates. Down to the bracket.
Send gross income and filing status, get back a full federal tax breakdown — effective rate, marginal rate, bracket-by-bracket detail, and optional state and credit blending.
3 · filing statusesBracket · breakdownState · rate blendingTax · credits supported
Estimate federal tax, instantly.
This calls the live Income Tax API. Enter gross income, pick a filing status, and see the full breakdown.
Request builder
Income and filing status in, full breakdown out.
GET /income-tax
Tax year 2024
Brackets and the standard deduction are pinned to the 2024 snapshot. Add stateRate or taxCredits query parameters for a blended, credit-adjusted total.
Output preview
Live response from the API, plus the exact request to reproduce it.
Calculating estimate...
Why Income Tax API
Tax math, done server-side.
Full federal estimate
One call returns taxable income, total tax, effective rate, marginal rate, and a monthly equivalent.
Bracket-by-bracket breakdown
The breakdown array shows the amount taxed and tax owed at each bracket rate, useful for tax-planning UIs.
Three filing statuses
single, married_joint, and head_of_household, each with its own standard deduction and bracket thresholds.
State-rate blending
Pass stateRate (0-20%) for a combined federal + state estimate without a second API call.
Tax-credit support
Apply taxCredits after the bracket calculation for a floored, credit-adjusted total federal tax figure.
Deterministic, keyless dataset
No upstream provider or key required — GET /brackets and /catalog expose the exact rules behind every estimate.
/api/v1/income-tax
Endpoints, at a glance.
One estimate endpoint plus bracket and catalog discovery — all GET, all deterministic against the 2024 snapshot.
GET/api/v1/income-tax
Tax estimate
Estimates federal income tax and optional state-adjusted totals, with optional post-calculation tax credits. Requires income.
GET/api/v1/income-tax/brackets
Bracket schedule
Filing-status bracket thresholds and standard deduction for a supported tax year.
GET/api/v1/income-tax/catalog
Catalog
Supported filing statuses and tax years.
GET/health
Service health
Service health status.
| Parameter | Type | Required | Description |
|---|---|---|---|
| income | number | yes* | Gross annual income. Required for the estimate endpoint. |
| filingStatus | string | no | single, married_joint, or head_of_household. Defaults to single. |
| taxYear | integer | no | Tax year selector. Currently supports 2024. |
| deductions | number | no | Additional deductions beyond the standard deduction. |
| taxCredits | number | no | Non-negative federal tax credits applied after bracket calculation. |
| stateRate | number | no | Optional state income-tax rate (0-20%) for a blended estimate. |
Error reference
Failures you can plan for.
Every response includes a success flag and a correlationId for tracing.
400Validation Error
Invalid query parameters or an unsupported filing status.
401Authentication Error
Missing or invalid gateway API key. Send x-api-key or api_key with every request.
404Not Found
Unknown route under /api/v1/income-tax.
429Rate Limit Error
More than 200 requests in a 15-minute window per IP.
502Processing Error
Unexpected internal failure while computing the estimate.
Example error response
{
"success": false,
"error": "income must be a non-negative number",
"correlationId": "1784853204062-fs8j2p9z1"
}FAQ
API questions developers ask first.
How is the tax estimate calculated?
Gross income minus the standard deduction and any additional deductions gives taxable income, which is run through the bracket schedule. The breakdown array shows the amount and tax owed for each bracket.
Can I include state tax and credits?
Yes. Pass stateRate (0-20%) for a blended federal + state estimate, and taxCredits to apply non-refundable credits after the bracket calculation, floored at zero.
Which tax years are supported?
The bundled bracket snapshot is tax year 2024. GET /brackets and /catalog expose the filing statuses and years with data so integrations can validate input before calling the estimate endpoint.
Do I need an API key just to see the tax brackets?
The tax data itself is keyless and deterministic, but requests still route through the Datpaq gateway, so send your Datpaq API key as an x-api-key header or api_key query parameter.
Add tax estimates in one request.
Gross income and filing status in, a full federal tax breakdown out — brackets, rates, and optional state and credit blending included.