# Tollbooth (x402toll.com)

> 59 verified, pay-per-call financial, tax, and legal calculators for AI agents. Every call returns the answer, the exact 2026 source it came from, a formula trace, and a reproducible SHA-256 hash you can re-verify for free. Paid over x402 (USDC on Base); prices from $0.02.

Free (no payment): GET /v1/catalog · GET /v1/openapi.json · POST /v1/preview/:id · POST /v1/verify-hash · GET /v1/golden/:id · POST /v1/verify · POST /v1/gvp/check · GET /v1/spec · POST /v1/recommend · GET /v1/stats
Neutral verifier: POST /v1/verify (free — confirm/deny any claim, leak-safe) · POST /v1/gvp/check (free — GVP-conformance check + verified-answer badge for ANY service) · POST /v1/verify/batch ($5 — signed, filable compliance report) · POST /v1/receipt/:id ($1/$5 — audit-grade signed receipt).

## Payroll & tax
- [paycheck](https://x402toll.com/v1/paycheck) ($0.05): US net-paycheck breakdown for any of 51 jurisdictions: 2026 federal brackets, FICA (SS wage base $184,500, additional Medicare), and state income tax. Golden-vector verified.
- [relocation-paycheck](https://x402toll.com/v1/reports/relocation-paycheck) ($1.00): The same salary across all 51 US jurisdictions, ranked by net take-home — the relocation what-if in one call, with per-state tax detail and the best-to-worst annual spread.
- [self-employment-tax](https://x402toll.com/v1/tax/self-employment) ($0.05): Self-employment (SE) tax on Schedule C net profit — Social Security to the 2026 $184,500 wage base, Medicare, Additional Medicare, and the deductible half.
- [estimated-tax](https://x402toll.com/v1/tax/estimated) ($0.10): Quarterly estimated-tax safe harbor (Form 1040-ES): the required annual payment and per-quarter amount to avoid an underpayment penalty.
- [capital-gains-tax](https://x402toll.com/v1/tax/capital-gains) ($0.10): Federal capital-gains tax: long-term stacked across the 2026 0%/15%/20% breakpoints, short-term at ordinary marginal rates, plus the 3.8% Net Investment Income Tax.
- [federal-income-tax](https://x402toll.com/v1/tax/federal-income) ($0.05): Federal income tax on ordinary income for 2026: AGI from gross minus above-the-line adjustments, standard or itemized deduction, the 2026 brackets, and a flat nonrefundable credit amount. Distinct from /v1/paycheck (which nets FICA + state per pay period).
- [state-income-tax](https://x402toll.com/v1/tax/state-income) ($0.05): Standalone 2026 state income tax for any of 51 US jurisdictions — progressive/flat/no-tax schedules, MFJ doubling — applied to the income you provide.
- [bonus-tax](https://x402toll.com/v1/tax/bonus) ($0.05): Withholding and net take-home on a bonus/commission using the 2026 federal supplemental-wage rate (22% flat; 37% on cumulative supplemental wages over $1M), plus FICA and an optional state supplemental rate.
- [overtime-pay](https://x402toll.com/v1/tax/overtime) ($0.02): FLSA overtime pay: regular and overtime hours, the overtime rate, and gross pay for a week — federal 1.5× over 40 hours by default, any threshold/multiplier configurable.
- [1099-vs-w2](https://x402toll.com/v1/tax/1099-vs-w2) ($0.10): Take-home comparison of the same pay as a W-2 employee vs a 1099 contractor — employee FICA vs self-employment tax (with the half-SE deduction) — and the higher contractor rate needed to match.
- [tax-estimate-report](https://x402toll.com/v1/reports/tax-estimate) ($1.00): Full 2026 tax estimate in one call: federal income tax + self-employment tax + employee FICA + state income tax, from wages, self-employment income, and other income — with the component breakdown, effective and marginal rates, and after-tax income.
- [quarterly-estimate-package](https://x402toll.com/v1/reports/quarterly-package) ($1.00): Quarterly estimated-tax package (Form 1040-ES): derives your current-year total tax (federal income + self-employment + FICA + state) from income, applies the safe harbor (lesser of 90% current or 100%/110% prior-year tax), and returns the four equal 2026 installments net of withholding with their due dates.

## Real estate
- [mortgage-affordability](https://x402toll.com/v1/mortgage-affordability) ($0.05): Self-employed mortgage affordability: 2-year income averaging with add-backs, the declining-income rule, front/back DTI limits, PMI-aware max-price solve.
- [cap-rate](https://x402toll.com/v1/realestate/cap-rate) ($0.05): Rental property returns: cap rate (unleveraged), cash-on-cash (leveraged), gross rent multiplier, and the 1% rule.
- [pmi](https://x402toll.com/v1/realestate/pmi) ($0.05): Monthly PMI cost and the month it auto-cancels (at 78% of original value, per the Homeowners Protection Act).
- [arm](https://x402toll.com/v1/realestate/arm) ($0.05): Adjustable-rate mortgage payment shock: the payment before and after the first reset, and the increase.
- [home-affordability](https://x402toll.com/v1/realestate/affordability) ($0.05): Max home price a W-2 buyer can afford from income and debts, using front/back DTI limits and a PMI-aware price solve.
- [rent-vs-buy](https://x402toll.com/v1/realestate/rent-vs-buy) ($0.25): Rent vs buy over a horizon: year-by-year renting cost vs net cost of owning (crediting equity + appreciation, net of selling costs), with the break-even year.

## Business
- [llc-cost](https://x402toll.com/v1/llc-cost) ($0.05): LLC formation cost for any US state + DC: filing fee, annual/biennial report, franchise tax, publication requirements — Year-1 and 5-year totals from each state's own 2026 fee schedule.
- [llc-50-state](https://x402toll.com/v1/reports/llc-50-state) ($0.50): All 51 US jurisdictions ranked by true 5-year LLC cost — filing, reports, franchise taxes, publication requirements — with per-state notes.
- [s-corp-salary](https://x402toll.com/v1/business/s-corp-salary) ($0.10): S-corp reasonable-salary employment-tax saving: SE tax a sole proprietor pays on all profit vs FICA an S-corp pays on just the salary, with the distribution that escapes self-employment tax.
- [entity-tax-compare](https://x402toll.com/v1/business/entity-compare) ($0.10): Total 2026 federal tax as a sole proprietor / LLC vs S-corp vs C-corp for the same profit — SE tax vs FICA vs 21% corporate tax with qualified-dividend double taxation — ranked to the lowest.

## Lending
- [debt-plan](https://x402toll.com/v1/reports/debt-plan) ($0.25): Full debt-payoff report: avalanche vs snowball simulated month-by-month with debt rollover — payoff order, debt-free month, total interest, and the exact gap between strategies.
- [loan-amortization](https://x402toll.com/v1/lending/amortization) ($0.05): Amortized monthly payment, total interest, and a year-by-year balance schedule for any loan.
- [mortgage-payment](https://x402toll.com/v1/lending/mortgage-payment) ($0.05): Full monthly mortgage payment (PITI): principal & interest, property tax, insurance, PMI (auto when LTV > 80%), and HOA.
- [auto-loan](https://x402toll.com/v1/lending/auto-loan) ($0.05): Auto-loan payment including state sales tax (verified 2026 rates), trade-in credit, down payment, and fees.
- [refinance-breakeven](https://x402toll.com/v1/lending/refinance) ($0.05): Refinance analysis: new payment, monthly savings, months to break even on closing costs, and lifetime interest saved.
- [dti](https://x402toll.com/v1/lending/dti) ($0.02): Debt-to-income ratio — front-end and back-end — with pass/fail against your (or the conventional 28/36) limits.
- [extra-payment](https://x402toll.com/v1/lending/extra-payment) ($0.05): How much time and interest an extra monthly payment saves on a loan.
- [mortgage-points](https://x402toll.com/v1/lending/mortgage-points) ($0.05): Whether buying discount points pays off: monthly savings from the rate buydown and the break-even month.
- [apr](https://x402toll.com/v1/lending/apr) ($0.05): True APR (Reg Z / TILA) from the note rate plus financed fees — the real cost of borrowing.
- [heloc-payment](https://x402toll.com/v1/lending/heloc) ($0.05): HELOC payments: interest-only during the draw period and the amortizing payment when repayment begins (the payment jump).
- [loan-comparison](https://x402toll.com/v1/lending/compare) ($0.05): Compare 2–6 loan offers by true total cost (payments + fees) and rank them.
- [mortgage-qualification](https://x402toll.com/v1/reports/mortgage-qualification) ($1.00): Self-employed mortgage qualification worksheet: 2-year-average (or declining-income) qualifying income with add-backs, front/back DTI limits, the max home price you qualify for, and the full monthly PITI (principal, interest, tax, insurance, PMI, HOA) at that price. The flagship engine, as an agent-callable signed report.

## Crypto & DeFi
- [crypto-tax-lot](https://x402toll.com/v1/crypto/tax-lots) ($0.25): Match a crypto sale against buy lots (FIFO / LIFO / HIFO), returning realized gain/loss split short- vs long-term (IRS >365-day rule) plus the remaining lots.
- [impermanent-loss](https://x402toll.com/v1/crypto/impermanent-loss) ($0.05): Impermanent loss for a 50/50 constant-product LP position vs simply holding, given the price change of the volatile asset.
- [apr-apy](https://x402toll.com/v1/crypto/apr-apy) ($0.02): Convert between APR and APY at any compounding frequency (or continuous).
- [liquidation-price](https://x402toll.com/v1/crypto/liquidation-price) ($0.05): Liquidation price for a leveraged long or short (isolated margin), plus the % move to liquidation.
- [yield-compare](https://x402toll.com/v1/crypto/yield-compare) ($0.05): Rank up to 10 stablecoin/yield options by projected return over a horizon at each stated APY.

## Retirement
- [401k-match](https://x402toll.com/v1/retirement/401k) ($0.05): 401(k) contribution vs the 2026 limits (incl. age 50+ and 60–63 catch-ups) plus the employer match, capped at the §415(c) total.
- [ira-limits](https://x402toll.com/v1/retirement/ira-limits) ($0.05): 2026 IRA / Roth contribution limit for your situation — including the Roth MAGI phase-out and traditional-deduction phase-out (if covered by a workplace plan).
- [rmd](https://x402toll.com/v1/retirement/rmd) ($0.10): Required Minimum Distribution from a traditional IRA/401(k) using the IRS Uniform Lifetime Table — the amount you must withdraw at your age, given the prior year-end balance. RMDs begin at 73 (SECURE 2.0).
- [roth-conversion](https://x402toll.com/v1/retirement/roth-conversion) ($0.10): Federal tax cost of a Roth conversion in one year: the extra income tax from stacking the converted amount on top of your other taxable income, with the marginal rate before and after.
- [social-security](https://x402toll.com/v1/retirement/social-security) ($0.25): Social Security monthly benefit estimate from your AIME: the 2026 PIA bend-point formula plus the claim-age adjustment (62 pays 70%, FRA 67 pays 100%, 70 pays 124%).
- [hsa-fsa](https://x402toll.com/v1/retirement/hsa-fsa) ($0.05): 2026 HSA or health-FSA contribution limit and income-tax savings — HSA self/family limits + age-55 catch-up + HDHP deductible/OOP bounds, or the FSA salary-reduction limit + carryover.
- [retirement-readiness](https://x402toll.com/v1/reports/retirement-readiness) ($1.00): Retirement-readiness projection: your savings grown to retirement age, the nest egg the 4%-rule requires for your target income, the surplus or gap, and the extra monthly contribution to close it.

## Commerce
- [margin-markup](https://x402toll.com/v1/commerce/margin) ($0.02): Margin, markup, and profit from cost — give cost plus any one of price, target margin %, or markup %, and it solves the rest.
- [discount](https://x402toll.com/v1/commerce/discount) ($0.02): Sale price after one or more stacked percentage discounts (applied sequentially, not summed) plus an optional flat amount off.
- [tip-split](https://x402toll.com/v1/commerce/tip-split) ($0.01): Tip amount, total, and per-person split for a restaurant bill.
- [break-even](https://x402toll.com/v1/commerce/break-even) ($0.05): Break-even units and revenue (CVP): where contribution margin covers fixed costs.
- [order-total](https://x402toll.com/v1/commerce/order-total) ($0.02): Order total from subtotal, discount, tax rate, and shipping — tax excludes shipping by default (toggle with taxShipping).
- [roi-roas](https://x402toll.com/v1/commerce/roi) ($0.02): ROI %, ROAS, profit, and profit margin from revenue and cost (e.g. ad spend).
- [sales-tax](https://x402toll.com/v1/commerce/sales-tax) ($0.05): US sales tax — add or remove tax using the verified 2026 STATE base rate for any state + DC, plus an optional local rate. Flags gross-receipts states (HI/NM) and local-only states (AK).
- [vat-gst](https://x402toll.com/v1/commerce/vat-gst) ($0.05): VAT / GST for 16 major economies (UK, EU, Australia, Canada, Japan, Singapore, UAE, India, and more) at the verified 2026 standard rate — add or remove.
- [processor-fee](https://x402toll.com/v1/commerce/processor-fee) ($0.02): Payment-processor fee and net received for Stripe, PayPal, and Square at their verified 2026 standard US rates — or reverse gross-up (what to charge to net a target).
- [marketplace-fee](https://x402toll.com/v1/commerce/marketplace-fee) ($0.05): Seller fees and net payout for Amazon, eBay, and Etsy at their verified 2026 standard fee schedules (Amazon referral %, eBay final value fee, Etsy listing + transaction + processing).

## Investing
- [npv-irr](https://x402toll.com/v1/investing/npv-irr) ($0.05): Net present value and internal rate of return for a cash-flow series (index 0 = today, usually a negative outlay), plus the profitability index and an accept/reject call.
- [bond-yield](https://x402toll.com/v1/investing/bond-yield) ($0.05): Bond current yield and yield-to-maturity from face value, coupon, market price, and maturity — with the premium/discount/par classification.
- [capital-gains-scenario](https://x402toll.com/v1/reports/capital-gains-scenario) ($1.00): Multi-year capital-gains plan: realize a long-term gain all at once vs spread it evenly across N years, with the federal tax for each path (2026 0/15/20% long-term bands + the 3.8% NIIT) and the tax saved by spreading — the signed record an investor or agent uses to pick when to realize gains.