other

Barista FIRE calculator. Simulates net worth growth through a full-time-saving phase and then a reduced-target phase funded partly by part-time/side income after quitting full-time work, until full financial independence is reached. Returns 400 for invalid or out-of-range inputs.

Gas mileage savings calculator. Compares annual fuel cost between two gas-powered vehicles based on miles driven, gas price, and each vehicle's MPG, and computes the break-even point for any price premium of the more efficient vehicle. Returns 400 for invalid or out-of-range inputs.

Alcohol spending and opportunity-cost calculator. Sums home and going-out drinking costs plus associated rideshare costs into monthly and yearly totals, then projects what that redirected spending could grow into if invested instead, using the future-value-of-an-annuity formula. Returns 400 for invalid or out-of-range inputs.

Unit conversion for length, mass, volume, and temperature using exact conversion factors (temperature uses the correct affine formulas, not simple multiplication). Returns 400 for unsupported units or categories.

Line-based diff between two strings using the Myers diff algorithm (via the diff/jsdiff library), returning a list of equal/add/remove operations. Returns 400 for input over the 50,000-character length cap or 2,000-line cap.

Compound interest calculator. Projects the ending value of an investment given a starting principal, monthly contributions, and an annual interest rate, compounded monthly over a chosen number of years. Returns 400 for invalid or out-of-range inputs.

Base64 decoder API. Decodes a base64 string back to UTF-8 text instantly and correctly, avoiding the padding and charset errors LLMs make when decoding base64 by hand. Returns 400 if text is missing, not a string, or not valid base64.

Coast FIRE calculator. Computes the lump sum needed today, invested with zero further contributions, to grow into your full retirement number by your target retirement age, plus (given an ongoing monthly contribution) a year-by-year projection of when your actual trajectory crosses that lump sum. Returns 400 for invalid or out-of-range inputs.

Purchase impact on FIRE timeline calculator. Runs the FIRE net-worth simulation twice — with and without a one-time purchase amount deducted at a given year — and reports how many years that purchase delays financial independence, quantifying its true opportunity cost. Returns 400 for invalid or out-of-range inputs.

Periodic table element lookup by symbol or atomic number, returning name, atomic mass, and category. Covers the most commonly referenced elements. Returns 400 if neither symbol nor atomicNumber is provided, or the element is not found.

Lookup of standard physical constants (speed of light, gravitational constant, Planck constant, elementary charge, Avogadro number, Boltzmann constant, gas constant, electron mass) with exact published CODATA values. Returns 400 for an unrecognized constant name.

Sunrise, sunset, solar noon, day length, and moon phase for a given latitude/longitude/date, computed via the suncalc library (standard solar/lunar position algorithms) — precise astronomical math an LLM cannot reliably compute mentally. Returns 400 for out-of-range coordinates or an invalid date.

HSA (Health Savings Account) growth calculator. Projects year-by-year account balance from a starting value, annual contributions, annual expense withdrawals, and an annual return rate. Returns 400 for invalid or out-of-range inputs.

15-year vs 30-year mortgage comparison calculator. Computes monthly payment and total interest for both loan terms on the same purchase price and down payment, and reports the payment and lifetime-interest tradeoff between them. Returns 400 for invalid or out-of-range inputs.

Portfolio rebalancing calculator. Given current holdings and target allocation percentages, computes the dollar gap per asset and the monthly buy/sell inflow needed to reach the target allocation over a chosen rebalancing period. Returns 400 for invalid or out-of-range inputs.

Converts a color between hex, rgb, and hsl representations using exact arithmetic. Returns 400 for a malformed or out-of-range color value.

Scientific unit conversion for pressure, energy, and molarity using exact conversion factors. Returns 400 for unsupported units or categories.

Solves a system of linear equations (Ax = b) using the ml-matrix library's LU decomposition (LuDecomposition), with a near-singularity guard beyond the library's exact-singular check, for systems up to 20x20. Returns 400 for malformed, mismatched-size, non-finite, oversized, or non-unique/near-singular-solution systems.

Safe arithmetic expression evaluator. Parses and evaluates expressions with +, -, *, /, ^, and parentheses using a bounded-recursion parser (no eval/Function), avoiding the arithmetic slips an LLM makes on long expressions. Returns 400 for invalid, oversized, or division-by-zero expressions.

Computes the next N run times for a standard 5-field cron expression, avoiding the mental cron-schedule simulation an LLM often gets subtly wrong. Returns 400 for an invalid expression or an out-of-range count.

Validates a JSON document against a JSON Schema using the industry-standard ajv validator, returning whether it is valid and a list of human-readable error messages if not. Returns 400 for a malformed schema or oversized input.

Normalize a receipt, invoice, or order confirmation into a canonical structured purchase record.

Observe a structured workflow event and return an advisory Decision (nominal|watch|throttle|pause|human_review). Actuation is OFF; authority is none. No outbound calls. Optional tenant_id selects the in-memory tenant Map (Durable Object later).

Attested resolution: is at least one NOAA/NWS alert at or above a requested severity active for a covered station's point right now? Evidence bundle with the hash-attested alerts payload and alert count, capped by an aye/nay receipt — never a bare boolean. Refusals are free.