#conversion

Water-hardness maths as an API, computed locally and deterministically. The convert endpoint converts a hardness value between all the common units — parts per million / milligrams per litre as calcium carbonate, grains per US gallon, German degrees (°dH), French degrees (°f), English or Clark degrees, and millimoles per litre — passing everything through ppm (1 gpg = 17.118 ppm, 1 °dH = 17.848, 1 °f = 10, 1 °Clark = 14.254), and classifies the result. The classify endpoint labels a value as soft, moderately hard, hard or very hard on the USGS/WHO scale. The softener endpoint sizes a water softener: from the hardness and the household water use it works out the grains of hardness removed per day and the grain capacity needed between regenerations. Everything is computed locally and deterministically, so it is instant and private. Ideal for water-treatment and plumbing tools, aquarium and pool apps, appliance and softener sizing, and home and lab software. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is water-hardness conversion; for general unit conversion use a unit-conversion API and for swimming-pool dosing use a pool API.

api.oanor.com/hardness-api

Render tabular data as an HTML table, and parse an HTML table back into data. The render endpoint turns a JSON array (of objects, or of arrays) or CSV into a clean, semantic <table> with <thead>/<tbody>, an optional caption and CSS class — every cell HTML-escaped so it is safe to embed. The parse endpoint does the reverse: give it any HTML containing a table and get back the headers, the rows and a ready-to-use JSON array of objects, with entities decoded and tags stripped from each cell. Perfect for emails and reports, dashboards and admin screens, and scraping or migrating tabular content. Pure local computation — no key, no third-party service, instant; up to 2 MB via POST. Live, nothing stored. 3 endpoints. Distinct from Markdown/ASCII table rendering and from generic HTML extraction.

api.oanor.com/htmltable-api

Recipe and kitchen conversions as an API. Convert between volume units (teaspoon, tablespoon, cup, fl-oz, ml, litre, pint, quart, gallon) and between mass units (gram, kilogram, ounce, pound) — and, crucially, between volume and mass for a specific ingredient using its density, so 1 cup of all-purpose flour ≈ 125 g, 1 cup of granulated sugar ≈ 200 g and 1 cup of water ≈ 237 g. 30 common ingredients are built in (flours, sugars, butter, oils, honey, rice, oats, cocoa, cornstarch and more), each with its grams-per-cup. Perfect for recipe apps, scaling and "metric vs cups" conversion, shopping lists and meal-prep tools. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. Distinct from general physical unit conversion, which has no ingredient densities.

api.oanor.com/cooking-api

Convert between INI configuration files and JSON, in both directions. The parse endpoint reads INI text — sections ([section]), nested sections ([database.replica]), key=value pairs, comments and repeated keys (arrays) — into a clean JSON object; the stringify endpoint turns a JSON object back into a properly formatted INI file. INI is the config format used by Git (.gitconfig), PHP (php.ini), systemd units, desktop entries, tox/setup.cfg, many CLI tools and Windows software. Perfect for editing config programmatically, migrating settings between formats, and reading config in environments that only speak JSON. Pure local computation — no key, no third-party service, instant; send large files via POST. Live, nothing stored. 3 endpoints. Complements the YAML, TOML, CSV and XML converters and is distinct from each.

api.oanor.com/ini-api

Live & historical foreign-exchange rates from the European Central Bank: latest rates, historical lookups, time-series and currency conversion across 30+ currencies.

api.oanor.com/currency-api