Western and Orthodox Easter for any year from 1583 with Ash Wednesday, Palm Sunday, Good Friday, Ascension, Pentecost and Corpus Christi dates

Julian date, modified Julian date, day number, Greenwich mean sidereal time and local sidereal time for a timestamp and longitude

Airport lookup from OurAirports by ICAO, IATA or local code, by name or city, or the nearest airports to coordinates - type, elevation, scheduled service and links

Marine species sightings from OBIS by scientific name - coordinates, depth, date, country, dataset, basis of record and taxonomic family

Pilot reports near an airport - turbulence and icing intensity, flight level, aircraft type, cloud, wind and temperature, with counts of significant reports

Bitcoin mining profit from hashrate, power, electricity price, BTC price and difficulty: daily BTC, margin, breakeven price and rate, and hardware payback.

Look up legal entities in the GLEIF LEI index by company name or LEI - status, jurisdiction, legal form, addresses, registration and renewal dates

Search French companies by name, SIREN or SIRET - status, creation date, activity code, size, head office address, establishments and officers

Balance a chemical equation with the smallest whole-number coefficients, with an atom-by-atom check and the mass balance for reactants and products

ChEBI chemical entities by name - definition, formula, mass, monoisotopic mass, charge, SMILES, InChIKey and curation stars from EMBL-EBI

Find NCBI GEO gene expression series by topic - accession, title, summary, organism, study type, sample count, platform and linked PubMed IDs

Molar mass of a chemical formula with brackets and hydrates - g/mol, Hill formula, atom counts, mass percent per element and moles from a sample in grams

Convert XML to JSON with attributes as @keys, repeated elements as arrays, CDATA and entities handled, using a parser that rejects DOCTYPE and entities

Find the nearest active NOAA weather stations to a coordinate - GHCN station ID, name, distance, record start and latest data date, ready for history queries

Credit utilization calculator - overall and per-card utilization plus paydown needed for a target percent

Render Markdown to escaped, safe HTML with heading anchors, links, images and lists, plus the heading outline, link list, word count and reading time

Chemical element facts by symbol, name or atomic number - weight, group, electron configuration, electronegativity, melting and boiling point, density

Chicago reported crimes by type, ward and arrest status over a chosen number of days - incident counts by type and the most recent records with locations

Historical daily or monthly weather for a NOAA station - high, low and mean temperature, rain, snow, wettest day, hottest day and heating and cooling degree days

Profile CSV text - detected delimiter, per-column type, nulls, unique counts, min, max, mean, median, top values, duplicate rows and ragged rows