All MCP servers

Validate JSON against a JSON Schema offline, with a clear list of every structural error

Compare two JSON documents and apply RFC 6902 JSON Patch offline, with canonical output

Work with JSONC offline: strip comments and trailing commas, parse to JSON and locate errors

Parse, validate, convert and generate INI configuration offline: sections, comments, quotes

Read, create and validate iCalendar (.ics) data offline: parse events, build RFC 5545 files

Validate IBANs offline with the official length table and mod-97 checksum, country by country

Check a URL live: status, timing, redirect chains and security headers; private hosts blocked

HGNC gene nomenclature: search genes by symbol, alias or id, and read approved names

Classic hex dumps and byte stats offline: dump text, hex or base64 and convert between them

Identify hash types offline: match a hex or crypt string against known algorithms and lengths

NOAA GHCN station weather: daily and monthly summaries plus extremes for a station id

NCI Genomic Data Commons: TCGA and other cancer projects, with full project detail

See exactly how a number is stored as a float offline: bit layout, f32 rounding and neighbours

Formula 1 history from the Jolpica/Ergast archive: seasons, schedules, results and standings

Byte order and integer tools offline: swap endianness, read raw bytes and inspect two's complement

EBI Electron Microscopy Data Bank: search cryo-EM maps and read resolution and method

Dog photos from dog.ceo: a random image, every breed with sub-breeds and breed galleries

Live DNS lookups: A, AAAA, MX, TXT, NS, CNAME, SOA, CAA, SRV and PTR reverse lookups

CRC-32, CRC-32C, CRC-16 variants and Adler-32 offline, with checksum check values verified, keyless.

Exact combinatorics offline with BigInt: factorials, nCr, nPr, Fibonacci and permutations

cBioPortal cancer genomics: cancer types, gene lookup and public cancer studies

Cat facts and breed data from catfact.ninja: a random fact, paging and every breed

Validate Bitcoin addresses offline with real base58check and bech32/bech32m checksums

Brewery data from Open Brewery DB: name search, filter by city, state or type, full detail

Encode and decode base58 and base58check offline, with version bytes and checksums

Solar and lunar almanac offline: sunrise, sunset, twilight, sun position and moon phase

MobyGames (API key): search 300k+ games incl. retro, with credits, platforms and release dates.

Demoscene database: search 390k+ demos, intros, graphics and music, with group and credit data.