This package provides a header-only library of small, fast, portable C99 primitives for converting external text and bytes into native values and back: correctly rounded number parsing (from fast_float', through its C port ffc.h'), shortest round-trip number formatting (from Ryu'), ISO 8601 dates and timestamps, booleans, universally unique identifiers (UUIDs), hexadecimal and Base64, XXH3 hashing (from xxHash'), half-precision floats, endian helpers and UTF-8 validation. Other packages use it through LinkingTo alone; the R functions exist to test, benchmark and demonstrate the C layer.