MRTD Quick Start¶

MRTD is a tabular format.

The first row is the header. Every later row is data. Cells are separated by whitespace rather than commas.

Basic example¶

name:string age:int active:bool
Ada 32 true
"Rena Holm" 29 false

Header cells¶

Each header cell is either:

a field name
or a field name with a type annotation like name:string

The current core draft supports only these scalar types:

int
float
bool
string

Quoted names and values¶

Identifiers can be written without quotes:

name city
Ada Oslo

Anything that is not a valid identifier should be quoted:

"full name":string city:string
"Rena Holm" "Bergen sentrum"

Multiline rows¶

Rows can be wrapped in round brackets when they need to span multiple lines:

name:string note:string score:float
( "Rena Holm"
  "line wrapped"
  13.5 )

Profiles¶

The MRTD core does not include suffix extensions. If an implementation supports extra suffixes, they should be exposed through named profiles rather than being accepted silently in core mode.

The current profile experiment is extended-scalars. That profile allows examples such as:

when bonus
"2026-04-03"dt 3k

Profile activation is intended to be composable. An implementation may enable more than one named profile at once.

Implementation examples¶

Makrell#¶

var rows = MrtdTyped.ReadRecords<Person>(
    """
    name:string age:int active:bool
    Ada 32 true
    Ben 41 false
    """);

var doc = MrtdParser.ParseSource(
    """
    when bonus
    "2026-04-03"dt 3k
    """,
    new MrtdParseOptions
    {
        Profiles = new HashSet<string>(StringComparer.Ordinal)
        {
            MrtdProfiles.ExtendedScalars,
        },
    });

MakrellPy¶

from makrell.mrtd import read_records

rows = read_records("""
name:string age:int active:bool
Ada 32 true
Ben 41 false
""")

doc = parse_src("""
when bonus
"2026-04-03"dt 3k
""", profiles=("extended-scalars",))

MakrellTS¶

import { parseMrtd, readMrtdRecords } from "makrellts";

const rows = readMrtdRecords(`
name:string age:int active:bool
Ada 32 true
Ben 41 false
`);

const doc = parseMrtd(`
when bonus
"2026-04-03"dt 3k
`, { profiles: ["extended-scalars"] });

Where to go next¶

the current draft spec in specs/mrtd-spec.md
Implementation Matrix
the MakrellPy, MakrellTS, and Makrell# implementation sections