fejkdata/todo.md

Release checklist

Before v0.1.0

Data

Plan for the major data update. Research notes: ~/code/claude-handoffs/fejkdata/2026-09-16/.

Structure (proposal, pending review)

New costs ~23 ms and 58k allocations for today's 200 KB, one allocation per node, so real-world tables cannot ship as nested JSON objects. JSON says how a value is composed; TSV says which values exist.

• Add a table node: a category JSON naming a rows TSV beside it, whose header names the columns and whose rows are the draw. Options key (the column a path selects a row by), name (the column a path also selects by), weight (the column that skews the draw), parent (the table a column links to). {name} tokens read columns; a cell is a string node, so it may carry tokens. Index rows on first draw; at load prove only the header, the options and any cell token. A TSV nothing names is a load error.
• In a data file, refuse a choice whose items are templates with one identical field set, naming the TSV to write; an inline template is exempt, having no file. A choice of strings stays a choice.
• Convert misc.country, currency, language, httpstatus, mimetype, timezone, car and useragent to tables.
• Let a path select a row by key or by name, geo.SE.municipality[0180] and geo.SE.municipality[Stockholm], and descend to a linked table by name, geo.SE.region[Skåne län].street; a key or a linked table name may not equal a column name (load error). A name that matches several rows outside a pinned parent is an error listing the keys; inside one, region[IL].locality[Springfield] resolves. Brackets need quoting in zsh; : would not.
• Draw linked tables consistently within one render and draw group: the first table drawn pins its ancestors, and a descendant is drawn inside them.
• Keep country data under geo/<alpha2>/; a locale's address reads its country's tree by reference, and a locale's country table carries the localised names keyed by alpha2.
• Ship full registers as packs, each a Go module with its own embed.FS and a zip for --data-path; the default embed stays under ~1 MB per country and New under ~50 ms.
• Add DATA-LICENSES.md listing every dataset, its licence and its attribution, and a data-import/ directory of Python scripts that rebuild each TSV from its source, so a refresh is one command per dataset.
• Make every shipped category a record with its building blocks as columns (sv_SE.person → first, last, sex, done in step 3; misc.uuid → variant).
• Share the handle lists between email.local and username only if that is a clean win — a reference between shipped categories is a major once tagged.

Geo tree

Five linked tables per country, generic names so a template ports across countries; the README maps each to the native term.

Table	SE	US	Weight
region	län (21)	state and DC (50; Hawaii has no incorporated place)	population
municipality	kommun (290)	county with a shipped place	population
locality	postort, tätort population	place of 25,000+	population
postal-code	postnummer with street delivery	ZCTA of a shipped place	one; address ranges
street	gatunamn, top 10 per postort	street name, top 10 per place	segments; address ranges

• Shipped in step 2, README Data. geo.SE.address is a record over one consistent draw. Each region row carries its timezone, each locality its centroid.
• Let geo.SE.locality[Lund].address descend from a selected row into the template beside the family: the path step must reach a sibling category and the outer selector's pins seed every draw group of the render.
• Ship the fuller sets, every US place of 10,000 and more streets per locality, as packs; --min-population and --streets-per-locality on the scripts build them.
• Fill the 398 Swedish localities weighted 200 from SCB småorter before v0.1.0.
• Give the address records one column set across countries: region and municipality as building-block columns on geo.SE.address too, in step 6.
• v0.1.0 ships SE and US; then NO, DK, FI, NL, FR, AU, CA, ES, GB, DE.
• Revisit an application to Lantmäteriet for the exact street to postnummer pairing after v0.1.0; today a street goes to the nearest postal code centroid.

Builtins the data cannot express

• {date(from,to,'layout')} and {time('layout')} shipped in step 3; age() is rejected, README Decisions. Add a unix layout once something needs it.
• Derivations: {isin()} (Luhn over letters expanded to digits), {cusip()}, {aba()} (3-7-1 weights), {vin()} (position 9 over the whole; a sample taking the WMI, since the check sits mid-string).
• Samples: {base64url(n)} for JWT shapes; {btc()}, {eth()} after v0.1.0 (Base58Check and EIP-55 need sha256 and keccak).

Categories

Union of @faker-js/faker, Python Faker, gofakeit, Datafaker, Bogus, Mimesis, Chance and Ruby faker (research-libraries.md). What sets fejkdata apart, and what every issue tracker asks for: real values, frequency weights, and facts that agree across a record. No pop-culture catalogues. An LLM writes only non-factual lists (catchphrases, hacker phrases, product adjectives), never names, places, codes or ids. Shape: T = table, t = template, c = choice.

sv_SE (research-sources-se.md)

Category	Shape	Source	Licence
person first (female, male, generic), middle, last, weighted	T	SCB 2022 whole-population xlsx, Skatteverket 2026 surnames	CC0, "Källa: SCB"
person title, sex, birthdate, age, blood type weighted	t	geblod.nu distribution	facts
personnummer, samordningsnummer	t	Skatteverket test series: date + 238/239, Luhn	CC0
organisationsnummer by form, vat	t	Bolagsverket group digits, Luhn, SE…01	facts
company name patterns, legal form weighted	t	Bolagsverket registrations 2025	CC BY 2.5 SE
sni industry codes	T	SCB SNI 2025	"Källa: SCB"
ssyk occupations	T	SCB SSYK 2012	"Källa: SCB"
phone mobile, fixed per area code, E.164	T+t	PTS numbering plan 2024	facts
bankgiro, plusgiro, bankaccount clearing + Luhn/mod-11	T+t	Bankinfrastruktur CSV, Bankgirot rules	facts
licenseplate ABC 123, ABC 12A, blocked combinations	t	Transportstyrelsen	facts
car make, model weighted by registrations	T	Mobility Sweden 2025	cite
word noun, verb, adjective, adverb; sentence	T+t	SALDO	CC BY 4.0
date, time, month and weekday names, holiday	t+T	CLDR sv, lag 1989:253	Unicode
price 1 234,56 kr, email domains, url .se/.nu	t	curated	—
country localised names keyed by alpha2	T	CLDR sv territory names	Unicode
address	t	{/geo.SE…}	—

en_US (research-sources-world.md, part1–4)

Category	Shape	Source	Licence
person first by sex weighted, last weighted, middle, generic	T	SSA baby names, Census 2010 surnames	public domain
ssn, itin, ein valid ranges	t	SSA POMS, IRS	facts
company names, suffix, naics	t+T	SEC tickers for patterns, NAICS 2022	public domain
phone NANP with valid NPA/NXX	t	NANPA rules	facts
routing ABA with check, bankaccount	t	Fed prefix ranges	facts
licenseplate per state	T	hand-authored patterns	facts
car make, model	T	NHTSA vPIC	public domain
word, sentence, paragraph	T+t	Moby POS or WordNet	public domain / WordNet
date, time, names, holiday	t+T	CLDR en	Unicode
price $1,234.56, email, url, address	t	curated, {/geo.US…}	—

misc (locale-neutral)

Category	Shape	Source	Licence
country name, alpha2, alpha3, numeric, calling code, TLD, capital, currency, flag, languages	T	datasets/country-codes	PDDL
currency code, numeric, name, symbol, decimals	T	ISO 4217 list-one, CLDR symbols	free, Unicode
language ISO 639-1/2	T	LoC	public domain
timezone zone, country, offset	T	tzdb zone1970.tab	public domain
mimetype type, extensions	T	IANA + mime-db	CC0, MIT
httpstatus, httpmethod, port, tld, protocol, loglevel	T/c	IANA	CC0
useragent per browser	T	top-user-agents	MIT
ip v4 documentation ranges, private, CIDR; ipv6 2001:db8::/32; mac locally administered	t	RFC 5737, 1918, 9637	facts
creditcard per network: IIN, length, CVV, expiry	T+t	network rules, {luhn()}	facts
bic, iban (exists), isin, cusip	t	structure rules	facts
ean, upc, gtin, isbn, issn, imei, asin, sku	t	check-digit rules, GS1 demo prefix 952	facts
product name, adjective, material, department, garmentsize	T/c	LLM-written lists	—
airport IATA, ICAO, country, municipality; airline; aircraft; flight, seat, pnr	T+t	OurAirports, Wikidata	public domain, CC0
element, unit, planet	T	PubChem, BIPM, NASA	public domain, CC BY 4.0
animal by class, plant	T	Wikidata	CC0
bloodtype weighted (global)	c	AABB	facts
color named, hex, rgb, hsl, cmyk	T+t	CSS Color 4, XKCD	W3C, CC0
programminglanguage, os, database column/type/engine, fileext, semver (exists)	T/c	Linguist, curated	MIT
commit message, branch, sha	t	LLM-written, {hex(40)}	—
password, hash, jwt, slug, hostname, avatar, placeholderimage	t	shapes	—
book title, author from Gutenberg; genre; instrument; dish, ingredient	T	Gutenberg catalog, MusicBrainz, USDA	CC0
lorem, hacker, hipster, catchphrase, buzzword, quote	T/c	lorem ipsum, LLM-written	—
coordinate (exists), direction, continent, emoji (exists), uuid, ulid, objectid	c/t	—	—

Later locales: nb_NO, da_DK, fi_FI, de_DE, en_GB, nl_NL, fr_FR, es_ES with person, address, phone, national id, company and date names each.

Order of work

1. Table node, key and name selection, parent links, consistent draws, the choice-of-rows fence, DATA-LICENSES.md, data-import/ — done.
2. geo/SE and geo/US, and address in both locales on top of them — done.
3. Weighted person names and valid ids in both locales; date() — done. Middle names wait for a draw group that shares its family's pins, so a second name is drawn under the same sex.
4. misc conversions and the new misc tables.
5. The remaining locale categories: company, phone, finance, vehicle, words.
6. Records with building-block columns across the shipped set; shape re-pin.

Release

• CLI without Go — investigate prebuilt binaries: GoReleaser attaching them to the Gitea release the tag workflow publishes, a container image, Homebrew and Scoop. A checkout build prints devel for --version; the binaries carry the stamped tag.
• Homepage — a simple page for fejkdata with an in-browser generator: the library compiled to WebAssembly, so visitors generate as much data as they like in their own browser.