Quick start¶

Synth is a pure data provider: it never connects to a database, never runs INSERT, never reads DDL from a server. You hand it a plain Go struct; it hands you coherent records — in memory, to a file, or streamed. Loading is a separate tool's job.

package main

import (
    "time"

    "github.com/bakhod1r/synth"
    "github.com/google/uuid"
)

type User struct {
    ID        uuid.UUID `synth:"pk"`
    FirstName string
    Email     string `synth:"email,from=FirstName"` // derived from the name
    Phone     string
    Country   string
    Region    string
    City      string
    Postcode  string // stays coherent with Country/Region/City
    Card      string `synth:"card"` // Luhn-valid HUMO/UZCARD
    CreatedAt time.Time
}

func main() {
    // Tags are optional — untagged fields are inferred from name and type.
    users := synth.Make[User](10_000, synth.WithSeed(42), synth.WithLocale("uz_UZ"))

    synth.WriteCSV("users.csv", users)                       // to a file
    synth.Stream[User](1_000_000).ToJSONL("users.jsonl")     // constant memory
}

Referential integrity¶

users  := synth.Make[User](10_000, synth.WithSeed(1))
orders := synth.Make[Order](500_000, synth.Ref(users, "UserID")) // every FK is real

Temporal causality¶

Timestamps respect the order events can happen in — a record's lifecycle stays consistent instead of scattering random points in a range.

type Order struct {
    CreatedAt   time.Time
    PaidAt      time.Time `synth:"time,after=CreatedAt,gap=1h..48h"`
    ShippedAt   time.Time `synth:"time,after=PaidAt,gap=1h..72h"`
    DeliveredAt time.Time `synth:"time,after=ShippedAt,gap=1h..120h"`
}
// CreatedAt < PaidAt < ShippedAt < DeliveredAt, always.

Fluent single values¶

For a one-off value rather than a dataset:

g := synth.New(synth.Config{Seed: 42, Locale: "uz_UZ"})
g.Name()      // "Azizbek Karimov"
g.Phone()     // "+998901234567"
g.Card()      // Luhn-valid
g.Amount(1000, 500000)

Without Go¶

Describe the data in YAML and run the CLI — see CLI and YAML specs.

synth gen -s users.yaml -o users.csv -n 100000 --seed 42