Seeded: the same schema, row count and seed always produce identical output. Coherent rows - email matches the name; city, state, postal, phone and currency match the country.
What it does
Generate deterministic fake data from a schema and a seed. Pick from 43 field types across eight categories: identity (name, email, username), contact (phone, avatar, password), location (country, city, state, postal, street, coordinates), commerce (company, job title, price, currency, product name, SKU), web (URL, slug, IPv4/IPv6, MAC, color, user agent), text (word, sentence, paragraph, headline, catchphrase), and numeric (integer, number, decimal, percentage, sequence, boolean), plus
UUIDUUIDA 128-bit identifier generated to be practically unique without coordination, most commonly in version-4 (fully random) form.
, date, pick-from-list, string, and index. Rows are coherent: an email matches the name on its row, and the city, state, postal code, phone format, and currency all match the row’s country. Seeded, so the same schema, row count, and seed always produce identical output - perfect for fixtures and tests. 100% client-side.How to use it
- Add fields: give each a name and pick a type from the grouped list (Identity, Contact, Location, Commerce, Web, Text, Numeric, Other).
- Set the type-specific options that appear (min/max, precision, length, charset, start/step, or pick options).
- Set the Rows count (1–500) and a Seed — hit New seed for a different random draw.
- The JSON renders live on the right, pinned while you scroll the schema.
- Copy it, or Download it as
mock-data.json.
Examples
Schema id: index, name: fullName, email: email, 3 rows, seed 1 → a 3-element array with sequential ids and coherent names/emails (each email derives from its row’s name).
Schema country, city, postal, phone, 5 rows → every row’s city, postal format, and phone format match its country.
Good to know
- Private: generation is local; data is synthetic, not real people.
- Seeded and deterministic (mulberry32 PRNG) - not cryptographically random; UUIDs are v4-shaped.
- Avatars are inline generated SVG identicons - no external requests.
- Related tools:
UUIDUUIDA 128-bit identifier generated to be practically unique without coordination, most commonly in version-4 (fully random) form.
Generator, JSON to TypeScript.