Are the credit card numbers real?

They are valid and they are not real. Each one carries a correct Luhn check digit, so a payment library will accept its format, and each is built on one of the four published test BINs rather than a live issuing range, so it cannot coincide with a card somebody holds. They will not authorise a payment anywhere.

Will the same seed really give me the same data next year?

Yes. The generator is a published algorithm with a fixed reference implementation, not a browser API whose behaviour can change, and this page is tested against output transcribed from that reference. Nothing reads the clock: date ranges are literal values in the schema. Keep the schema JSON and the seed it contains and the rows come back exactly.

Why did adding a column change nothing else?

Because each field draws from its own stream, keyed on the seed and the field name. It is deliberate: a fixture that reshuffles every time you extend the schema is one you cannot keep in a repository. The same property means raising the row count leaves the earlier rows alone.

I renamed a field and its data changed.

That follows from the same design — the field name is half of its stream key. If you want to keep the values, rename the column downstream instead, or accept the new draw. There is no way to have both stable-under-rename and stable-under-reorder without a hidden identifier the schema file would then have to carry.

Can I use this to generate a password or an API key?

No. Everything here comes from a seeded pseudo-random generator, which is predictable by design and is the reason the output is reproducible. A secret has to come from the platform’s cryptographic source. Use a dedicated token generator for that.

How do I make the email match the name?

Add a template field and write the other columns in double braces — something like {{first_name}}.{{last_name}}@example.com — then set the case transform to lower. The fields are generated in dependency order, so the template can name a column that appears after it in the list.

How many rows can it produce?

Ten thousand, across up to forty fields. Generation is fast enough to stay on the main thread at that size; what actually gets uncomfortable is the resulting text, which is why the pane shows a truncated preview while copy and download take the whole thing.

Does any of this leave my browser?

No. The generator, the corpus of names and every output format run as JavaScript on the page. There is no server call, and nothing you type into the schema is sent anywhere.

Mock data generator

Generate mock data that passes validation: Luhn-correct cards, mod-97 IBANs, real UUIDs. Seeded and reproducible, as JSON, CSV, NDJSON or SQL.

Seed

RowsPreset

Fields8 of 40

NameTypeVersionFromStep (ms)Nulls

NameTypeNulls

NameTypePatternCaseNulls

NameTypeFormNulls

NameTypeFromToOutputNulls

NameTypeTrue rateNulls

Schema

Output100 rows · 28086 characters

[
  {
    "id": "018cc251-f400-79a7-abdf-9623646f1963",
    "first_name": "Ruby",
    "last_name": "Long",
    "email": "[email protected]",
    "country": "IE",
    "created_at": "2024-04-13T08:13:34Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc251-f7e8-7727-8c38-6095cbcabdb9",
    "first_name": "Ellen",
    "last_name": "Hoffman",
    "email": "[email protected]",
    "country": "US",
    "created_at": "2024-06-28T10:45:21Z",
    "last_seen_at": "2024-10-31T16:44:09Z",
    "is_active": false
  },
  {
    "id": "018cc251-fbd0-7056-ad40-e80a775668cc",
    "first_name": "Keith",
    "last_name": "Hudson",
    "email": "[email protected]",
    "country": "AR",
    "created_at": "2025-08-11T01:04:04Z",
    "last_seen_at": "2025-09-19T15:18:41Z",
    "is_active": true
  },
  {
    "id": "018cc251-ffb8-74a1-b4c8-83cc6bd2ae90",
    "first_name": "Thomas",
    "last_name": "Moore",
    "email": "[email protected]",
    "country": "BE",
    "created_at": "2025-02-21T16:27:55Z",
    "last_seen_at": "2025-04-28T03:30:59Z",
    "is_active": true
  },
  {
    "id": "018cc252-03a0-7309-8795-f9f277a8f8c0",
    "first_name": "Benjamin",
    "last_name": "Austin",
    "email": "[email protected]",
    "country": "MX",
    "created_at": "2024-06-15T11:04:56Z",
    "last_seen_at": "2025-06-30T22:00:26Z",
    "is_active": true
  },
  {
    "id": "018cc252-0788-7658-937d-58b138c92232",
    "first_name": "Barbara",
    "last_name": "Flores",
    "email": "[email protected]",
    "country": "GR",
    "created_at": "2024-04-17T19:41:08Z",
    "last_seen_at": "2025-01-13T23:55:46Z",
    "is_active": true
  },
  {
    "id": "018cc252-0b70-7c3a-96ae-719ee90a05af",
    "first_name": "Allen",
    "last_name": "Vazquez",
    "email": "[email protected]",
    "country": "NG",
    "created_at": "2024-09-18T13:23:49Z",
    "last_seen_at": "2026-05-04T06:32:51Z",
    "is_active": false
  },
  {
    "id": "018cc252-0f58-7dfd-8623-52572f04ce20",
    "first_name": "Harry",
    "last_name": "Nichols",
    "email": "[email protected]",
    "country": "SG",
    "created_at": "2026-06-26T14:48:47Z",
    "last_seen_at": "2026-06-30T12:56:13Z",
    "is_active": false
  },
  {
    "id": "018cc252-1340-738f-b536-279444cb4512",
    "first_name": "Elaine",
    "last_name": "Wagner",
    "email": "[email protected]",
    "country": "UA",
    "created_at": "2025-05-09T14:48:44Z",
    "last_seen_at": "2026-05-19T14:58:47Z",
    "is_active": true
  },
  {
    "id": "018cc252-1728-7d96-8856-b87ee9d904e9",
    "first_name": "Fred",
    "last_name": "Fisher",
    "email": "[email protected]",
    "country": "JP",
    "created_at": "2025-11-25T05:27:13Z",
    "last_seen_at": "2026-04-04T05:36:09Z",
    "is_active": true
  },
  {
    "id": "018cc252-1b10-7baa-a79b-9567cf1366fd",
    "first_name": "Lois",
    "last_name": "Nelson",
    "email": "[email protected]",
    "country": "FR",
    "created_at": "2025-05-08T16:32:25Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-1ef8-7c8c-b859-cea655faef9c",
    "first_name": "Mark",
    "last_name": "Cunningham",
    "email": "[email protected]",
    "country": "FI",
    "created_at": "2026-02-21T11:09:02Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-22e0-77bf-bc1c-40120a5b29c4",
    "first_name": "Anne",
    "last_name": "Flores",
    "email": "[email protected]",
    "country": "KR",
    "created_at": "2025-08-02T22:55:20Z",
    "last_seen_at": "2025-10-27T03:27:52Z",
    "is_active": true
  },
  {
    "id": "018cc252-26c8-7220-9453-1804e8ce88c4",
    "first_name": "Arthur",
    "last_name": "Crawford",
    "email": "[email protected]",
    "country": "PL",
    "created_at": "2025-02-26T04:55:03Z",
    "last_seen_at": "2025-07-25T07:05:17Z",
    "is_active": true
  },
  {
    "id": "018cc252-2ab0-75a8-8a2b-28833306b87c",
    "first_name": "Ronald",
    "last_name": "Hansen",
    "email": "[email protected]",
    "country": "KR",
    "created_at": "2025-03-09T06:31:44Z",
    "last_seen_at": "2026-01-04T03:11:24Z",
    "is_active": true
  },
  {
    "id": "018cc252-2e98-7c38-93e2-9f80d039eb75",
    "first_name": "Donna",
    "last_name": "Porter",
    "email": "[email protected]",
    "country": "IE",
    "created_at": "2026-01-12T06:55:22Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-3280-77a0-8152-8f5a9584a581",
    "first_name": "Carol",
    "last_name": "Wells",
    "email": "[email protected]",
    "country": "PL",
    "created_at": "2025-07-20T23:09:02Z",
    "last_seen_at": "2026-01-24T23:04:38Z",
    "is_active": true
  },
  {
    "id": "018cc252-3668-7208-8bbe-619dada6b7e0",
    "first_name": "Sheila",
    "last_name": "Lee",
    "email": "[email protected]",
    "country": "PT",
    "created_at": "2025-01-05T20:09:52Z",
    "last_seen_at": "2025-04-08T12:02:09Z",
    "is_active": false
  },
  {
    "id": "018cc252-3a50-7b11-9261-0c17e909f6fb",
    "first_name": "Jack",
    "last_name": "Evans",
    "email": "[email protected]",
    "country": "KE",
    "created_at": "2025-12-29T14:31:00Z",
    "last_seen_at": "2026-03-28T14:30:43Z",
    "is_active": true
  },
  {
    "id": "018cc252-3e38-7f22-8cc7-0dd649d26379",
    "first_name": "Randy",
    "last_name": "Harris",
    "email": "[email protected]",
    "country": "GB",
    "created_at": "2026-06-26T19:25:04Z",
    "last_seen_at": "2026-06-30T08:39:51Z",
    "is_active": true
  },
  {
    "id": "018cc252-4220-7e86-8dae-b25b4f837713",
    "first_name": "Josephine",
    "last_name": "Castro",
    "email": "[email protected]",
    "country": "DK",
    "created_at": "2024-02-07T22:33:55Z",
    "last_seen_at": "2026-02-23T13:56:30Z",
    "is_active": true
  },
  {
    "id": "018cc252-4608-7120-abd5-535883ca01b9",
    "first_name": "Edith",
    "last_name": "Graham",
    "email": "[email protected]",
    "country": "CN",
    "created_at": "2024-04-29T08:59:26Z",
    "last_seen_at": "2024-06-17T10:20:45Z",
    "is_active": true
  },
  {
    "id": "018cc252-49f0-77f7-9bf9-17e87b0a09c6",
    "first_name": "Tracy",
    "last_name": "Willis",
    "email": "[email protected]",
    "country": "PT",
    "created_at": "2024-03-21T07:42:06Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-4dd8-75c8-8b04-1e0fb891e435",
    "first_name": "Irene",
    "last_name": "Larson",
    "email": "[email protected]",
    "country": "AT",
    "created_at": "2025-06-04T15:01:38Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-51c0-7be0-a6ca-12bc704a2b3f",
    "first_name": "Betty",
    "last_name": "Morrison",
    "email": "[email protected]",
    "country": "ID",
    "created_at": "2025-11-11T21:56:19Z",
    "last_seen_at": "2026-03-29T03:33:49Z",
    "is_active": true
  },
  {
    "id": "018cc252-55a8-736d-a7b2-8bec744ecf74",
    "first_name": "Kevin",
    "last_name": "Cox",
    "email": "[email protected]",
    "country": "GR",
    "created_at": "2025-10-06T23:28:21Z",
    "last_seen_at": null,
    "is_active": false
  },
  {
    "id": "018cc252-5990-73ca-a2d3-89bf2b8eb5f6",
    "first_name": "Sean",
    "last_name": "Carr",
    "email": "[email protected]",
    "country": "KR",
    "created_at": "2026-02-19T23:27:53Z",
    "last_seen_at": "2026-03-02T22:16:30Z",
    "is_active": true
  },
  {
    "id": "018cc252-5d78-79e2-bd4d-d8b6867867dc",
    "first_name": "Heather",
    "last_name": "Ferguson",
    "email": "[email protected]",
    "country": "IL",
    "created_at": "2024-07-07T01:39:16Z",
    "last_seen_at": "2025-09-21T19:17:00Z",
    "is_active": false
  },
  {
    "id": "018cc252-6160-78f8-a9af-d73b74581b86",
    "first_name": "Rose",
    "last_name": "Chen",
    "email": "[email protected]",
    "country": "DE",
    "created_at": "2024-09-07T16:16:48Z",
    "last_seen_at": "2024-10-02T08:29:39Z",
    "is_active": true
  },
  {
    "id": "018cc252-6548-71f0-ab4f-c824fd842a67",
    "first_name": "Maria",
    "last_name": "Brooks",
    "email": "[email protected]",
    "country": "FR",
    "created_at": "2024-06-29T06:22:30Z",
    "last_seen_at": "2025-12-22T00:38:13Z",
    "is_active": true
  },
  {
    "id": "018cc252-6930-7067-b516-480051493ec0",
    "first_name": "Donna",
    "last_name": "Hamilton",
    "email": "[email protected]",
    "country": "IE",
    "created_at": "2024-09-01T09:09:40Z",
    "last_seen_at": "2025-03-29T23:26:22Z",
    "is_active": false
  },
  {
    "id": "018cc252-6d18-7de1-bae1-21dc471405fa",
    "first_name": "Rachel",
    "last_name": "Wagner",
    "email": "[email protected]",
    "country": "IE",
    "created_at": "2026-05-31T02:06:02Z",
    "last_seen_at": "2026-06-17T16:37:27Z",
    "is_active": false
  },
  {
    "id": "018cc252-7100-752d-bc4e-c4e5bd755743",
    "first_name": "Philip",
    "last_name": "Jones",
    "email": "[email protected]",
    "country": "NO",
    "created_at": "2024-10-21T12:22:35Z",
    "last_seen_at": "2025-02-15T07:00:10Z",
    "is_active": true
  },
  {
    "id": "018cc252-74e8-7b4d-b9cf-4e8e03d1e269",
    "first_name": "Bonnie",
    "last_name": "Carter",
    "email": "[email protected]",
    "country": "PT",
    "created_at": "2026-05-28T06:16:25Z",
    "last_seen_at": "2026-06-26T21:36:12Z",
    "is_active": true
  },
  {
    "id": "018cc252-78d0-708b-a96f-d9f474e95238",
    "first_name": "Douglas",
    "last_name": "Evans",
    "email": "[email protected]",
    "country": "NG",
    "created_at": "2024-02-18T20:36:33Z",
    "last_seen_at": "2024-10-31T01:37:50Z",
    "is_active": true
  },
  {
    "id": "018cc252-7cb8-7865-96fa-e9681611dbed",
    "first_name": "Theresa",
    "last_name": "Larson",
    "email": "[email protected]",
    "country": "NZ",
    "created_at": "2024-11-21T08:57:18Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-80a0-7eca-80cd-7159faf3467f",
    "first_name": "Gladys",
    "last_name": "Reyes",
    "email": "[email protected]",
    "country": "NG",
    "created_at": "2024-04-27T11:34:46Z",
    "last_seen_at": "2026-03-09T18:39:31Z",
    "is_active": true
  },
  {
    "id": "018cc252-8488-76b2-9271-dabf0da27b4f",
    "first_name": "Bonnie",
    "last_name": "Cook",
    "email": "[email protected]",
    "country": "AT",
    "created_at": "2024-01-13T17:42:35Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-8870-70d0-ab33-72cd838e6603",
    "first_name": "Diane",
    "last_name": "Wells",
    "email": "[email protected]",
    "country": "NZ",
    "created_at": "2024-05-02T11:22:23Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-8c58-725c-980d-f206b971497b",
    "first_name": "Gloria",
    "last_name": "Woods",
    "email": "[email protected]",
    "country": "IT",
    "created_at": "2025-06-27T01:56:54Z",
    "last_seen_at": "2025-09-04T17:13:00Z",
    "is_active": true
  },
  {
    "id": "018cc252-9040-786d-90d1-5c9bae512dbf",
    "first_name": "Alan",
    "last_name": "Rodriguez",
    "email": "[email protected]",
    "country": "DK",
    "created_at": "2026-03-29T17:48:08Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-9428-7b58-8dde-508b603b97d8",
    "first_name": "Leonard",
    "last_name": "Jones",
    "email": "[email protected]",
    "country": "MX",
    "created_at": "2026-02-06T22:38:18Z",
    "last_seen_at": "2026-04-27T00:46:32Z",
    "is_active": true
  },
  {
    "id": "018cc252-9810-7c69-8024-23852691d72c",
    "first_name": "Maria",
    "last_name": "Davis",
    "email": "[email protected]",
    "country": "JP",
    "created_at": "2025-03-30T14:01:05Z",
    "last_seen_at": "2025-04-24T10:25:01Z",
    "is_active": true
  },
  {
    "id": "018cc252-9bf8-7e3a-a37a-06b1a661a0dc",
    "first_name": "Carl",
    "last_name": "Duncan",
    "email": "[email protected]",
    "country": "KE",
    "created_at": "2026-03-30T06:02:52Z",
    "last_seen_at": "2026-05-16T00:15:55Z",
    "is_active": false
  },
  {
    "id": "018cc252-9fe0-7a01-8a38-5d3e36f9eca3",
    "first_name": "Phillip",
    "last_name": "Harrison",
    "email": "[email protected]",
    "country": "DK",
    "created_at": "2024-07-12T01:56:26Z",
    "last_seen_at": "2026-05-28T21:32:17Z",
    "is_active": true
  },
  {
    "id": "018cc252-a3c8-7977-a212-1c82b978ccbe",
    "first_name": "Kim",
    "last_name": "Franklin",
    "email": "[email protected]",
    "country": "KE",
    "created_at": "2024-09-23T15:16:03Z",
    "last_seen_at": "2025-08-20T03:29:07Z",
    "is_active": true
  },
  {
    "id": "018cc252-a7b0-78f6-bb2a-d194bc638e71",
    "first_name": "Patrick",
    "last_name": "Coleman",
    "email": "[email protected]",
    "country": "ID",
    "created_at": "2025-01-06T09:04:26Z",
    "last_seen_at": "2025-07-21T22:36:07Z",
    "is_active": true
  },
  {
    "id": "018cc252-ab98-7b5b-8f5c-8b6a21b71208",
    "first_name": "Harry",
    "last_name": "Martin",
    "email": "[email protected]",
    "country": "ES",
    "created_at": "2026-02-21T17:42:10Z",
    "last_seen_at": "2026-05-16T20:52:12Z",
    "is_active": true
  },
  {
    "id": "018cc252-af80-7504-8719-59c6e3efd9c3",
    "first_name": "Carlos",
    "last_name": "Gibson",
    "email": "[email protected]",
    "country": "ZA",
    "created_at": "2024-01-14T06:39:34Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-b368-7525-9a9c-a09c2f8c2c8b",
    "first_name": "Jean",
    "last_name": "Morales",
    "email": "[email protected]",
    "country": "CA",
    "created_at": "2025-06-05T13:13:54Z",
    "last_seen_at": "2025-07-18T07:30:36Z",
    "is_active": true
  },
  {
    "id": "018cc252-b750-76bd-81cc-42435c3231bd",
    "first_name": "Ernest",
    "last_name": "Cooper",
    "email": "[email protected]",
    "country": "FR",
    "created_at": "2026-06-30T05:15:30Z",
    "last_seen_at": "2026-06-30T22:07:31Z",
    "is_active": true
  },
  {
    "id": "018cc252-bb38-7a65-8fdd-29417173ce08",
    "first_name": "John",
    "last_name": "Wallace",
    "email": "[email protected]",
    "country": "GR",
    "created_at": "2024-01-01T11:53:11Z",
    "last_seen_at": "2025-05-13T01:10:51Z",
    "is_active": false
  },
  {
    "id": "018cc252-bf20-7253-a075-e01c6d997ffd",
    "first_name": "Lee",
    "last_name": "Brooks",
    "email": "[email protected]",
    "country": "AU",
    "created_at": "2024-03-20T07:03:24Z",
    "last_seen_at": "2025-04-29T10:30:14Z",
    "is_active": true
  },
  {
    "id": "018cc252-c308-7709-a61e-916f4cb44f86",
    "first_name": "Antonio",
    "last_name": "Evans",
    "email": "[email protected]",
    "country": "JP",
    "created_at": "2025-09-17T01:49:49Z",
    "last_seen_at": "2026-04-27T19:54:08Z",
    "is_active": true
  },
  {
    "id": "018cc252-c6f0-7095-be95-c60913b0062d",
    "first_name": "Jose",
    "last_name": "Porter",
    "email": "[email protected]",
    "country": "ZA",
    "created_at": "2024-06-01T00:33:54Z",
    "last_seen_at": "2024-09-30T08:59:58Z",
    "is_active": false
  },
  {
    "id": "018cc252-cad8-7565-b5d8-117f4a6fb217",
    "first_name": "Eric",
    "last_name": "Ward",
    "email": "[email protected]",
    "country": "TR",
    "created_at": "2024-03-06T08:01:45Z",
    "last_seen_at": "2024-10-07T12:38:03Z",
    "is_active": true
  },
  {
    "id": "018cc252-cec0-79ae-adaa-96058dd4aabe",
    "first_name": "Marjorie",
    "last_name": "Cox",
    "email": "[email protected]",
    "country": "NG",
    "created_at": "2026-06-08T11:01:04Z",
    "last_seen_at": "2026-06-20T16:41:37Z",
    "is_active": true
  },
  {
    "id": "018cc252-d2a8-7d31-bab8-63bfaa7342bd",
    "first_name": "Bryan",
    "last_name": "Pena",
    "email": "[email protected]",
    "country": "IT",
    "created_at": "2024-01-06T14:25:41Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-d690-7e1b-a275-f48a8c1ccbf6",
    "first_name": "Catherine",
    "last_name": "Munoz",
    "email": "[email protected]",
    "country": "AU",
    "created_at": "2026-05-30T07:29:25Z",
    "last_seen_at": "2026-06-23T08:23:39Z",
    "is_active": true
  },
  {
    "id": "018cc252-da78-7c22-9180-f137d46ec702",
    "first_name": "Joyce",
    "last_name": "Jordan",
    "email": "[email protected]",
    "country": "TR",
    "created_at": "2025-01-13T19:52:26Z",
    "last_seen_at": null,
    "is_active": true
  },
  {
    "id": "018cc252-de60-7bc5-907f-8eebca9226bf",
    "first_name": "Jennifer",
    "last_name": "Riley",
    "email": "[email protected]",
    "country": "AT",
    "created_at": "2026-02-21T06:27:48Z",
    "last_seen_at": "2026-04-30T10:23:57Z",
    "is_active": true
  },
  {
    "id": "018cc252-e248-7464-86b7-54ee11fc6051",
    "first_name": "Amanda",
    "last_name": "Daniels",
    "email": "[email protected]",
    "country": "IL",
    "created_at": "2025-04-29T02:18:30Z",
    "last_seen_at": "2026-04-17T18:37:07Z",
    "is_active": false
  },
  {
    "id": "018cc252-e630-7bf3-ab8d-a72175e7c3fb",
    "first_name": "Laura",
    "last_name": "Alvarado",
    "email": "[email protected]",
    "country": "PT",
    "created_at": "2024-08-26T17:26:51Z",
    "last_seen_at": "2025-09-16T12:46:07Z",
    "is_active": true
  },
  {
    "id": "018cc252-ea18-74fb-955a-5d6d42ed1760",
    "first_name": "Andrea",
    "last_name": "Turner",
    "email": "[email protected]",
    "country": "CA",
    "created_at": "2024-07-13T08:04:19Z",
    "last_seen_at": "2025-01-08T17:24:13Z",
    "is_active": true
  },
  {
    "id": "018cc252-ee00-7216-953a-2094b3402b1e",
    "first_name": "Margaret",
    "last_name": "Jackson",
    "email": "[email protected]",
    "country": "NZ",
    "created_at": "2025-07-14T00:05:54Z",
    "last_seen_at": "2026-05-05T09:44:04Z",
    "is_active": true
  },
  {
    "id": "018cc252-f1e8-7262-91aa-5818265220ca",
    "first_name": "Rose",
    "last_name": "Johnson",
    "email": "[email protected]",
    "country": "KR",
    "created_at": "2024-07-18T02:49:21Z",
    "last_seen_at": "2025-04-18T08:52:53Z",
    "is_active": true
  },
  {
    "id": "018cc252-f5d0-72f1-ba49-a52514f881dd",
    "first_name": "Fred",
    "last_name": "George",
    "email": "[email protected]",
    "country": "PL",
    "created_at": "2025-10-26T23:11:53Z",
    "last_seen_at": "2025-11-05T21:15:27Z",
    "is_active": true
  },
  {
    "id": "018cc252-f9b8-7173-b05d-540124a4fc47",
    "first_name": "Sara",
    "last_name": "Greene",
    "email": "[email protected]",
    "country": "PT",
    "created_at": "2026-04-26T10:11:22Z",
    "last_seen_at": "2026-05-07T04:01:08Z",
    "is_active": true
  },
  {
    "id": "018cc252-fda0-7ed5-a24a-3f179c69fc3c",
    "first_name": "Jesse",
    "last_name": "Bennett",
    "email": "[email protected]",
    "country": "SG",
    "created_at": "2025-10-08T16:19:51Z",
    "last_seen_at": "2026-03-04T05:50:50Z",
    "is_active": true
  },
  {
    "id": "018cc253-0188-74dd-a728-ed228fc827ac",
    "first_name": "Louise",
    "last_name": "Santos",
    "email": "[email protected]",
    "country": "FI",
    "created_at": "2026-05-29T18:38:35Z",
    "last_seen_at": "2026-06-01T15:33:29Z",
    "is_active": true
  },
  {
    "id": "018cc253-0570-7408-b582-07fbebeacbbf",
    "first_name": "Scott",
    "last_name": "Grant",
    "email": "[email protected]",
    "country": "NZ",
    "created_at": "2024-02-11T17:35:11Z",
    "last_seen_at": "2025-08-06T23:23:49Z",
    "is_active": true
  },
  {
    "id": "018cc253-0958-7c12-b38e-edc7af958916",
    "first_name": "Judy",
    "last_n

Showing the first 20000 of 28086 characters. Copy and download take all of it.

FormatIndentedTableDialect

Mail goes to example.com, phone numbers to the 555-0100 block, addresses to the documentation networks and card numbers to published test BINs — every default here is a range a standard reserves, so nothing generated can belong to a real person.

Data that passes your validators

The usual complaint about generated test data is not that it looks fake. It is that it fails. A card number that no payment library will accept, an IBAN that a banking form rejects, an ISBN a barcode reader will not read, a UUID whose version nibble is whatever the random bytes happened to be. You end up hand-editing the fixture, and at that point the generator has cost you more than it saved.

Every value here that a published standard defines a check for carries the correct check. That is a small amount of arithmetic and it changes what the data is for: you can point your real validation at it.

Card numbers carry the Luhn check digit of ISO/IEC 7812-1, computed over the digits that precede it, and sit on the published test BIN of the brand you pick.
IBANs satisfy ISO 7064 mod-97 — the check digits are chosen so that the rearranged, letter-expanded number leaves a remainder of 1 — and are the exact length that country registers, which mod-97 alone would not catch.
ISBN-13 and EAN-13 values carry the alternating 1-3 weighted check digit, under one of the two GS1 prefixes the ISBN system was allocated.
UUIDs have the version nibble and the two variant bits RFC 9562 requires, so a parser reports v4 or v7 rather than shrugging.
Addresses, timestamps, semantic versions and currency codes are written in the form their standard defines, not an approximation of it.

None of that makes the data true. It makes it well-formed, which is the only property a fixture can honestly claim.

The seed, and why it is the whole point

A generator that gives you different rows every time is a toy. The moment the data goes into a test, a demo or a screenshot, you need to be able to get it back — after a refresh, on a colleague’s machine, in CI a year from now.

So the randomness here is seeded. The seed is a string you choose, and the same seed with the same schema and the same row count produces byte-identical output everywhere. The generator is xoshiro128**, seeded through splitmix64; both are published algorithms with reference implementations, and this page is tested against output transcribed from those references rather than against itself.

seed  "orders-2026"     same rows, every time, everywhere
seed  "orders-2027"     a completely different set

field stream = hash(seed, field name)
row N of a field depends on nothing but the seed, the name and N

That last line is worth reading twice, because it is what makes the tool usable rather than merely reproducible. Each field draws from its own stream, keyed on its name. Add a column and every existing column comes out identical. Raise the row count from 100 to 1000 and the first hundred rows are the ones you already had. A fixture you committed yesterday still matches after you extend the schema today.

The honest cost of keying on the name is that renaming a field replaces its data, since the name is half the seed. The null rate is the one setting deliberately exempt: the decision to blank a value is taken after the value is drawn, so turning nulls on removes some rows without disturbing the rest.

One warning that follows directly from all of this. A seeded generator is predictable by design — that is the feature. Nothing it produces may ever be used as a password, a token or a key. For those, use a generator that draws from the platform’s cryptographic source.

Ranges that are reserved so your data cannot be real

A generator that emits addresses at a real free-mail domain is handing you a loaded gun. Test suites send mail. Staging environments get pointed at production SMTP. Load tests hammer whatever IP address is in the fixture. When the value belongs to somebody, the accident reaches them.

Standards bodies anticipated this and set aside ranges that are guaranteed never to be assigned. Every default here draws from one of them:

Email lands on example.com, example.net and example.org, which RFC 2606 reserves permanently, alongside the .test, .example and .invalid top-level domains RFC 6761 adds.
Phone numbers use 555-0100 through 555-0199, the block North American numbering reserves for fiction — which is why films use it.
IPv4 addresses come from 192.0.2.0/24, 198.51.100.0/24 and 203.0.113.0/24, the three documentation networks of RFC 5737, and IPv6 from 2001:db8::/32 per RFC 3849.
MAC addresses set the locally-administered bit, which the IEEE guarantees it will never assign; the RFC 7042 documentation block is offered too, though it holds only 256 addresses.
Card numbers are built on the four published test BINs rather than a live issuing range, so a Luhn-valid number cannot coincide with a real card.

Each of these can be overridden when you have a reason — a domain of your own for a staging environment, a CIDR block that matches your network. The default is the safe answer, and the override is yours to make deliberately.

The names and places are drawn from the US Census Bureau’s published name distributions and its list of incorporated places. They are common English-language names, which means a generated name can coincide with a real person’s — as any name can. Treat the output as what it is: plausible strings, not people.

Fields that refer to each other

Independent columns produce rows that fall apart on inspection. A user called Dana Levy whose email address is unrelated to her name looks broken in a screenshot, and an updated timestamp that precedes the created one will fail a real assertion.

Rather than a special case for each pair, there is one mechanism: any setting marked as taking references may name another field in double braces, and it is filled in from the same row. The fields are then generated in dependency order rather than the order you listed them, and a circle of references is reported as a schema error instead of hanging.

It reaches further than emails. A template field builds any string you like out of other columns, with an optional case transform. A date field’s lower or upper bound may name another date field, which is how you get a timeline that holds together. And when a referenced value is null, the field that depends on it is null too, rather than quietly falling back to a default window the schema never mentioned.

Getting it out: JSON, NDJSON, CSV, SQL

JSON is the obvious one and comes indented or on a single line. NDJSON — one compact object per line — is what log pipelines and streaming importers expect, and it is the format to paste into a tool that reads a record at a time.

CSV follows RFC 4180: fields are quoted only when they contain a comma, a quote or a line break, an embedded quote is doubled, and lines end with CRLF. That is the form spreadsheets and database bulk loaders agree on.

SQL is where generators usually get careless, because the correct answer depends on the dialect. Identifier quoting differs — PostgreSQL and SQLite take double quotes, MySQL takes backticks, SQL Server takes brackets — and each doubles its own quote character inside a name. String literals double the single quote everywhere, but MySQL also reads a backslash as an escape unless NO_BACKSLASH_ESCAPES is set, so a Windows path ending in one would otherwise swallow the closing quote. Booleans are the third split: PostgreSQL has a real boolean type and the others want 1 and 0. And SQL Server refuses a table value constructor with more than a thousand rows, so a large export is emitted as several statements rather than one that fails.

PostgreSQL   INSERT INTO "records" ("id", "ok") VALUES (1, TRUE);
MySQL        INSERT INTO `records` (`id`, `ok`) VALUES (1, 1);
SQLite       INSERT INTO "records" ("id", "ok") VALUES (1, 1);
SQL Server   INSERT INTO [records] ([id], [ok]) VALUES (1, 1);

The schema is a file

The pane beside the builder is the same schema written as JSON, and it works in both directions: edit the fields and it updates, paste a schema in and the builder follows. Options left at their default are omitted, so what you read back is the decisions you made rather than every knob the tool owns.

That file, plus the seed it contains, is the whole reproducible unit. Commit it next to the test that consumes the data and the fixture becomes something a reviewer can read and a colleague can regenerate, instead of a large blob of values nobody can explain.

Frequently asked questions

Are the credit card numbers real?: They are valid and they are not real. Each one carries a correct Luhn check digit, so a payment library will accept its format, and each is built on one of the four published test BINs rather than a live issuing range, so it cannot coincide with a card somebody holds. They will not authorise a payment anywhere.
Will the same seed really give me the same data next year?: Yes. The generator is a published algorithm with a fixed reference implementation, not a browser API whose behaviour can change, and this page is tested against output transcribed from that reference. Nothing reads the clock: date ranges are literal values in the schema. Keep the schema JSON and the seed it contains and the rows come back exactly.
Why did adding a column change nothing else?: Because each field draws from its own stream, keyed on the seed and the field name. It is deliberate: a fixture that reshuffles every time you extend the schema is one you cannot keep in a repository. The same property means raising the row count leaves the earlier rows alone.
I renamed a field and its data changed.: That follows from the same design — the field name is half of its stream key. If you want to keep the values, rename the column downstream instead, or accept the new draw. There is no way to have both stable-under-rename and stable-under-reorder without a hidden identifier the schema file would then have to carry.
Can I use this to generate a password or an API key?: No. Everything here comes from a seeded pseudo-random generator, which is predictable by design and is the reason the output is reproducible. A secret has to come from the platform’s cryptographic source. Use a dedicated token generator for that.
How do I make the email match the name?: Add a template field and write the other columns in double braces — something like {{first_name}}.{{last_name}}@example.com — then set the case transform to lower. The fields are generated in dependency order, so the template can name a column that appears after it in the list.
How many rows can it produce?: Ten thousand, across up to forty fields. Generation is fast enough to stay on the main thread at that size; what actually gets uncomfortable is the resulting text, which is why the pane shows a truncated preview while copy and download take the whole thing.
Does any of this leave my browser?: No. The generator, the corpus of names and every output format run as JavaScript on the page. There is no server call, and nothing you type into the schema is sent anywhere.