Schemint

paste PostgreSQL or JSON, get your schema reviewed like a senior would

Mock data generator - realistic JSON from a sample payload

Paste a payload, get realistic mock rows. Nothing you paste is stored.

Paste a JSON payload (or a CREATE TABLE) and get mock rows that match its shape with data that looks real: names, emails, prices with two decimals, ISO timestamps. Fields that are nullable in your sample get some nulls, and the same input always produces the same rows, so fixtures don't churn in code review.

A seed SQL script comes along for database tests. Generated on the server, discarded after the response.

Try it on your own JSON

Example

JSON in:

[
  {"id": 1, "sku": "A-100", "name": "Widget", "price": 9.99, "in_stock": true, "created_at": "2024-01-15T10:30:00Z"},
  {"id": 2, "sku": "B-220", "name": "Gadget", "price": 19.5, "in_stock": false, "created_at": "2024-02-01T08:00:00Z"}
]

Generated:

seed.sql

INSERT INTO payload (id, sku, name, price, in_stock, created_at) VALUES
    (1, 'RI-4214', 'Cameron Ellison', 322.5183, TRUE, '2024-07-17 04:45:28'),
    (2, 'ZQ-7197', 'Elizabeth Sanchez', 637.8153, TRUE, '2024-12-30 03:26:55'),
    (3, 'DC-3598', 'Brittney Harris', 65.0785, FALSE, '2025-02-14 02:18:18'),
    (4, 'RJ-6800', 'Thomas Johnson', 632.0513, FALSE, '2025-11-09 05:49:03'),
    (5, 'JA-1811', 'Christine Burton', 898.2809, FALSE, '2025-06-21 21:23:52');

payload.json

[
  {
    "id": 1,
    "sku": "RI-4214",
    "name": "Cameron Ellison",
    "price": 322.5183,
    "inStock": true,
    "createdAt": "2024-07-17 04:45:28"
  },
  {
    "id": 2,
    "sku": "ZQ-7197",
    "name": "Elizabeth Sanchez",
    "price": 637.8153,
    "inStock": true,
    "createdAt": "2024-12-30 03:26:55"
  },
  {
    "id": 3,
    "sku": "DC-3598",
    "name": "Brittney Harris",
    "price": 65.0785,
    "inStock": false,
    "createdAt": "2025-02-14 02:18:18"
  },
  {
    "id": 4,
    "sku": "RJ-6800",
    "name": "Thomas Johnson",
    "price": 632.0513,
    "inStock": false,
    "createdAt": "2025-11-09 05:49:03"
  },
  {
    "id": 5,
    "sku": "JA-1811",
    "name": "Christine Burton",
    "price": 898.2809,
    "inStock": false,
    "createdAt": "2025-06-21 21:23:52"
  }
]

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