SQL DDL to JSON Schema Converter

Transform SQL CREATE TABLE statements into standardized JSON Schema specifications.

At a glance

SQL DDL to JSON Schema Converter is a free developer utility that reverse-engineers PostgreSQL, MySQL, and SQLite CREATE TABLE DDL into standardized JSON Schema (Draft 2020-12 and Draft-07). It maps column data types, formats, NOT NULL constraints, enums, and defaults 100% client-side in browser memory.

Universal Switcher:
From:
To:
Developer Suite: SQL to JSON Schema JSON Schema to SQL SQL to GraphQL GraphQL to SQL SQL to Drizzle SQL to Kysely

100% Client-Side SQL DDL to JSON Schema Converter

Zero Server Uploads

Reverse-engineer PostgreSQL, MySQL, and SQLite CREATE TABLE statements into standardized JSON Schema (Draft 2020-12 / Draft-07) with nullability, formats, constraints, and defaults.

Local Browser Sandbox
Presets:
0 lines · 0 chars
0 tables · 0 properties
0 Tables 0 Properties
Client-Side Evaluated

Why Use This SQL DDL to JSON Schema Converter?

100% Client-Side Privacy: Your proprietary database schema definitions never leave your device.
Multi-Dialect Parser: Accurately parses PostgreSQL, MySQL, and SQLite table declarations.
Inverse Nullability: Automatically maps NOT NULL column modifiers into JSON Schema required arrays.
Rich Constraints Extraction: Captures VARCHAR maxLength, CHECK/ENUM lists, default values, and format annotations.

How to Use SQL DDL to JSON Schema Converter

1

Input SQL DDL

Paste your SQL CREATE TABLE statements into the editor or load a database preset.

2

Configure Options

Choose your preferred JSON Schema draft (2020-12 or Draft-07) and toggle explicit null unions.

3

Copy or Download

Copy the generated JSON Schema or download it directly as schema.json.

PostgreSQL CREATE TABLE to JSON Schema example

Converts a PostgreSQL users table into a JSON Schema User model with required fields, maxLength constraints, and format annotations.

SQL DDL Input Source 
CREATE TABLE "users" (
  "id" SERIAL PRIMARY KEY,
  "name" VARCHAR(100) NOT NULL,
  "email" VARCHAR(255) NOT NULL,
  "bio" TEXT
);
JSON Schema Output Processed 
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "User",
  "type": "object",
  "properties": {
    "id": { "type": "integer" },
    "name": { "type": "string", "maxLength": 100 },
    "email": { "type": "string", "maxLength": 255, "format": "email" },
    "bio": { "type": "string" }
  },
  "required": ["id", "name", "email"]
}

Technical Specifications & Engine Details

Technical specifications and engine details for SQL DDL to JSON Schema Converter
Specification Details
Supported SQL Dialects PostgreSQL, MySQL / MariaDB, SQLite, ANSI SQL
Supported JSON Schema Drafts Draft 2020-12 ($defs), Draft-07 (definitions)
Execution Mode 100% Client-Side In-Browser (Zero server latency)
Nullability Mapping NOT NULL columns → required array, optional → omitted or union with null
Extracted Constraints maxLength, format (uuid, date-time, date, time), enum, default, description
Maintained by Pragyan Pahadi

100% Client-Side Privacy Guarantee

Your files remain strictly on your local device. Zero data is transmitted to external servers.

Frequently Asked Questions

How are SQL column data types mapped to JSON Schema?
SQL integer types (INT, SERIAL, BIGINT) map to integer. Decimals and floating-point types map to number. VARCHAR, CHAR, and TEXT map to string with maxLength populated when specified. JSON and JSONB map to object.
How does SQL nullability map to JSON Schema?
Columns with NOT NULL are listed in the parent required array. Nullable columns are omitted from required. When explicit null unions are enabled, nullable columns are typed as [type, "null"].
How are multiple tables represented in JSON Schema?
When multiple CREATE TABLE statements are provided, a master database schema is generated where each table is encapsulated in $defs (Draft 2020-12) or definitions (Draft-07).
Is any SQL schema data sent to external servers?
No. The entire conversion runs locally inside your browser sandbox. No schema, column names, or structural data are ever transmitted over the network.

Methodology

This tool runs entirely in your browser. The example above shows a representative input and the result it produces.

Last updated .

Recommended Next Steps in Developer Utilities

View All Developer Utilities →

JSON Schema to SQL DDL Converter

Convert JSON Schema Draft 2020-12 and OpenAPI models into multi-dialect SQL DDL (PostgreSQL, MySQL, SQLite) with primary keys, formats, and constraints.

JSON Schema to SQL DDL Converter →

SQL DDL to GraphQL Schema Generator

Convert SQL CREATE TABLE statements into GraphQL SDL types, inputs, queries, and mutations online.

SQL DDL to GraphQL Schema Generator →

GraphQL Schema to SQL DDL Converter

Convert GraphQL SDL types into SQL CREATE TABLE DDL queries for PostgreSQL, MySQL, and SQLite.

GraphQL Schema to SQL DDL Converter →

SQL to Drizzle ORM Schema Converter

Convert SQL CREATE TABLE DDL into clean Drizzle ORM TypeScript schema definitions online.

SQL DDL to Drizzle ORM Schema Generator →

JSON Schema to TypeScript Converter

Generate clean TypeScript interfaces and types from JSON Schema Draft-04, Draft-07, and Draft 2020-12 specifications online.

JSON Schema to TypeScript Converter →

JSON Schema to Prisma Schema Converter

Convert JSON Schema Draft 2020-12 and OpenAPI models into production-ready Prisma schema models, enums, relations, and timestamps.

JSON Schema to Prisma Schema Converter →