JSON Schema checks

jsonb-schemas makes the database reject a jsonb value that doesn't match its JSON Schema. Give a gen.json entry a schema, and the module adds a pg_jsonschema check constraint on that column, so a row the generated types would reject never lands, whichever client wrote it.

better-supabase add jsonb-schemas

export default defineConfig({
  gen: {
    json: {
      "customers.metadata": {
        import: "./lib/metadata.ts#CustomerMetadata",
        schema: CustomerMetadata,
      },
    },
  },
  blocks: ["jsonb-schemas"],
});

schema takes a JSON Schema object, or any Standard JSON Schema value (zod 4, valibot, arktype).

What it installsCopy Anchor Link

The module enables pg_jsonschema and adds better_supabase.check_json_schema(), a trigger that runs before the check constraint of the same name. It raises 23514 with the hint JSON_SCHEMA_INVALID and the schema errors as a JSON array in the detail, which the client maps to a validation error on the column. A SQL null passes, as it does for the check.

The SQL modules page covers existing rows that don't match.