The original title is: "Generate TypeScript Types from JSON (and where the auto-generators trip up)"

Short summary

A concise guide to generating TypeScript types from JSON, covering browser-based tools like jsonviewertool.com and the predictable gaps auto-generators leave: nullable fields, empty arrays, optional fields, union types, and numeric enums. For production code, the author recommends generating from JSON Schema or OpenAPI specs instead of raw samples, since schemas encode nullability and optionality that a single sample cannot. Sample-based generation is a draft, not a contract.

• •Auto-generators miss nullable fields, empty array element types, optional fields, and union types
• •Use json-schema-to-typescript or openapi-typescript for maintained code, not raw samples
• •Always review generated types manually — nullability and optional fields are where runtime bugs hide

Generated with AI, which can make mistakes.