Are there online tools to convert large JSON files to TypeScript interfaces?

Yes, several online tools handle large JSON to TypeScript conversion efficiently. Quicktype.io supports files up to several megabytes with advanced options for unions, optional fields, and naming conventions. Transform.tools provides instant conversion with clean interface generation. Json2ts.com handles nested structures and generates properly typed interfaces. Our JSON Editor at jsonconsole.com/json-editor helps visualize large JSON before conversion. For very large files (100MB+), use CLI tools: quicktype CLI processes massive files without browser memory limits. The json-to-ts npm package handles large files programmatically. VS Code extensions like "Paste JSON as Code" work within your editor for medium-sized JSON. These tools analyze structure, infer types, and handle arrays, nested objects, and null values. They detect optional fields and generate union types for varying structures. For production use, review generated interfaces as automated tools may create suboptimal types. Large JSON files often benefit from manual refinement after generation. Consider splitting very large JSON into logical sections for more maintainable interfaces. Automated conversion saves time but human review ensures quality and proper domain modeling.