AI Developer Tools for Structured Output & Data
Getting reliable, machine-readable data out of a language model is most of the work in an LLM feature. These tools help you design schemas for structured outputs and function calling, repair and validate what the model returns, prepare fine-tuning datasets, and compare embeddings — all locally in your browser.
{S} JSON Schema Generator Generate a JSON Schema from sample JSON. Strict mode makes it valid for OpenAI structured outputs, and one click wraps it as an OpenAI response_format, OpenAI function or Anthropic tool definition. Zod JSON to Zod Convert sample JSON into a Zod schema plus its inferred TypeScript type. Ready for validating API responses and LLM structured outputs with the Vercel AI SDK or OpenAI SDK. JL JSONL Validator Validate JSON Lines files line by line, preview records in a table, and check OpenAI-style chat fine-tuning data (roles, missing assistant replies, empty content). Convert JSONL ⇄ JSON arrays. FIX JSON Repair Fix invalid JSON instantly: strips markdown fences and chatty text, adds missing quotes and commas, removes trailing commas and comments, converts Python True/None, and closes JSON that was cut off mid-stream. ⇄ Chat Format Converter Convert conversation histories between the OpenAI Chat Completions, Anthropic Messages and Gemini request formats — including system prompts, images, tool calls and tool results. API OpenAPI to LLM Tools Convert an OpenAPI 3 or Swagger 2 spec (JSON or YAML) into tool definitions for OpenAI function calling, Anthropic Claude tool use or MCP servers. $refs are resolved and each endpoint becomes one tool. ✓{} JSON Schema Validator Validate JSON data against a JSON Schema (draft-07, 2019-09, 2020-12) and see every error with its path. Paste an OpenAI response_format or a Claude tool definition directly — the schema is extracted automatically. cos Vector Similarity Calculator Paste two embedding vectors and get cosine similarity, cosine distance, angle, dot product, Euclidean and Manhattan distance. Accepts raw arrays or full embedding API responses.