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Generate realistic JSON mock data payloads and synthetic fixtures from JSON Schema, Zod, and TypeScript definitions with 100% browser privacy.
Convert JSON Schemas, Zod definitions, or TypeScript interfaces into realistic synthetic JSON payloads and test fixtures instantly.
Loading...The HiMat JSON Schema & Zod Mock Data Generator is a free browser-local utility engineered to convert structural schema declarations into realistic, context-aware synthetic JSON mock payloads. Whether you pass W3C JSON Schema specifications (Draft 4/7/2020-12), Zod schema objects, or TypeScript interface code, our smart mock engine inspects property names and formats to automatically synthesize accurate data types—including full names, emails, UUIDs, ISO timestamps, prices, and address fields.
Your API specs, Zod definitions, and generated mock payloads remain strictly inside your browser memory. No text or data is ever uploaded to remote servers.
Smart property key matching generates realistic data (emails, UUIDs, dates, full names, prices) rather than generic placeholding strings like "string_1".
Instantly generate single JSON objects or custom arrays containing 1 to 50 mock records for unit testing, seed scripts, and frontend component mocks.
Zero network requests. Proprietary JSON schemas, Zod definitions, and data models are evaluated 100% in local browser memory.
Input W3C JSON Schema specifications, Zod schema declarations (`z.object({...})`), or TypeScript interfaces to generate synthetic mock data.
Intelligently generates realistic names, emails, UUIDs, ISO timestamps, phone numbers, street addresses, prices, and avatar URLs based on property key names.
Configure mock array size (1 to 50 items) and nested object depth for scalable synthetic data fixtures.
Inspect formatted JSON, search/filter keys, copy formatted output to clipboard, or download ready-to-use `.json` mock files.
Load pre-configured production schemas (User Profile, E-Commerce Order, SaaS Subscription, AI Agent Tool Output) with one click.
Answers to common developer questions about schema mock data generation and client-side privacy.
Our browser-local generator analyzes your JSON Schema (Draft 4, 7, 2020-12) or Zod/TypeScript definitions, inspects property keys and types, applies context-aware mock generators (names, emails, dates, numbers, booleans, arrays), and compiles realistic JSON mock data in real time.
No. The HiMat JSON Schema & Zod Mock Data Generator operates 100% locally in your web browser. Neither your schema, property names, nor generated mock data payloads ever leave your device.
Our smart mock engine inspects property names and formats to automatically generate realistic values for emails, full names, usernames, UUIDs, ISO dates, timestamps, URLs, phone numbers, prices, IP addresses, booleans, and custom enums.
Mock data allows frontend engineers to build UI components before backend APIs are ready, enables unit/integration testing with predictable fixtures, and provides synthetic response payloads for AI agent tool function calling tests.
Yes, 100% free with no account registration required, no daily rate limits, and zero advertisements.
Convert TypeScript interface definitions and Zod schemas into W3C JSON Schema (Draft 7 / 2020-12) with 100% browser-local privacy.
Paste a JSON Schema spec (Draft 4/7/2020-12 with $ref, enums, required) and get TypeScript interfaces and Zod schemas. 100% browser-local.
Paste sample JSON or an API response and auto-infer TypeScript interfaces and Zod schemas. No schema needed. 100% browser-local.
Convert GraphQL SDL schemas (types, inputs, enums, unions) into static TypeScript interfaces and runtime Zod validation schemas with 100% browser-local privacy.
Convert OpenAPI v2/v3/v3.1 JSON or YAML specs into clean TypeScript interfaces, Zod schemas, and fetch API client helpers locally in browser memory.
Build, validate, test, and convert JSON schema function calling & tool definitions for OpenAI, Claude, LangChain, and DeepSeek with 100% browser privacy.
HiMat Technology designs, builds, and deploys high-performance web applications, tRPC/REST backend APIs, and multi-agent AI solutions for high-growth tech companies.