Mock API generator. Generate realistic mock API responses from JSON Schema definitions with customizable string lengths, number ranges, and
100% browser-based — your data never leaves your device
Generate mock API responses from JSON schemas for rapid development.
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Mock API Generator is a free online api tool that generate mock api responses from json schemas for rapid development. It works entirely in your browser — no downloads, no installations, and no server uploads required. backend developers, QA engineers, integration specialists use Mock API Generator when they need a fast, privacy-respecting way to process api data without installing additional software. It supports capabilities such as schema-based, customizable, bulk generation. Additional features include export formats. Common use cases include generate realistic mock api responses from openapi schemas for frontend development, create test data for unit tests and integration tests from json schema definitions, simulate api responses during backend development to unblock frontend teams. All processing happens locally using modern browser APIs, which means your data never leaves your device. This makes Mock API Generator ideal for working with sensitive data, proprietary code, or any situation where privacy matters.
Mock API Generator is a free online api tool that helps you generate mock api responses from json schemas for rapid development. Key capabilities include schema-based, customizable, bulk generation. All processing is done locally in your browser — no data is uploaded, stored, or shared with any server. There are no sign-ups, no file size limits, and no hidden charges. It is commonly used to generate realistic mock api responses from openapi schemas for frontend development.
Paste your JSON Schema definition that describes the structure of the data you want to generate.
Customize string lengths, number ranges, array sizes, and enum selections to match your production data.
Click Generate to create realistic mock data based on your schema and configuration.
Copy individual fields or export the complete mock data as JSON for use in your application.
| Category | Details |
|---|---|
| Input Limits | Request timeout: Configurable (default: 30 s) |
| Response size: Browser memory bound | |
| Supported Formats | HTTP/1.1, HTTP/2, WebSocket, JSON, XML, Form data, Binary |
| Browser Engine |
|
All operations run entirely in your browser using built-in API APIs. No server uploads, no data storage, and no third-party requests.
Mock API Generator is ideal when you need to generate realistic mock api responses from openapi schemas for frontend development without installing software or uploading data to a server. Since everything runs in your browser, there is no setup time and no risk of your data being stored on external servers. For for collaborative API development and testing, consider using Postman. For for lightweight REST and GraphQL debugging, Insomnia may be a better fit. Mock API Generator fills the gap between heavyweight desktop tools and insecure online services that require uploading your data.
No. Mock API Generator processes everything entirely in your browser using JavaScript. Nothing you type, paste, or upload is ever transmitted to any server. Your data never leaves your device.
It parses your JSON Schema definition and generates realistic-looking data that matches the schema's types, formats, and constraints.
Yes. Configure string lengths, number ranges, array sizes, and enum selections to customize the generated mock data for your testing needs.
Generate realistic mock data from JSON Schema definitions.
Control string lengths, number ranges, array sizes, and enum selections.
Generate multiple mock items at once for list endpoints.
Copy as JSON or generate ready-to-use response examples.
Mock API Generator is useful in a variety of scenarios across different workflows:
Generate realistic mock API responses from OpenAPI schemas for frontend development
Create test data for unit tests and integration tests from JSON Schema definitions
Simulate API responses during backend development to unblock frontend teams
Adjust minimum and maximum string lengths in the schema to match your production data constraints for more realistic mock output.
Generate 20-50 mock items at once to test pagination, filtering, and sorting in your frontend components.
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