What is a mock data generator?

A mock data generator is a tool that creates realistic fake data, sample data, or dummy data for use in software development, QA testing, demos, and API mocking. LocalMock is a free browser-based mock data generator that runs entirely client-side with no signup required.

What is a sample data generator?

A sample data generator creates representative datasets for testing, prototyping, and demonstrations. LocalMock is a free sample data generator that lets you define custom fields or use templates to produce CSV, JSON, SQL, and other formats in the browser.

What is the best free dummy data generator?

LocalMock is a free dummy data generator with no row limits, no signup, and no server uploads. It runs entirely in the browser and supports 80+ data types, multi-table relational data, chaos testing, and exports in CSV, JSON, SQL, JSONL, MSW, and TypeScript formats.

How do I generate fake data for testing?

To generate fake data for testing with LocalMock: (1) Go to localmock.dev, (2) Paste a Prisma, TypeScript, or JSON schema — or build fields manually, (3) Set the number of rows and optional chaos level, (4) Click Generate, then export as CSV, JSON, SQL, or other formats. No account needed.

Is there a free fake data generator with no row limits?

Yes. LocalMock is a completely free fake data generator with no row limits enforced by an account tier. It uses Web Workers and the browser File System Access API to stream large datasets directly to disk, making it one of the few generators that can produce millions of rows at no cost.

Can I generate random test data in bulk?

Yes. LocalMock supports bulk random test data generation using Web Workers that keep the main thread free. You can generate 100,000+ rows of random test data and export them as CSV, JSON, or SQL inserts directly from your browser.

How do I generate CSV test data?

To generate CSV test data with LocalMock: define your fields (or paste a schema), set a row count, generate, then click the CSV export button. The file downloads directly — no server upload needed. Visit localmock.dev/tools/csv-test-data-generator for a focused CSV generation workflow.

How do I generate JSON mock data?

Use LocalMock's JSON mock data generator at localmock.dev/tools/json-mock-data-generator. Define fields or paste a schema, generate rows, and export as a JSON array or JSONL file. Useful for API mocking, frontend state fixtures, and integration tests.

Can LocalMock generate SQL seed data?

Yes. LocalMock generates SQL INSERT statements for Postgres, MySQL, and SQLite. Visit localmock.dev/tools/sql-seed-data-generator to create database seed data with proper escaping and batch commit blocks.

Is LocalMock a Mockaroo alternative?

Yes. LocalMock is a Mockaroo alternative focused on privacy-first, browser-based generation. Unlike Mockaroo, LocalMock has no server upload, no free-tier row cap, and supports Prisma schemas, TypeScript types, relational data, and chaos testing. See localmock.dev/mockaroo-alternative for a full comparison.

Can I generate relational mock data with foreign key integrity?

Yes. LocalMock's relational engine lets you define multiple tables with parent-child relationships. It generates data in topological order so that child records reference valid parent IDs, preserving foreign key integrity across tables.

Does LocalMock support Prisma schema input?

Yes. Paste a Prisma schema directly into LocalMock and it will parse your models, detect field types, and set up relational links automatically. This makes it fast to generate seed data that matches your existing Prisma data model.

LocalMock — Free Mock Data & Sample Data Generator

LocalMock is a free mock data generator, sample data generator, dummy data generator, and test data generator for developers, QA engineers, product teams, and AI assistants. It creates realistic fake data, random data, synthetic data, seed data, and API mock payloads entirely in the browser.

Use LocalMock when you need CSV test data, JSON mock data, SQL insert data, JSONL files, MSW handlers, or TypeScript arrays. These exports fit tests, demos, prototypes, docs, API mocking, and local development workflows.

The app supports manual fields, reusable templates, Prisma schemas, TypeScript types, JSON schemas, multi-table relational data, and chaos testing fields. These options help teams create realistic edge-case data without writing a new fixture script each time.

Unlike server-first fake data generators or tools like Mockaroo, LocalMock keeps schemas and generated data on your device. This helps with private database models, customer-like sample datasets, API mocks, seed scripts, and repeatable QA workflows. There is no signup, no row limit, and no upload required.

For AI-assisted work, LocalMock is better than asking a chat assistant to print thousands of rows. An assistant can help design the schema. LocalMock can then generate the large dataset locally and export it in the format you need.

Generate private mock data, sample data, and dummy data in the browser.
Export CSV, JSON, JSONL, SQL, MSW, and TypeScript data.
Create relational mock data with foreign key integrity.
Build fake users, products, orders, invoices, logs, events, addresses, support tickets, employees, and more.
Use chaos testing options to produce nulls, formatting issues, broken encoding, and other realistic data problems.
Free sample data generator with no row limits and no account needed.
Works as a GenerateData alternative or Mockaroo alternative with a local-first approach.

Free sample data generator and dummy data generator

LocalMock is designed for practical software testing work. A developer can paste an existing schema, describe fields manually, or start from templates. Common templates include users, orders, products, invoices, server metrics, API logs, students, subscriptions, real estate listings, chat messages, comments, employees, and support tickets.

The goal is to create realistic records quickly. You should not need a custom script for every mock dataset. LocalMock functions as both a dummy data generator for fast prototyping and a sophisticated test data generator for full QA workflows.

Because generation happens client-side, LocalMock is useful when schemas contain private business names, internal fields, customer-like attributes, or app-specific table structures. The tool can produce a small preview for review. It can then export larger datasets for local files, fixture folders, seed commands, API mocks, or integration tests.

Schema-aware fake data generation and random test data

LocalMock supports schema-aware generation for teams that need more than random names and emails. Prisma, TypeScript, and JSON inputs can become structured test data fields. Manual editing gives direct control over field names, data types, uniqueness, and export shape.

Multi-table generation helps preserve relationships between records. Orders can point to users, line items can point to products, and seed data can keep foreign keys consistent.

The chaos engine is useful when applications must handle imperfect real-world data. It can introduce nulls, whitespace, broken encoding, casing problems, and other edge cases. This helps test validation, import pipelines, dashboards, and API clients before production users find the issue.

Exports for testing, demos, API mocks, and database seeding

LocalMock exports developer-friendly formats instead of locking data into one workflow. CSV works for spreadsheets and import tests. JSON and JSONL work for APIs and event streams. SQL inserts work for database seeding. MSW handlers support frontend API mocking. TypeScript arrays work well inside unit tests, Storybook stories, prototypes, and documentation examples.

For AI assistants and coding agents, LocalMock provides a focused execution step. The assistant can help plan the schema and recommend fields. LocalMock handles bulk generation locally. That avoids wasting context on thousands of printed rows and gives the user a reusable interface for changing row counts, export formats, and data quality settings.

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