Is the JSON generation done on the server?

No. All JSON generation happens entirely in your browser to ensure privacy and performance.

How accurate is the file size?

We target the exact byte size by adjusting a dedicated padding field, producing deterministic sizes for compact or pretty-printed JSON.

Can I choose different JSON structures?

Yes. Choose from array of objects, object map, or nested structures depending on your test scenario.

What is the maximum size I can generate?

Practically, you can generate very large files. Browser memory and device capability are the main limits. Try generating in steps if you hit limits.

Why would I need exact-size JSON files?

Exact-size JSON files are essential for testing API upload limits, validating file size restrictions, benchmarking network performance, and creating consistent test data for automated testing scenarios.

Are the generated files stored anywhere?

No. Files are generated locally in your browser and downloaded directly. Nothing is uploaded or stored on our servers, ensuring complete privacy.

What JSON structures are available?

You can choose from Array of Objects (e.g., user lists), Object Map (key-value pairs), or Nested Structure (deeply nested objects) depending on your testing requirements.

Can I use this for automated testing?

Yes! Generate consistent JSON files with exact sizes for use in automated test suites, CI/CD pipelines, and performance testing frameworks.

Download JSON Files by Exact Size

Need sample JSON files with specific sizes? Generate precise payloads in your browser with one click. Perfect for testing API uploads, rate limits, and performance. All processing happens client-side for complete privacy.

Download JSON Files by Size (Bytes, KB, MB)

Generate and download JSON files in precise sizes for testing APIs, upload limits, and performance scenarios. Client-side only for privacy—your data never leaves the browser.

No signup

Browser-only

Exact byte target

Quick Downloads

Select a preset size to instantly generate and download a JSON file. Files up to 200 MB are supported.

For custom sizes up to 200 MB, use the form below. Large files may take longer to generate.

Custom Size & Options

Choose structure and formatting, then generate an exact-size JSON file.

Structure

Pretty Print

Compact

Custom Size

Exact-size generation with a controllable padding field for precision. Maximum size: 200 MB.

Status: Ready

Benefits of Using Our JSON Size Generator

API Testing

Test your API endpoints with precisely sized payloads to validate upload limits and performance thresholds.

Performance Benchmarking

Measure how your applications handle different JSON file sizes for optimization and load testing.

Privacy Focused

All generation happens in your browser - no data is sent to servers, ensuring complete privacy and security.

How Our JSON Size Generator Works

Select Size

Choose from preset sizes or enter a custom size in bytes, KB, or MB.

Choose Structure

Pick the JSON structure type that matches your testing requirements.

Configure Format

Toggle between compact (minified) and pretty-printed formatting.

Generate & Download

Generate your exact-size JSON file and download it instantly.

Popular Use Cases

Test API upload limits with precisely sized payloads.
Benchmark network performance across different file sizes.
Validate client-side file validators and size restrictions.
Generate fixtures for E2E, integration, and unit tests.
Test file upload forms and progress indicators.
Simulate real-world data payloads for stress testing.

Ready to Get Started?

Choose from our suite of JSON tools to start processing your data right away.

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JSON Visualizer

Visualize JSON data as interactive graphs and tree structures.

JSON Escape/Unescape

Escape and unescape JSON strings for safe encoding in APIs and databases.