Local browser generation. Nothing is uploaded.

Generate Custom Size Sample Test Files in Your Browser

Create dummy files up to 1GB for upload forms, parsers, API tests, demos, and QA workflows. Pick a preset or custom file size. Supported formats: TXT, CSV, JSON, XML, HTML, LOG, BIN, SVG, Markdown, YAML, TOML.

Instant download

Generate one file and download it immediately.

No server storage

Files are created in your browser and never touch our backend.

Simple formats only

Browser-safe text, data, SVG, and binary test files.

Format

Plain text sample with repeated safe content.

Size

Filename preview

sample-100kb.txt

Target size: 100 KB

Local browser generation

Generated locally in your browser. Nothing is uploaded, stored, or sent to TrueFileSize.

Preview

Sample TXT file generated locally by TrueFileSize.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeholder text for upload, parser, and QA testing.
This is safe placeh

What can you generate locally?

Format	Best for	Why it is safe in FE
TXT, LOG, Markdown	Text upload and parser tests	Plain text Blob
CSV, JSON, XML	Data import and API fixtures	Controlled templates
HTML, SVG	Markup parser and preview tests	No user script execution
BIN	Raw byte and upload size tests	Uint8Array bytes only
YAML, TOML	Config parser tests	Plain text templates

Guides for using generated files

Generate Sample Files in Your Browser

How local file generation works with Blob, TextEncoder, Uint8Array, and object URLs.

Read guide

Safe Dummy File Generator with No Upload

Why local generation is useful when you need a private dummy file with a custom file size.

Read guide

Test Upload Forms with Generated Files

A practical workflow for testing upload forms, file type validation, and size boundaries.

Read guide

Frequently Asked Questions

Are generated files uploaded to TrueFileSize?

No. Files are generated locally in your browser with native Web APIs. Nothing is uploaded, stored, or sent to TrueFileSize.

Is my generated file private?

Yes. The generated file stays on your device until you download it. TrueFileSize does not receive the content, filename, or generated bytes.

Which formats can be generated locally?

This tool supports lightweight formats that browsers can create safely: TXT, CSV, JSON, XML, HTML, LOG, BIN, SVG, Markdown, YAML, and TOML.

Can I choose a custom file size?

Yes. You can pick presets or enter a custom file size up to 1GB, which is useful for testing upload limits, parser behavior, and UI validation states.

How do developers and QA teams use this tool?

Developers and QA teams use generated files to test upload forms, API validation, CSV and JSON parsers, empty-state handling, boundary sizes, and demo workflows without committing fixture files.

How can regular users use it?

Regular users can create harmless dummy files for checking email attachments, form limits, storage workflows, or whether an app accepts a certain file type.

Why not PDF, MP4, DOCX, XLSX, or ZIP?

Those formats need heavier encoders or libraries, increase client bundle size, and are easier to generate incorrectly. TrueFileSize keeps those as prebuilt sample files served from the CDN.

Does this increase the website bundle size?

The generator uses native browser APIs such as Blob, Uint8Array, TextEncoder, and URL.createObjectURL. It does not import heavy PDF, Office, ZIP, image, audio, or video libraries.

Which browsers are supported?

Modern Chrome, Edge, Firefox, and Safari browsers are supported. The required APIs are standard browser features for creating and downloading Blob objects.

What is the maximum file size?

The maximum generated file size is 1GB per action. Large files are created in browser memory before download, so they may be slow or memory-heavy on low-memory devices.

When should I use CDN-hosted download tests instead?

Use CDN-hosted Download Tests when you need very large files above 1GB, bandwidth testing, resumable upload checks, or format-specific samples such as PDF, MP4, DOCX, XLSX, or ZIP.

Need large CDN-hosted files instead?

Browser generation can create files up to 1GB, but large files use browser memory before download. For CDN-hosted files, bandwidth tests, or 10GB samples, use the prebuilt files served from the TrueFileSize CDN.

Open Download Tests