# Dummy File Generator

> Dummy File Generator (dummyfilegenerator.com) is a free web tool that creates dummy test files at exact byte sizes entirely in the browser — nothing is uploaded and no account is needed. It supports 28 formats (TXT, MD, VTT, HTML, PDF, DOCX, SVG, JPG, PNG, GIF, WEBP, MP3, WAV, MP4, WEBM, JS, TS, CSS, SCSS, JSON, CSV, XML, SQL, ZIP, YAML, INI, ENV, TOML) up to 512 MiB per file, and publishes QA guides, upload-testing scenarios, file-format references and developer tools for software testers and developers. The same generator is available as a free Chrome extension (https://chromewebstore.google.com/detail/ifbjgnnekhgbpejkknhlkhajfifpooak).

Last updated: 2026-09-28

## Key facts

- Generator URL: https://dummyfilegenerator.com/generator
- Price: free. No sign-up. Files are generated client-side with JavaScript and never sent to a server.
- Maximum size: 512 MiB (536,870,912 bytes) per file. Sizes are exact to the byte (WAV snaps to whole samples).
- Valid output: PDF, DOCX, ZIP, JPG, PNG, GIF, WebP and WAV files open in standard viewers even when padded. MP3, MP4 and WebM are minimal shells for MIME/size tests.
- Text formats (JSON, CSV, XML, YAML, code, etc.) accept custom body text and are padded with spaces so they stay parseable.
- Units: 1 KB = 1,024 bytes and 1 MB = 1,048,576 bytes in the generator. Use the size calculator for decimal (1,000) conversions.
- Downloaded files are named dummy.<extension>.
- Chrome extension: free on the Chrome Web Store at https://chromewebstore.google.com/detail/ifbjgnnekhgbpejkknhlkhajfifpooak (Chrome 116+, also Edge, Brave and Opera). It makes the same files from the toolbar and can put a file straight into the current page's upload box. Details: https://dummyfilegenerator.com/chrome-extension

## Tools

- [File generator](https://dummyfilegenerator.com/generator): Create a test file in any supported format at an exact byte size.
- [Chrome extension](https://dummyfilegenerator.com/chrome-extension): The generator in your Chrome toolbar; fills upload boxes directly. Install: https://chromewebstore.google.com/detail/ifbjgnnekhgbpejkknhlkhajfifpooak
- [File size calculator](https://dummyfilegenerator.com/tools/file-size-calculator): Convert bytes, KB, MB and GB in binary (1024) and decimal (1000) bases.
- [MIME type lookup](https://dummyfilegenerator.com/tools/mime-lookup): Find the MIME type for an extension, or extensions for a MIME type.
- [Magic byte sniffer](https://dummyfilegenerator.com/tools/magic-byte-sniffer): Identify a file type from its leading bytes, offline in the browser.
- [Standard sample files](https://dummyfilegenerator.com/standard-files): Ready-made small JSON, CSV, XML, YAML, SQL, SVG and other text samples.

## Generator presets (deep links)

- [5 MB PDF (boundary / upload-limit tests)](https://dummyfilegenerator.com/generator?preset=pdf-upload-5mb)
- [≈24 MB PDF (timeout / CDN stress)](https://dummyfilegenerator.com/generator?preset=pdf-stress-24mb)
- [≈8 MB JPEG (heavy raster uploads)](https://dummyfilegenerator.com/generator?preset=jpeg-large-approx-8mb)
- [Exactly 1,048,577 bytes JPEG](https://dummyfilegenerator.com/generator?preset=boundary-one-byte-over-1mb-jpg)
- [≈520 KB CSV (tabular import benchmarks)](https://dummyfilegenerator.com/generator?preset=csv-padded-520kb)
- [≈512 KB JSON (API payload probes)](https://dummyfilegenerator.com/generator?preset=json-padded-512kb)
- Any format and size: https://dummyfilegenerator.com/generator?ext=<extension>&bytes=<exact byte count> (e.g. ?ext=csv&bytes=520000)

## Ready-made test files

One page per common size, generated in the browser at exact bytes, with 1-byte-over/under variants: https://dummyfilegenerator.com/download/<size>-<format>
Sizes: 100kb, 500kb, 1mb, 2mb, 5mb, 10mb, 20mb, 25mb, 50mb, 100mb. Formats: pdf, jpg, png, mp4, mp3, docx, zip, csv, txt, json.

- [All test files](https://dummyfilegenerator.com/download)
- [PDF test files](https://dummyfilegenerator.com/download/pdf)
- [JPG test files](https://dummyfilegenerator.com/download/jpg)
- [PNG test files](https://dummyfilegenerator.com/download/png)
- [MP4 test files](https://dummyfilegenerator.com/download/mp4)
- [MP3 test files](https://dummyfilegenerator.com/download/mp3)
- [DOCX test files](https://dummyfilegenerator.com/download/docx)
- [ZIP test files](https://dummyfilegenerator.com/download/zip)
- [CSV test files](https://dummyfilegenerator.com/download/csv)
- [TXT test files](https://dummyfilegenerator.com/download/txt)
- [JSON test files](https://dummyfilegenerator.com/download/json)
- Example: [5 MB PDF test file](https://dummyfilegenerator.com/download/5mb-pdf)

## Chrome extension

- [Dummy File Generator for Chrome](https://dummyfilegenerator.com/chrome-extension): free extension that makes the same exact-size files from the toolbar, right-click menu or Alt+Shift+D, and can attach a file straight to the current page's upload box. No analytics, no remote code, works offline.
- [Install from the Chrome Web Store](https://chromewebstore.google.com/detail/ifbjgnnekhgbpejkknhlkhajfifpooak)

## Upload limits reference

- [File upload size limits of 43 services and frameworks](https://dummyfilegenerator.com/upload-limits): Gmail, Outlook, WhatsApp, Discord, Slack, GitHub, Nginx, PHP, Express, Django, Spring Boot and more, each with its official source (verified 2026-09-27).

## QA scenarios

- [5 MB dummy PDF for upload-limit testing](https://dummyfilegenerator.com/scenarios/five-mb-pdf-upload-boundary-test): Generate a deterministic ~5 MiB Portable Document Format file to exercise storage tiers, multipart boundaries, antivirus queues, and “file too large” messaging — without scraping random PDFs from the web.
- [Exact-byte dummy files for API & storage QA](https://dummyfilegenerator.com/scenarios/exact-byte-size-generator-for-backend-qa): Produce JSON, CSV, images, WAV, synthetic MP4/WebM shells, and more padded or trimmed to a precise byte footprint for boundary regressions.
- [Large padded CSV for import & ETL benchmarking](https://dummyfilegenerator.com/scenarios/large-padded-csv-for-import-benchmarking): Stress CSV parsers and upload routes with deterministic payloads — avoid inventing PHI in spreadsheets copied from staging.
- [Defensive MIME tests: mismatched signatures vs extensions](https://dummyfilegenerator.com/scenarios/defensive-testing-extension-versus-sniffed-mime): Document benign QA workflows pairing extension checks with sniffers — never deceptive files aimed at humans.
- [~24 MB synthetic PDF upload stress](https://dummyfilegenerator.com/scenarios/long-running-upload-stress-twenty-four-mb-pdf): Provoke sluggish paths—chunked uploads, Axios defaults, multipart backpressure, antivirus sandboxes—without juggling multi-gigabyte objects during early regressions.
- [~512 KB padded JSON for REST clients](https://dummyfilegenerator.com/scenarios/json-payload-bloat-rest-client-tests): Exercise JSON.parse heavy paths without importing scrubbed-but-still-sensitive production dumps.
- [Team shareable generator links (preset query params)](https://dummyfilegenerator.com/scenarios/team-shareable-presets-hash-links-playbook): Encode MIME + sizing (or canned presets) in URLs — paste into runbooks instead of juggling shared drives.

## Guides

- [How to generate dummy files for QA testing](https://dummyfilegenerator.com/guide/how-to-generate-dummy-files)
- [File upload testing guide & checklist](https://dummyfilegenerator.com/guide/file-upload-testing-guide)
- [FAQ](https://dummyfilegenerator.com/faq)
- [How it works](https://dummyfilegenerator.com/how-it-works)

## File format references

- [Portable Document Format (.pdf, application/pdf)](https://dummyfilegenerator.com/file-formats/pdf)
- [JPEG Image (.jpg, image/jpeg)](https://dummyfilegenerator.com/file-formats/jpg)
- [Portable Network Graphics (.png, image/png)](https://dummyfilegenerator.com/file-formats/png)
- [JavaScript Object Notation (.json, application/json)](https://dummyfilegenerator.com/file-formats/json)
- [Comma-Separated Values (.csv, text/csv)](https://dummyfilegenerator.com/file-formats/csv)
- [Extensible Markup Language (.xml, application/xml)](https://dummyfilegenerator.com/file-formats/xml)
- [Plain Text File (.txt, text/plain)](https://dummyfilegenerator.com/file-formats/txt)
- [Microsoft Word Document (.docx, application/vnd.openxmlformats-officedocument.wordprocessingml.document)](https://dummyfilegenerator.com/file-formats/docx)
- [Graphics Interchange Format (.gif, image/gif)](https://dummyfilegenerator.com/file-formats/gif)
- [Web Picture Format (.webp, image/webp)](https://dummyfilegenerator.com/file-formats/webp)
- [MPEG-1 Audio Layer III (.mp3, audio/mpeg)](https://dummyfilegenerator.com/file-formats/mp3)
- [MPEG-4 Part 14 (.mp4, video/mp4)](https://dummyfilegenerator.com/file-formats/mp4)
- [ZIP Archive (.zip, application/zip)](https://dummyfilegenerator.com/file-formats/zip)
- [HyperText Markup Language (.html, text/html)](https://dummyfilegenerator.com/file-formats/html)
- [Cascading Style Sheets (.css, text/css)](https://dummyfilegenerator.com/file-formats/css)

## Optional

- [Worked example: hardening upload validation when extensions lie](https://dummyfilegenerator.com/blog/case-study-mime-sniffing-upload-hardening): A composite, illustrative scenario: a .jpg that is really text crashes a thumbnail worker, a too-strict fix blocks valid photos, and a layered check (magic bytes, then a sandboxed decode) resolves both.
- [Worked example: testing a 5 MB PDF upload limit byte by byte](https://dummyfilegenerator.com/blog/case-study-five-mb-pdf-upload-boundary): A composite, illustrative scenario showing how three exact-size PDF fixtures (5,242,879 / 5,242,880 / 5,242,881 bytes) can expose silent truncation and vague error messages, plus the checks that catch them.
- [Changelog: exact-size PDFs, new formats, Chrome extension, download pages and upload limits](https://dummyfilegenerator.com/blog/changelog-magic-byte-lab-scenarios): What changed on Dummy File Generator and how to use it: valid exact-size PDFs, DOCX/ZIP/WebP output, a Chrome extension, ready-made /download test-file pages, an /upload-limits reference, and the earlier magic-byte and scenario tools.
- [Three Ways to Get Test Files: Hosted Samples, Browser Generators and CLI Tools](https://dummyfilegenerator.com/blog/compare-dummy-file-generators-privacy): A fair comparison of downloading hosted sample files, generating files in the browser, and making them with truncate, fallocate, dd or mkfile: exact sizes, format validity, data flow, reproducibility and CI use.
- [Testing Image Compression and Resizing Features](https://dummyfilegenerator.com/blog/testing-image-compression-resizing): A test set for image upload pipelines: EXIF orientation, GPS stripping, transparency, CMYK, huge dimensions, animation and size limits. With ImageMagick and exiftool commands to build each input and checks for each output.
- [What is a Polyglot File? (Security Testing Guide)](https://dummyfilegenerator.com/blog/polyglot-files-security-testing): A polyglot is one file that is valid as two formats at once, so it passes a magic-byte check as one type and is read as another. Why formats allow this, how to build a harmless probe for staging, and the defences that actually work.
- [How to Test File Upload Progress Bars (Network Throttling Guide)](https://dummyfilegenerator.com/blog/testing-upload-progress-bars-throttling): On localhost every upload finishes instantly, so progress bars, cancel buttons and timeouts go untested. How to throttle uploads in DevTools and Playwright, how long a given file should take, and what to check while it runs.
- [Automating File Upload Tests with Playwright, Cypress and Selenium](https://dummyfilegenerator.com/blog/automating-file-upload-tests-selenium-cypress): Working code for setting files on upload inputs in Playwright, Cypress and Selenium, including hidden inputs, drag-and-drop zones, remote grids, and asserting on what the server actually received.
- [Mocking API Responses for Frontend Work: Fixtures, MSW and Oversized Payloads](https://dummyfilegenerator.com/blog/mocking-data-api-development): A practical setup for building a frontend before the API exists: schema-checked JSON fixtures, Mock Service Worker handlers for every UI state (including slow, huge and failed uploads), and Playwright route mocks for tests.
- [How to Generate Large Test Files without Crashing Your Browser](https://dummyfilegenerator.com/blog/generate-large-test-files-browser): How a browser builds a large file (a typed array, a Blob and an object URL), where the memory goes, why this site generates on the main thread and caps files at 512 MiB, and what to use when you need gigabytes.
- [The Importance of Mime-Type Validations in Security Testing](https://dummyfilegenerator.com/blog/importance-of-mime-type-validations): The extension, the Content-Type header and the magic bytes are three different claims about a file, and only one is hard to fake. How each is produced, server-side checks in Node and Python, the formats that have no signature, and a test matrix.
- [Managing Test File Fixtures: Naming, Manifests and Generating Them in CI](https://dummyfilegenerator.com/blog/best-practices-software-testing-dummy-assets): How we keep upload fixtures reproducible without bloating the repository: a naming scheme, a manifest of expected results, and small Node.js helpers that pad JSON and PNG files to exact sizes at test time.
- [TXT, CSV, JSON and PDF Test Files: What Each One Actually Exercises](https://dummyfilegenerator.com/blog/differences-between-file-types): The four most common test file formats hit very different code paths. How each is structured, how it behaves when padded to a target size, and the parser bugs each one is good at finding.
- [Building a File Upload Test Matrix: Partitions, Boundaries and Load](https://dummyfilegenerator.com/blog/how-to-test-systems-with-sample-data): A practical way to turn an upload requirement into a small, complete set of test files: equivalence partitions, boundary values in bytes, a results table, and a k6 script for concurrent uploads.
- [Six Upload Bugs That Only Show Up With Exact-Size Test Files](https://dummyfilegenerator.com/blog/why-developers-need-dummy-files): Grabbing "some big PDF" from your Downloads folder misses the bugs that matter. Six concrete upload failures, how to reproduce each with a dummy file, and what the fix usually looks like.
- [What Is a Dummy File? Anatomy, Byte Sizes and When to Use One](https://dummyfilegenerator.com/blog/what-are-dummy-files): A dummy file is a real, openable file whose contents do not matter but whose type and exact size do. Here is how one is built, how to verify it, and when a real sample is the better choice.
- [Tech glossary](https://dummyfilegenerator.com/glossary)
- [About the author](https://dummyfilegenerator.com/about-us)
- [Full text of this site for LLMs](https://dummyfilegenerator.com/llms-full.txt)