SampleTestFiles is a free library of sample files for people who build and test software. Every file exists for one reason: so that you can check what your application does with a file of a known type and an exact size, without hunting for one or exposing a real document.
What you will find here
- Sized samples. Valid files in common formats, each built to an exact byte count: a 10 MB PDF is 10,485,760 bytes, a 1 KB PNG is 1,024 bytes.
- Curated samples. Realistic documents and deliberately awkward files: quoted CSV fields, a zero-byte file, names with spaces and non-ASCII characters, a transparent PNG, a multipart email.
- Reference pages. For each format, its MIME type, signature bytes, structure and the mistakes software commonly makes with it.
- Guides. Practical instructions for testing uploads, downloads, size limits and type validation, with working code.
Downloads are direct. There is no account, no email form and no countdown.
How the files are made
We do not collect files from the internet. Every sample is produced by our own generator, which writes each format from its published specification and then checks the result. That has three consequences that matter to you:
- No personal data. Names, addresses and companies in the files are invented. Email addresses use the reserved example.com domains.
- No hidden content. There are no macros, scripts, trackers or embedded executables in any file.
- Reproducible bytes. The generator is deterministic, so a file has the same content and the same SHA-256 checksum every time the site is built. The checksum is printed on each download page.
Where a file needs padding to reach an exact size, the download page says how much and where it is. Padding always uses a mechanism the format itself provides, such as a comment field, never junk appended to the end.
Our file safety page describes this in more detail.
How quality is kept up
- A file is published only if it is exactly the stated size, begins with the correct signature for its format and parses as that format.
- A page is created only where a real file exists. Sizes that cannot be produced as a valid file are left out.
- Pages that add little beyond their format page are kept out of search engines, so that what is indexed is worth finding.
- Guides and reference pages are written for this site. Nothing is copied from other websites.
Who it is for
Developers writing upload handlers and parsers. Testers building a kit of fixtures. Engineers checking a CDN, a proxy limit or a pipeline step. Students learning how file formats work. If you have ever typed "10 MB test file" into a search engine, this site is for you.
How the site is funded
SampleTestFiles is free to use and is supported by advertising. Advertisements are labelled, kept apart from download buttons and never styled to look like them. We do not accept payment to recommend tools or to alter the content of guides.
Accuracy
Format details are checked against the specifications linked from each page, and default limits quoted in the guides are checked against the documentation of the software concerned. Software changes, so if you find something out of date, please tell us. Corrections are welcome and are usually made quickly.
Contact
You can reach us at contact@sjwebtechwork.com or through the contact page.