Software Test Data — free sample and test file generator
Generate genuinely valid sample files in 127 formats at any exact size, from 1 KB to 1 GB. Everything is built in your browser: nothing is uploaded, nothing is stored, and there is no signup or cost.
Choose a format, what goes inside it, and the size you need. Every file is assembled from that format's own specification, so it opens in a real reader rather than merely carrying the right extension.
Each format can also be generated broken on purpose, in three specific ways — invalid, corrupted, or incomplete — so you can test the paths that reject a file as well as the ones that accept it.
What you can control
Size is exact, not approximate: ask for 1,048,576 bytes and that is what arrives, because each format is padded using a mechanism it genuinely permits — a JUNK chunk in a RIFF container, a PADDING block in FLAC, an ancillary chunk in PNG, an entry's extra field in a ZIP package. Formats whose own structure is larger than the size you asked for say so instead of pretending.
Content is chosen per format, and only options that mean something in that format appear: records or nested objects for JSON, columns for CSV, sheets and formulas for XLSX, slides for a presentation, a tone or noise or a synthetic voice for audio, a chart or a QR code for an image. Choose several and they combine into one file rather than producing several.
Text formats can be written as UTF-8, UTF-8 with a byte-order mark, or UTF-16 in either byte order — the mismatch behind most import bugs. ZIP archives and PDFs can be password protected. And the download name itself can be awkward on purpose: a Windows reserved device name, a 255-character name, spaces and punctuation, or non-ASCII characters, because most upload failures come from the name rather than the bytes.
Popular formats
PDF test files · JSON test files · CSV test files · XLSX test files · DOCX test files · PNG test files · JPG test files · ZIP test files · XML test files · TXT test files · MP4 test files · MP3 test files · SVG test files · HTML test files · SQL test files