Random Test File Generator
Create and download a test file at a selected byte size for upload limits, storage checks and application testing.
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Random Test File Generator
Creates a downloadable binary file of the requested positive size in bytes, KiB or MiB, with a hard in-memory limit of 64 MiB.
The bytes are filled locally with crypto.getRandomValues in chunks no larger than 65,536 bytes, matching the browser API limit.
The default name is random-file.bin. Changing the filename changes only the download label; content remains arbitrary bytes with binary MIME type.
Generation holds the byte array and Blob in browser memory, so large values can briefly use more memory than the final file size.
The file may support transfer and storage tests, but this page does not derive keys, verify entropy provenance or create an extension-specific format.
The selector labels use binary sizes: KiB = 1,024 bytes (KiB), MiB = 1,048,576 bytes (MiB). Allowed requested size is 1–67,108,864 bytes; fractional byte results are rounded down. Set the filename before generation, generate, then click Download results; downloading is not automatic. A local Blob download does not measure internet transfer speed.
Processing takes place locally in your browser.