Test / Dummy File Generator
Generate dummy files of an exact byte size — TXT, CSV, JSON, XML, HTML, PNG (solid color), binary, ZIP (real archive), or PDF. Bulk generate with {n} naming patterns. Random / zeros / lorem / pattern content. All client-side via Blob — nothing uploaded.
About Test / Dummy File Generator
Generate dummy files of an exact byte size — TXT, CSV, JSON, XML, HTML, PNG (solid color), binary, ZIP (real archive), or PDF. Bulk generate with {n} naming patterns. Random / zeros / lorem / pattern content. All client-side via Blob — nothing uploaded. Everything runs locally in your browser — your data never leaves your device.
How to use
- Enter your input in the tool above.
- Adjust any options to your preference.
- Use the Copy or Download buttons to save the result.
- Everything happens locally — your data never leaves your browser.
FAQ
How does the dummy file generator work?
Pick a target size (bytes / KB / MB / GB), a file type, and a content mode. We generate the file in-browser with exact byte precision using TextEncoder (text formats), typed arrays (binary), and minimal valid file headers (PNG / ZIP / PDF). The file is downloaded instantly via Blob — nothing is uploaded to a server.
Which file types are supported?
Nine: TXT (plain text), CSV (random table), JSON (nested object with a long string field), XML (root + items), HTML (basic page), PNG (solid color image — a real, openable PNG file padded with tEXt chunks), binary (raw bytes), ZIP (a real ZIP archive with one inner file), and PDF (a minimal valid PDF padded with a comment line). Each format honors the exact requested byte count.
What content modes are available?
Four: random (PRNG-seeded pseudo-random bytes), zeros (all 0x00 bytes), lorem (Lorem Ipsum text), and pattern (your own byte/character pattern repeated). The seedable mulberry32 PRNG lets you reproduce identical files across runs — useful for golden-master tests.
Are my generated files uploaded anywhere?
No. All generation runs locally in your browser using Uint8Array and Blob. The file never leaves your device. History (last 20 generations) is stored in localStorage on this device only — and only stores metadata (size, type, timestamp), not the file contents. The shareable URL encodes options in the fragment (after #) which browsers never transmit.
What extra features does this tool have versus others?
(1) 9 file formats including real PNG/ZIP/PDF. (2) Exact byte-count sizing with B/KB/MB/GB units. (3) 4 content modes (random / zeros / lorem / pattern). (4) Seedable reproducibility (mulberry32 + FNV-1a). (5) Bulk generation (1–100 files) with {n} naming pattern. (6) Configurable PNG color (hex) and dimensions. (7) CSV rows/cols control. (8) SHA-256-style checksum display (computed locally). (9) Bulk ZIP download of multiple generated files. (10) localStorage history (max 20). (11) Shareable-URL config. (12) Download speed estimator.
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