Generate 1 KB to 10 MB of repeated test data. Three output formats for testing form fields, API payloads, database columns, and upload limits.
Unlike the other repeaters that count repetitions, this tool generates output to an exact byte size — 1 KB, 10 KB, 100 KB, 1 MB, or 10 MB. Useful when you're testing:
client_max_body_size or similar.1., 2., etc. Useful for debugging which line caused a failure.For pure ASCII patterns ("qwerty", numbers, English letters), the byte size equals the character size. If you use multi-byte characters (emojis, accented characters, CJK), the actual byte size in UTF-8 will be larger than the displayed character count. For accurate byte sizes, stick with ASCII.
Sometimes you just need a known-size file to upload, paste, or send via API — without writing a one-off script. This tool is faster than spinning up a Python REPL for a one-time task.
Exactly 1 MB (1,048,576 bytes for ASCII patterns). The tool pads or truncates the final repetition to hit the target size precisely.
10 MB. Beyond that, browser memory and clipboard handling become unreliable. For larger test data, generate the file with a script: python -c "print('a' * 100000000)" > test.txt
Most modern browsers handle 10 MB clipboard writes, but it can be slow. For large outputs, use the Download button instead — it streams directly to a file without going through the clipboard.
Repeat WhatsApp messages with one-tap send.
Build emoji walls for chats and posts.
Single-word repetition, optimized.
Repeat each line of multi-line input.
Single character to exact byte counts.
Paragraphs for design mockups.
The technical claims on this page are based on primary specifications and vendor documentation. Last verified 13 July 2026.
Unlike the repeaters that count repetitions, the stress test generator targets an exact byte size — 1 KB, 10 KB, 100 KB, 1 MB, or 10 MB — and pads or truncates the final piece to hit it precisely. That makes it the right tool when what matters is the size of the payload rather than how many times something repeats.
Submit 1 MB of text into a form field to see what breaks; send a payload just over your server's limit to confirm it returns a clean 413 Content Too Large instead of failing in an interesting way; insert a maximum-length value into a database column to check for truncation; or benchmark a parser by feeding it predictably-sized input and measuring how run time scales. The testing guide walks through these cases.
Three layouts — exact, line-broken, and numbered — let you match the shape your test expects. The ceiling is 10 MB, beyond which browser memory and clipboard handling become unreliable; for larger fixtures, generate the file from a short script. For counting repetitions of a single character instead of hitting a byte target, use the character repeater.