CAPTCHA Image Generator
Render CAPTCHA images with noise lines.
🔤CAPTCHA Image Generator
All processing happens locallyWhat this tool does
CAPTCHA Image Generator is a CAPTCHA image renderer drawn on an HTML canvas, implements the standard table both ways and locates invalid bytes instead of silently dropping them.
Characters such as 0/O and 1/I/l are excluded because they are easily confused. More noise lines raise difficulty but also hurt readability. For production, generate and verify CAPTCHAs on the server — client-side images are for demos only.
How to use it
- Paste or type your content into the input field at the top, or press the sample button to load demo data.
- Adjust the options below the input, such as output format, separators, letter case or precision.
- Press the main button to run the conversion. Results appear instantly in the output panel without a page reload.
- When the result looks right, use the copy button in the corner, or download it as a local file.
Tips and notes
Clean up stray spaces and line breaks before pasting for more accurate results.
FAQ
No. The image is only drawn client-side with no matching server-side answer, so production should generate and store the code on the server.
Characters that look alike, such as 0, O, 1, I and l, are removed to avoid misreads; 28 uppercase letters and digits remain.
Yes. Every regeneration draws a new random code, new noise lines and new rotation angles.
The bytes are invalid in the chosen encoding — usually the wrong codec.
Yes. The tool is completely free with no usage limits, and you never need an account or a sign-in.
No. All processing runs locally in your browser, so the input never reaches a server and is never logged or stored.
Yes. The layout is mobile-first, so inputs and buttons stay comfortable on phones and tablets in both orientations.
Yes. A copy button in the output panel puts the result on your clipboard, and you can also download it as a text file.