Batch captcha generation
Generate batches of verification-code images locally in the browser for demonstrations and testing; not for production authentication and does not include a remote verification service.
How to batch-generate verification codes
Verification codes are generated locally by the current browser Canvas; they are not uploaded, keys are not saved, and no remote verification service is provided.
Set seed
Enter a fixed seed or custom text, and set the generation quantity and image dimensions.
Generate preview
Click Generate to view batch results; the same seed, text, and dimensions produce repeatable results.
Download image
Download PNG one by one; if integrating into a service, you must separately implement server-side generation, validation, and replay protection.
Limitations and Notes
- This is an image generator for demonstrations and testing, not a secure verification system, and it cannot stop bots.
- Generate at most 24 images per batch; custom text can be up to 16 characters long. Complex fonts and noise effects are limited.
- Exported images do not include server-side signatures, expiration times, or one-time verification information.
FAQ
Can it be used directly as a login verification code?
No; production authentication must be generated and validated by the server, with replay prevention.
Can the same seed reproduce the result?
With the same text, dimensions, and version, the page will provide deterministic results whenever possible.
Will the generated content be uploaded?
No, drawing and exporting with Canvas are both completed in the current browser.