Testing Tools

Form Fuzz Tester

Paste form markup, choose payload generators, then unleash automated fuzzing to uncover validation blind spots—directly from your browser.

Form under test

Provide the form markup you want to exercise. The preview sandbox will intercept submissions and report validation messages back to the log.

Form HTML snippet

<form id="signup-form">
  <fieldset>
    <legend>Join our beta list</legend>
    <label>
      Email
      <input type="email" name="email" placeholder="you@example.com" required />
    </label>
    <label>
      Username
      <input type="text" name="username" minlength="3" maxlength="20" required />
    </label>
    <label>
      Password
      <input type="password" name="password" minlength="8" required />
    </label>
    <label>
      Favourite number
      <input type="number" name="luckyNumber" min="1" max="999" />
    </label>
    <label>
      Bio
      <textarea name="bio" rows="3" maxlength="140" placeholder="Tell us about yourself"></textarea>
    </label>
    <label>
      Country
      <select name="country" required>
        <option value="">Select country</option>
        <option value="us">United States</option>
        <option value="gb">United Kingdom</option>
        <option value="in">India</option>
      </select>
    </label>
    <label>
      <input type="checkbox" name="agree" required />
      I agree to the terms and conditions
    </label>
  </fieldset>
  <button type="submit">Create account</button>
</form>

Tip: Include a single <form> element. Inputs should have name or id attributes.

Live form preview

0 fields

Fuzz configuration

Choose payload categories, number of iterations, and delay between submissions.

Iterations

Number of submissions per fuzz run.

Delay (ms)

Pause between iterations. Increase for heavy forms.

Fuzzing happens entirely in this iframe; no data leaves your browser. When targeting remote endpoints, ensure you have permission and use opt-in environments.

Fuzz log

The latest 150 entries are shown. Export the full log for deeper analysis.

No runs yet. Start the fuzzer to populate logs.

How fuzzing works

Each iteration picks a random value per field from the selected categories. The preview sandbox submits the form, captures validation messages, and reports the result back to the log.

Check the console in the preview devtools to watch actual submission payloads. When testing external endpoints, replace the form action with your test URL.

For production environments, throttle iterations and include server-side rate limiting. Always test responsibly with staging data.