CAPTCHA: Audio

Count the beeps in a server-synthesized audio clip and submit the number

What you will learn

Treat an audio captcha as an audio-to-text problem (count beeps / decode tones)
Drive an <audio> element and reason about Web Audio analysis vs a solver service
Submit the decoded value for server-side grading against the signed token

Audio CAPTCHA — Count the Beeps

A server-synthesised WAV plays N beeps. The count is the answer, sealed inside an HMAC token — only audio analysis (or your ears) recovers it

Press play, count how many beeps you hear, then type the number. The audio is generated on the server as raw PCM; the correct count never appears anywhere in the DOM, so a bot cannot scrape it from the page.

Mode: practice — the answer is leaked below so a naive test can pass.

Listen & Answer

How many beeps do you hear?

Testing Tips

Automation hints

✓ An audio CAPTCHA is fundamentally an audio-to-text task — there is no DOM text to read; the beep count lives only in the WAV bytes
✓ Decode #captcha-audio src (data:audio/wav;base64,…), then count amplitude bursts via a Web Audio FFT / RMS-envelope analysis or an external solver service
✓ In ?mode=practice the expected count is leaked in #captcha-answer-hint — read it to make a naive test pass; in ?mode=hard it is withheld
✓ Type the count into #captcha-answer and click #captcha-submit; use #captcha-reload to fetch a fresh beep count (tokens expire ~5 min)
✓ Assert success on #captcha-result[data-verdict=human], not just any result message

Related Challenges

CAPTCHA: Audio

Count the beeps in a server-synthesized audio clip and submit the number

What you will learn

Treat an audio captcha as an audio-to-text problem (count beeps / decode tones)
Drive an <audio> element and reason about Web Audio analysis vs a solver service
Submit the decoded value for server-side grading against the signed token

Audio CAPTCHA — Count the Beeps

A server-synthesised WAV plays N beeps. The count is the answer, sealed inside an HMAC token — only audio analysis (or your ears) recovers it

Mode: practice — the answer is leaked below so a naive test can pass.

Listen & Answer

How many beeps do you hear?

Testing Tips

Automation hints

✓ An audio CAPTCHA is fundamentally an audio-to-text task — there is no DOM text to read; the beep count lives only in the WAV bytes
✓ Decode #captcha-audio src (data:audio/wav;base64,…), then count amplitude bursts via a Web Audio FFT / RMS-envelope analysis or an external solver service
✓ In ?mode=practice the expected count is leaked in #captcha-answer-hint — read it to make a naive test pass; in ?mode=hard it is withheld
✓ Type the count into #captcha-answer and click #captcha-submit; use #captcha-reload to fetch a fresh beep count (tokens expire ~5 min)
✓ Assert success on #captcha-result[data-verdict=human], not just any result message

Related Challenges

CAPTCHA: reCAPTCHA v3

Expert

Network Intercept

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CAPTCHA: Audio

What you will learn

Audio CAPTCHA — Count the Beeps

Listen & Answer

Testing Tips

Timer

Need Help?

Related Challenges

CAPTCHA: reCAPTCHA v3

Network Intercept

Service Worker

CAPTCHA: Audio

What you will learn

Audio CAPTCHA — Count the Beeps

Listen & Answer

Testing Tips

Timer

Need Help?

Related Challenges

CAPTCHA: reCAPTCHA v3

Network Intercept

Service Worker