Daily Note: TIL — Polly SSML <mark> tags
Polly's SSML <mark> tags emit timing events over the stream. Useful for synchronizing on-screen captions to voice playback.
TIL: Polly's <mark> SSML tags surface as timing events in the audio stream. If you're doing voice + screen-pop, you can synchronize captions to the exact word.
<speak>
Please hold while I <mark name="lookup"/> look up your account.
</speak>
On the consumer side, you subscribe to the mark events and flip UI state when lookup fires. This is the missing piece I needed for a low-latency voice+visual experience I've been prototyping.
Docs: Amazon Polly → "SpeechMarks" → JSON event with time and value.
Written by
Adrian Romo
Senior Backend Engineer building scalable Python APIs, AWS Lambda architectures, voice systems, and enterprise integrations.
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