All answers
Can I tell if a Twitch channel is live?
The profile route returns live-oriented fields on the public card when Twitch exposes them (for example isLive and current viewer count). Use that for enrichment and roster checks. For low-latency go-live webhooks, use Twitch EventSub directly.
Read more
This answer comes from Twitch data API, which covers the full detail, endpoints and pricing in credits.