2y old thread so maybe a new one would be better as V5 is now recently released and a new Dev Agreement published (or a better outlined one.) Speaking of which, the Developer Agreement is a good place to start but there isn’t really a hard limit, the general guideline is 1 call/sec at most - I don’t believe it’s necessarily tracked by IP but rather Client ID (or a conjunction of the two).
Twitch monitors usage and will contact you if it is what they consider excessive.