While TokBox server infrastructure can manage a virtually unlimited number of concurrent sessions and participants, the number of participants in each session is limited by client-side bandwidth, device, and CPU limitations for processing vast amounts of video and audio streams.
Number of participants supported in an OpenTok session would depend on the session topology.
In a Multi-party video session each participant would publish their own stream to the platform, and subscribe to video streams from other participants. For multi-party video session, we can support OpenTok cloud can support up to 50 to 55 participants. Please note that this number would be severely limited by the ability of your end-device to receive, decode and render 50 streams simultaneously.
For a Broadcast session, you will have one or a few participants publishing the stream and the viewers of the broadcast would only be subscribing to that stream. Hence for a session with broadcast topology you need to consider both the total number of publishers and the total number of subscribers. For each publisher, count the number of subscribers it has, and sum up this count over all publishers. This value should then be no more than 3000. As a general guideline, you can think of the following constraint as holding true for broadcast sessions:
(number of publishers) X (number of subscribers) <= 3000