Here is from the docs:
The Messages & Events quota is a usage‑based quota that tracks every interaction your bot has with a channel:
- All outbound messages the bot sends (e.g., WhatsApp, Webchat, SMS)
- All inbound messages received from users
- Every platform‑generated event such as whatsapp:messageDelivered, whatsapp:messageRead, state_expired, and other internal Botpress events
Botpress aggregates all of these items into a single Messages & Events count. This count is used for billing and quota enforcement – when you approach the limit you’ll receive a warning in the Usage tab, and once the limit is exceeded the bot will stop processing further messages until the quota is refreshed or the plan is upgraded. You can also monitor the current usage in the Usage dashboard, which shows the consumption of this quota alongside other resources.