Platform
Access control, webhooks, and background tasks.
Platform covers what every integration needs regardless of which product it uses: who can call the API and with what permissions, how to subscribe to webhooks so your integration reacts to changes in real time instead of polling, and how to follow background tasks. The API reference also covers your business profile, configuration defaults, and the fees Penny charges.
Start with Access Control for how permissions work, then Webhooks Overview for how to receive real-time events.