Zapier
Zapier actions and trigger (by invite).
Connect relaybell to thousands of apps with no code. Actions: Send Notification and Track Event; trigger: New Subscriber. You connect it with an API key from Settings → Developers → API keys. Note: relaybell isn't in Zapier's public app directory yet (Zapier is still reviewing it), so searching for it in Zapier won't find it — contact us for an invite link.