Web Application (and Website) projects can connect your own Stripe and Twilio accounts from the Integrations tab in your project's workspace, letting Button, Hero, CTA, and Pricing blocks trigger a real checkout or send a real text message through your own accounts, not CodeBlock Studio's.
Stripe checkout
Enter your own Stripe secret key and webhook signing secret (found in your Stripe Dashboard), then set a Button/Hero/CTA/Pricing block's action to "Start a Stripe checkout." Payments go straight to your own Stripe account, we never see or hold the money, and Stripe's webhook confirms the payment back to your project.
Twilio SMS
Enter your Twilio Account SID, Auth Token, and the phone number to send from, then set a block's action to send an SMS. This uses your own Twilio account and its own per-message pricing, entirely outside CodeBlock Studio's billing.
Calling your own API endpoints
Separately from Stripe/Twilio, the same blocks can also "Call a webhook," a POST request to any URL, including your own published API project's endpoints (see "Which project type should I choose?" if you haven't built one yet), with an optional API key field so it can call a key-protected endpoint too.
Tip: Both integrations are entirely optional and off by default — nothing is charged or sent through your accounts until you've entered real credentials and wired up a block to use them.