Yes, in two ways. First, every account can generate Developer API keys (up to 10 per account) that let you or your developer create and manage links, QR codes, domains, and more from custom code or scripts, each key scoped to what it's allowed to do.
Second, we support OAuth2, the same technology behind "Login with Google" or "Login with Facebook" buttons. This allows registered third-party applications to offer "Login with [our platform]" to their own users, so people can sign in securely using their existing account instead of creating a new one.