The request hit at midnight: lock down each action, not just the whole API. You need Oauth 2.0 action-level guardrails, and you need them fast.
Oauth 2.0 is standard for securing APIs, but most implementations stop at endpoint or route-level authorization. That’s where gaps appear. If your API handles sensitive operations, one token with broad scope can be overkill—and a liability. Action-level guardrails solve this by enforcing permissions on exact operations inside a single endpoint. You don’t just limit access to /transactions; you control access to “create,” “update,” or “delete” separately.
To implement Oauth 2.0 with action-level controls, start by defining scopes that correspond to specific actions. Each scope should be narrow. Token issuance must bind the user or service identity to scopes that represent authorized actions only. At runtime, the API should check the token’s scopes before executing the requested action. Reject requests where the scope doesn’t match the action, even if the route is allowed.