Backend Developer – Consent Enforcement & API Security

1. The Core Rule: No access without logged, verifiable consent All critical functions in the web app — like generating content, unlocking any UI element, or moving through a behavioral stage — must be blocked on the server unless the user has agreed to the legal terms. This agreement must be explicitly collected through the user interface and logged on the backend. Nothing should be unlocked just because the frontend says so. You must treat the client-side as untrusted and enforce everything server-side. The moment a user clicks “Agree” to your Terms of Service, EULA, and Addendum, the backend must record that agreement. From then on, only that user session is allowed to access your product’s gated behavior. Any session that has not gone through this consent process must be rejected outright by your backend. 2. The Clickwrap: How consent is gathered Consent must be gathered using a visual and deliberate UI interaction — not implied by usage or buried in a signup flow. A proper clickwrap must include: An unchecked checkbox or an “I Agree” button that the user must affirmatively click. Visible mention that they are agreeing to the ToS, EULA, and any additional agreements. A direct connection to the specific version of your legal terms in use at the time. Once the user consents, you log the following: The time the consent was given The IP address and device info The version of the ToS/Addendum they agreed to The specific hash of the PDF file that contained those terms (this proves what the user actually saw) This information becomes your proof of consent in case you need to take legal action later. 3. Backend enforcement of consent Your backend must reject any request to use protected features unless it can confirm that consent was logged for the session making the request. That means: If a request comes in to “generate” content, but the session ID was never tied to an agreement, you reject it. If a session tries to start a countdown or move into the generation flow without verified consent, you block it. This blocking must happen at the backend — where the logic cannot be bypassed or altered by modifying the client. If you check consent only on the frontend (for example, with a local variable or cookie), it can be easily bypassed or faked. That’s legally useless. 4. No alternate access routes You must prevent all alternative or hidden ways to trigger protected functionality. Do not build any public endpoints, test routes, debug APIs, or backup links that expose generation, countdowns, or flow triggers. These become liabilities. If someone reverse-engineers your client or watches network traffic, they must not be able to access the underlying logic directly. All functionality must be gated through the proper legal and technical consent process. 5. Tracking violations and abuse You need to log all requests that violate your protection rules. This includes: Requests that attempt to access protected functionality without logged consent Requests from users trying to manipulate tokens or reuse sessions Repeated attempts from the same IP address to force access or brute force your system 6. Legal enforceability depends on structure If you collect real consent through clickwrap, log it with identity markers (like IP, timestamp, session ID), and block all usage unless that consent is verified server-side — then you can legally enforce your terms. If a user bypasses this and copies your behavioral UX or simulates your flow, you have proof: That they entered through your platform That they agreed to your restrictions That they violated them Here's the technical explanation: 1. Clickwrap Enforcement (Frontend → Backend Consent Logging) Frontend (React/Vue/HTML): Modal before ANY protected interaction (AI generation, etc.). Checkbox (unchecked by default) + “Agree & Continue” button. Summary: “I agree to the Terms of Service, EULA, and Addendum A governing the UX structure and legal use of this platform.” Threat Vectors and How to Block Them Bypassing UI via direct API access All protected routes must enforce verified user consent. Any request skipping UI must be authenticated through server-enforced checks. Manual replay of requests Use short-lived JWT session tokens to make old requests expire quickly and prevent reuse. Client-side state manipulation Never trust client-side inputs. Only accept actions that match a valid server-side record. Observation and mimicry of actions Prohibit simulated behavior in your terms of service. Use detailed logs and session fingerprinting to detect and prove breaches. 2. Server Middleware – Consent Gatekeeping Every backend API route must block execution unless valid consent is found. 3. Token-Based Consent (Optional Hardening) Generate a JWT token after valid clickwrap. Sign it server-side. 4. Abuse Detection and Rate-Limiting Build logs and logic for: Access attempts to /api/generate without valid consent Rapid repeat attempts from single IP (rate limit & block) Requests made with expired or tampered tokens Mismatched UI + API behavior (bypassing front-end constraints) Store and cluster suspicious sessions for potential legal escalation. For more on how it should look in the code, please open the attached PDF. Apply Job! Apply to this Job