A temporary-mail service has several different workloads: generating addresses, listing mail, opening bodies, receiving SMTP traffic and running administrative jobs. A single global limit cannot express all of their risks.
Put cheap checks first
Validate the route, method, input size and required credentials before expensive database or object-storage work. Use bounded caches for suitable metadata and avoid creating unlimited per-key state from unverified identifiers. Access checks still need to apply on cached responses.
Budget each workload
| Workload | Useful control |
|---|---|
| Anonymous inbox polling | Request budgets, backoff guidance and session validation. |
| Authenticated API use | Limits associated with the credential and operation. |
| SMTP ingestion | Connection, message-size and recipient-work limits. |
| Maintenance jobs | Small batches and bounded concurrency. |
Distinguish a burst from continued abuse
A legitimate client can retry after a network failure. Record enough information to distinguish that burst from sustained traffic that ignores limits. Graduated responses may include slowing requests, temporary rejection or credential revocation when the evidence and policy justify it.
Verify the failure path
Test that a rejected request does not still perform the expensive work. Confirm that well-behaved clients understand retry responses and that privileged inbox access cannot be bypassed by changing the endpoint.
This is an architectural checklist, not a claim that every control is enabled on every deployment. Current service limits and access rules should be taken from the site's documentation and API responses.