Decisions & Trade-offs

Context: Webhook ingestion needs high throughput and low memory footprint. Python (FastAPI) was initially evaluated.

Decision: We opted for Go at the edge. Python's GIL and async event loop overhead became apparent during synthetic load tests of 5,000+ concurrent webhook deliveries. Go's goroutines allow us to ingest, validate signatures, and dump to the event bus with minimal latency.

Trade-off: This forced a polyglot architecture. Go handles the dumb pipe, Python handles the smart AI parsing, increasing deployment complexity.

Context: Trend towards autonomous AI agents that reply and delete emails on the user's behalf.

Decision: We explicitly rejected autonomous actions. SortMail uses deterministic logic to construct prompts, but execution (sending, scheduling) always requires human confirmation.

Trade-off: Lower automation score on paper, but absolute trust in reality. We prioritize decision clarity over feature count. No silent actions, no hidden automation.

Context: Storing Gmail/Outlook OAuth tokens securely.

Decision: Tokens are encrypted at rest using a rotating master key (KMS). More importantly, the system aggressively expires refresh tokens if inactivity is detected, forcing re-authentication.

Trade-off: Increased user friction if they don't log in frequently. We accept this UX hit to maintain a fortified security posture.