Two-sided trust, money movement, and UGC. Use with ../security.md, ../api-design.md, and ../pr-review.md.
- Payments and payouts — Idempotent charges and transfers; reconciliation jobs; never log full card data or raw tokens (
../security.md). - Trust and safety — Listings, messaging, and identity: moderation queues, appeals, rate limits, and escalation paths for illegal or harmful content.
- Fraud — Sybil, collusion, refund abuse: risk scoring on hot paths; manual review hooks for high-value or high-risk actions.
- Reputation — Reviews and ratings: integrity (verified transactions), disputes, and GDPR-style erasure where law requires it.
- Discovery — Search and ranking: explainability for support, abuse resistance, and clear data ownership between buyers, sellers, and the platform.