Tags agent1 ai3 api1 auth1 backend2 caching1 cap-theorem1 checkout1 cqrs1 database1 ddd1 dotnet3 fintech3 idempotency2 llm2 load-balancing1 mediatr1 openai1 outbox1 payment1 payments1 prompt2 rag1 rate-limiting1 scalability1 stripe1 system-design1 token1 webhook2