5 posts on Architecture.
The full boxes and arrows behind my portfolio phone number. LiveKit, Deepgram STT, Groq LLM with three tools, Cartesia TTS, and roughly two cents per minute.
The end-to-end architecture of a privacy-preserving RAG at SAP Labs: preprocessing, HNSW retrieval, metadata pre-filter, PII redaction, generation, audit trail.
The LRU state machine is one component. This is the whole vault, Postgres AEAD rows, the Fly.io API, cert handshake, dashboard, and the /metrics endpoint.
The architecture behind the Go client, local socket, encrypted cache, async refresh, vault-outage fallback, and the canary rollout that caught the bugs.
Scrubbing PII at index time destroys recall on any query naming a public entity. Move it downstream. How DeBERTa, HNSW, and a cross-encoder fit under 2s p95.
