---
title: "AI-Native at the Database Layer: Chat Proxy + Vector Store + Transcribe + SSE"
description: "HeliosDB Full v7.5/v7.6 ships chat proxy, vector store, embeddings, transcribe, SSE, agents, documents, and per-tenant quotas — all behind one Postgres-wire instance. The AI surface that collapses Pinecone + Qdrant + an inference proxy into the engine."
date: 2026-06-02
updated: 2026-06-02
tag: "Architecture"
canonical: https://www.heliosdb.com/blog/ai-native-database-layer-chat-vector-transcribe-sse.html
---

# AI-Native at the Database Layer: Chat Proxy + Vector Store + Transcribe + SSE

HeliosDB Full v7.5 and v7.6 collapsed an entire AI-app middle tier into the database. The chat proxy, vector store, embedding service, transcribe endpoint, SSE streaming, agents/documents/quotas surface — every endpoint a modern AI app expects from a Pinecone-plus-OpenAI-proxy stack — now lives behind one Postgres-wire instance. This post walks through what shipped and how the surface composes.

## The endpoints

v7.5 added Tier 1: chat proxy and vector store.

```
POST /api/v1/chat/completions       # OpenAI-compatible chat proxy
POST /api/v1/embeddings              # model-routed embedding generation
POST /api/v1/vectors/search/hybrid   # BM25 + HNSW hybrid retrieval
```

v7.6 added Tier 2 (agents, documents) and Tier 3 (embeddings as a managed service, transcribe, SSE, quotas):

```
GET  /api/v1/agents/:id/threads      # multi-turn agent state
POST /api/v1/agents/:id/threads/:t   # append message, get streamed response
POST /api/v1/documents               # upload + chunk + embed + store
POST /api/v1/transcribe              # audio → text via routed model
GET  /api/v1/events                  # Server-Sent Events for stream subscription
GET  /api/v1/tenants/:id/quota       # per-tenant token / request budgets
```

## The chat proxy

The chat proxy is OpenAI-compatible: same JSON, same streaming format, same tool-use schema. Behind it, requests fan out to whichever model the tenant's policy routes them to — OpenAI, Anthropic, an on-prem Ollama, a fine-tuned model on a GPU node. The proxy maintains a token budget per tenant (the v7.6 quota module enforces it), logs every request to a CDC stream you can subscribe to, and persists conversation state to the vector-store-backed thread table.

## The vector store and hybrid search

v7.6 wired HNSW into `/api/v1/vectors/search/hybrid` (the perf wave: see ["What Changed in HeliosDB Full Perf"](https://www.heliosdb.com/blog/full-perf-vectorized-comparisons-hnsw-hybrid.html)). The hybrid endpoint accepts a query string + optional vector, computes BM25 over the FTS index, fuses the two ranked lists with RRF, and returns the top-k. Same surface as the SQL `hybrid_search()` table function, but over HTTP for non-SQL clients.

## SSE streaming

SSE was the obvious binding for chat completions and agent threads — it composes cleanly with HTTP/2, every browser supports it natively, and it doesn't require a websocket upgrade dance. The `/api/v1/events` endpoint accepts a query and streams updates as `text/event-stream`. Subscribers get cursor-based deltas; reconnection is handled by the standard `Last-Event-Id` header.

## Transcribe

`POST /api/v1/transcribe` accepts audio bytes, routes to a configured speech-to-text model (Whisper-class), and returns text plus optional segment timestamps. The implementation is intentionally thin — it's a routed proxy, not an embedded model.

## Why it lives in the database

Three reasons. **State.** Chat threads, agent memory, documents, and embeddings all want to live next to the relational data they refer to. Putting the proxy in the database means a chat reply can include a `SELECT` over the user's own rows without crossing a service boundary. **Quotas.** Per-tenant token budgets need to read and write authoritative state — the database is already that state. **Auditability.** Every prompt, every embedding, every transcription becomes a row you can `SELECT` over for compliance.

HeliosDB Full is source-available under SSPL-1.0. Repository: [github.com/dimensigon/HDB-HeliosDB-Full](https://github.com/dimensigon/HDB-HeliosDB-Full).