> ## Documentation Index > Fetch the complete documentation index at: https://quintsecurity.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # System Architecture > Three-tier architecture: ES extension (truth), forward proxy (intent), and the cloud platform. Covers session detection, event ingestion, and the API service. # System Architecture Quint is a three-tier security platform that combines OS-level ground truth (EndpointSecurity system extension), intent-level interception (forward proxy plus MCP gateway), and a cloud platform for fleet-wide visibility. The key security signal is **divergence** between what an agent claims to do and what actually happens on disk. ## Target-state architecture The diagram below is Quint's **enterprise-ready target state** — the north-star topology the platform is converging on. Events flow from an MDM-managed endpoint fleet over the SNS/SQS bus into stream processing and tiered hot/warm/cold storage, with per-tenant egress to customer SIEMs and a dedicated fleet-management plane. Note that the behavioral stream **ranks only and never makes an enforcement decision**. The tiers described in the rest of this page are the **current shipping implementation** this target state builds on. Quint enterprise-ready target-state architecture: MDM-managed endpoint fleet, SNS/SQS event bus, behavioral/alerts/pipeline stream processing, hot/warm/cold storage tiers, per-tenant egress, and fleet management plane. ## Three-Tier Architecture ```mermaid theme={null} flowchart TD subgraph T1["Tier 1: Edge (macOS pkg)"] ES["EndpointSecurity Extension (Swift)
9 event types, code-signing detection"] NE["Network Extension (Swift)
Transparent LLM API interception"] Daemon["Go Daemon
LaunchDaemon service"] FwdProxy["HTTPS Forward Proxy
MITM TLS, 7 LLM parsers"] MCPGateway["MCP Gateway and Stdio Relay"] UniSession["Unified Session Tracker
process scanner, PID reaper"] Forwarder["Cloud Forwarder
batch 500, 1s flush, overflow-to-disk"] ES -->|Unix socket + auth| Daemon NE -->|Unix socket :9091| Daemon FwdProxy --> Daemon MCPGateway --> Daemon Daemon --> UniSession Daemon --> Forwarder end subgraph T2["Tier 2: Cloud Platform (AWS ECS)"] Ingest["Ingest Service
/v1/ingest, deploy-token auth"] SNS["SNS FIFO + SQS fan-out"] Pipeline["Pipeline Service
Postgres writer, monthly partitions"] SessionProc["Session Processor
upserts sessions table"] AlertProc["Alert Processor
rule evaluation"] API["API Service
REST + SSE"] PG[("PostgreSQL
RLS, monthly partitions")] Redis[("Redis
token cache, SSE pubsub")] Forwarder -->|HTTPS batch| Ingest Ingest --> SNS SNS --> Pipeline SNS --> SessionProc SNS --> AlertProc Pipeline --> PG SessionProc --> PG AlertProc --> PG API --> PG API --> Redis end subgraph T3["Tier 3: Dashboard (Vercel)"] Dashboard["Next.js app
session-centric views"] API --> Dashboard end style T1 fill:#1a1a2e,stroke:#FF3C22,stroke-width:2px style T2 fill:#1a1a2e,stroke:#58a6ff,stroke-width:2px style T3 fill:#1a1a2e,stroke:#a371f7,stroke-width:2px ``` ### Tier 1: Edge Runs on the user's machine as a signed `.pkg` install. * **QuintAgent.app** hosts two system extensions: * [Endpoint Security](/edge/endpoint-security) for kernel-level process and file events * [Network Extension](/edge/network-extension) for transparent LLM API interception * **Go daemon** runs as a LaunchDaemon. It operates the [forward proxy](/edge/forward-proxy) (MITM TLS plus MCP relay/gateway), the [unified session tracker](/edge/daemon), and the cloud forwarder. Events stream to `api.quintai.dev` via HTTPS. * **Audit log** at `~/.quint/quint.db` with Ed25519 signatures and SHA-256 hash chaining. Every captured request, response, and tool call is attributable to a specific session. ### Tier 2: Cloud Platform Deployed on AWS ECS Fargate. Five services share one Postgres instance and one Redis cache: | Service | Role | | ----------------- | -------------------------------------- | | ingest | Authenticate, validate, fan out to SNS | | pipeline | Consume SQS, write `actions` table | | session-processor | Upsert `sessions` table | | alert-processor | Evaluate rules, write `alerts` | | api | Dashboard and public API | Row-level security is enabled on all tenant tables using `app.current_org_id`. The `actions` table is partitioned by month. See [Cloud Overview](/cloud/overview) for the full model. ### Tier 3: Dashboard Next.js on Vercel. Reads from the API service over Supabase JWT or API key. Session-centric views with drill-down into each action. See [Dashboard Architecture](/dashboard/architecture). ## Signal: Intent vs. Truth The proxy sees what the agent **claims** to do. The ES extension sees what the OS **actually** does. Divergence is the high-confidence signal. Example: an agent that says "read `config.json`" but actually opens `~/.ssh/id_rsa`. Tier 1 captures the tool call. Tier 2 captures the file open. The mismatch triggers an alert. ## End-to-End Flow See [How It Works](/concepts/how-it-works) for a single tool call traced through all layers. ## Deployment Topology ### Production (AWS) | Service | Resources | Purpose | | ----------------- | --------------------- | -------------------------------------- | | API Service | ECS Fargate | REST API, event ingest | | Ingest | ECS Fargate | Token auth, validation, fan-out | | Pipeline | ECS Fargate | SQS consumer, Postgres writer | | Session Processor | ECS Fargate | Session lifecycle upserts | | Alert Processor | ECS Fargate | Rule evaluation | | PostgreSQL | RDS t4g.medium | Events, sessions, partitioned by month | | Redis | ElastiCache t4g.micro | L1 cache, rate limiting, SSE pubsub | | ALB | Elastic Load Balancer | HTTPS termination with ACM certificate | Infrastructure is fully Terraformed under `quint-platform/infra/terraform/environments/prod/`. ### Endpoint (macOS) | Component | Footprint | Purpose | | -------------- | ------------------ | ---------------------------------- | | QuintAgent.app | \~20MB disk | Container for system extensions | | ES Extension | \~50MB RAM steady | OS-level event capture | | NE Extension | \~40MB RAM steady | Transparent network interception | | Go Daemon | \~100MB RAM steady | Proxy, session tracking, forwarder | | Local SQLite | 10-100MB | Signed audit log (rolling) | ## Security Properties Source code content, credentials, and full LLM conversation bodies never leave the machine. Only structured metadata (tool name, capability, risk decomposition) goes to the cloud. * **Audit log tampering:** Ed25519 signature per row, chained by `prev_hash`. A single modification breaks the chain. * **TLS MITM:** per-hostname leaf certs signed by a local CA that never leaves the machine. * **Cloud auth:** deploy tokens are SHA-256 hashed in Redis, JWT for dashboard users. * **Tenant isolation:** Postgres RLS on every tenant table, SNS/SQS FIFO ordering per session. ## Design Principles 1. **Local-first capture, cloud-first scoring.** Raw bodies stay on the machine. Normalized events flow to the cloud. 2. **Lossy at the edge, durable in the cloud.** Under backpressure, the edge drops events rather than block user traffic. The cloud retries. 3. **Zero client changes where possible.** Forward proxy plus NE means no SDK integration, no new endpoints. 4. **Session-centric model.** Everything anchors to sessions, not raw events. Audit rows, cloud events, and dashboard views all join on `session_id`. 5. **Code signing first.** Agent detection uses macOS code signing as the highest-confidence signal, falling back to process name and path matching only when signing data is unavailable. 6. **Tenant isolation at every layer.** Deploy tokens are scoped to organizations. Postgres uses monthly partitions with row-level security. Cloud queues use FIFO ordering keyed by session.