AI Platform

Enterprise AI Gateway Architecture

A unified reverse-proxy platform layer enforcing security, multi-provider model routing, semantic caching, token quotas, and audit logging across all enterprise apps.

By Bhavin Mistry, Senior Engineering Manager at Commonwealth Bank Published: 2026-08-10 Last updated: 2026-09-20 11 min read
Table of Contents (9 sections)
SYSTEM TOPOLOGY & DATA FLOW ENTERPRISE SPECIFICATION
Client Application RBAC Context Security & Gateway PII Sanitization Semantic Cache Check Rate & Token Budget Inference & Rerank BM25 + Vector Fusion Cross-Encoder Top-5 Grounded Synthesis Telemetry OpenTelemetry

The Core Problem Solved

Uncontrolled proliferation of direct provider SDK keys, lack of central usage visibility, sudden cloud quota exhaustion, and unmonitored data egress.

When To Deploy This Architecture

Any enterprise organization with more than one team or application consuming commercial or open-source LLM endpoints.

Architectural Components

  • API Gateway Ingress (Kong / Envoy / Custom Reverse Proxy)
  • PII & Secret Redaction Engine (Regex + lightweight NER)
  • Semantic Cache (Redis vector store for exact and near-match queries)
  • Smart Dynamic Router (Cost, latency, and quota-aware fallback)
  • Token Budget & Quota Manager (Per-team cost attribution)
  • Comprehensive Audit Exporter (SIEM & FinOps telemetry)

Data Flow Narrative

Client SDK -> Internal Gateway -> PII Sanitization -> Semantic Cache Check (Return on hit) -> Dynamic Provider Route (Bedrock/Azure/Anthropic) -> Post-response Guardrail -> Audit Log -> Client Return.

Security & Perimeter Control

API keys never leave the secure secret manager; all prompt payloads stripped of credit card, tax file, and social security numbers prior to external dispatch.

Governance & Telemetry

Unified enterprise FinOps dashboard attributing token spend down to specific cost centers and Jira project keys.

Identified Failure Modes & Mitigations

Gateway latency overhead (>40ms); cache poisoning if semantic threshold is too loose; upstream provider outage cascading across fallback endpoints.

Production Code Implementation

Copy-paste ready implementation snippet demonstrating the core architectural boundary logic:

gateway_routes.yaml
# Enterprise AI Gateway Virtual Route Specification
gateway:
  listen: 8443
  tls:
    min_version: TLSv1.3
  routes:
    - path: /v1/chat/completions
      plugins:
        - pii_redactor:
            rules: ["credit_card", "ssn", "tfn", "api_key"]
            action: mask
        - semantic_cache:
            provider: redis-cluster
            threshold: 0.96
            ttl_seconds: 86400
        - rate_limiter:
            per_team_rpm: 120
            token_budget_monthly: 50_000_000
        - dynamic_router:
            primary: aws-bedrock-claude-3-7-sonnet
            fallback_1: azure-openai-gpt-4o
            fallback_2: internal-mistral-large-vpc
            timeout_ms: 12000
        - audit_logger:
            destination: kafka://telemetry.enterprise.internal/llm-spans
Architectural Q&A

Frequently Asked Questions

What are the core capabilities of an Enterprise AI Gateway?
Centralized API key isolation, PII/secret scrubbing, semantic caching via vector DB, multi-provider quota failover routing, and FinOps audit telemetry.
How does semantic caching reduce LLM inference costs?
By calculating vector embeddings of incoming prompts and querying a high-speed cache (like Redis) with a similarity threshold (>0.96), identical or near-duplicate queries are answered in <10ms with zero vendor token spend.
Engineering Resource

The Enterprise AI Production Checklist

A rigorous 50-point engineering, security, and FinOps verification gate before promoting Generative AI and Agentic systems to live enterprise traffic.

Zero spam. Fortnightly dispatches. Unsubscribe anytime.
Author & Engineering Leader

Bhavin Mistry

Senior Engineering Manager at Commonwealth Bank based in Melbourne, Australia. Focusing on enterprise AI architecture, hybrid RAG, agentic reliability, and technology economics.

Connected Tools & Frameworks

Cross-Referenced Production Resources

Methodology

5-Stage Maturity Framework

Stage gates from exploration to hardened multi-region deployment.

Assessment

AI Readiness Diagnostic

Benchmark organizational readiness across 12 operational dimensions.

FinOps

RAG Cost Calculator

Model vector storage, query volume, and caching ROI accurately.