LLM Proxy for Multi-Tenant - SaaS Platform Architecture

Architecture Overview

Application Layer

Tenant A App

API Key: ta_xxx

Tenant B App

API Key: tb_xxx

Tenant C App

API Key: tc_xxx

↓

Multi-Tenant Proxy Layer

Authentication

Tenant identification

Rate Limiting

Per-tenant quotas

Usage Tracking

Billing data

Routing

Model selection

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LLM Providers

OpenAI

gpt-4, gpt-3.5

Anthropic

Claude models

Azure

Azure OpenAI

Core Features

🔐 Tenant Isolation

Complete separation between tenant data, configurations, and usage metrics. Each tenant operates in an isolated environment.

Separate API keys per tenant
Isolated configuration profiles
Independent rate limiting
Dedicated model access controls
Private prompt templates

💰 Usage-Based Billing

Accurate tracking of token usage per tenant with detailed analytics for invoicing and cost allocation.

Real-time token counting
Per-model cost breakdown
Historical usage reports
Budget alerts and limits
Invoice generation data

📊 Centralized Management

Single pane of glass for managing all tenants. Configure policies, monitor usage, and handle incidents centrally.

Admin dashboard for all tenants
Global policy enforcement
Cross-tenant analytics
Unified logging and monitoring
Bulk configuration updates

⚡ Scalable Infrastructure

Architecture designed to handle thousands of tenants with millions of requests without performance degradation.

Horizontal scaling support
Connection pooling per tenant
Distributed caching
Load balancing strategies
High availability design

Isolation Guarantees

Data Isolation

Tenant prompts, responses, and logs are completely isolated. No cross-tenant data leakage is possible at any layer of the architecture.

Rate Limit Isolation

Each tenant has independent rate limits. One tenant hitting limits does not affect other tenants' access to the service.

Configuration Isolation

Model selection, prompt templates, and provider preferences are configured independently per tenant.

Cost Isolation

Billing is accurately attributed to the correct tenant. Shared infrastructure costs are fairly distributed.

Access Isolation

Tenants cannot access or interfere with each other's API keys, models, or configurations.

Compliance Isolation

Data residency and compliance requirements are maintained per tenant. Regional routing ensures regulatory compliance.

Tenant Billing Metrics

Metric	Description	Tracking Level
Input Tokens	Count of tokens in prompts per tenant	Per request, per model
Output Tokens	Count of tokens in responses per tenant	Per request, per model
API Calls	Total number of requests made	Per endpoint
Model Usage	Which models are used by tenant	Per model breakdown
Error Rate	Failed requests per tenant	Per error type
Cache Hits	Saved API calls from caching	Cost savings

Configuration Example

                        Multi-Tenant Proxy Configuration
                    
                        # Multi-tenant configuration example

                        {

                          "tenants": {

                            "tenant_a": {

                              "api_key": "ta_xxx",

                              "providers": ["openai", "anthropic"],

                              "rate_limit": { "requests_per_minute": 100 },

                              "models": ["gpt-4", "claude-3-opus"],

                              "billing_plan": "enterprise"

                            },

                            "tenant_b": {

                              "api_key": "tb_xxx",

                              "providers": ["openai"],

                              "rate_limit": { "requests_per_minute": 50 },

                              "models": ["gpt-3.5-turbo"],

                              "billing_plan": "starter"

                            }

                          }

                        }

🔗 Related Resources

Enterprise Proxy Guide | Rate Limiting Strategies | Cost Optimization | Multi-Model Proxy