A comprehensive guide to AI gateways and unified LLM API platforms for developers. Compare top AI gateway solutions, explore integration examples, and simplify your multi-model LLM infrastructure.
An AI gateway (also called an LLM gateway or LLM proxy) is a unified API layer that sits between your application and multiple large language model providers. Instead of integrating separately with OpenAI, Anthropic, Google, Mistral, and others, an AI gateway provides a single endpoint to access all of them.
Key benefits of using an AI gateway:
- Unified API — One SDK and consistent request format across all LLM providers
- Model Fallbacks — Automatically route to backup models when primary providers fail
- Cost Optimization — Compare pricing and route requests to the most cost-effective LLM
- Load Balancing — Distribute traffic across providers to avoid rate limits
- Observability — Centralized logging, monitoring, and analytics for all LLM calls
- Caching — Reduce costs and latency with semantic caching of responses
| Platform | Open Source | Key Strength | Best For |
|---|---|---|---|
| OpenRouter | No | 300+ models, pay-per-use | Startups, indie devs |
| Vercel AI SDK | Yes | Next.js integration, streaming | Frontend developers |
| Portkey | Partial | Observability, enterprise features | Production teams |
| LiteLLM | Yes | Self-hosted, 100+ providers | Cost-conscious teams |
| Kong AI Gateway | Partial | Enterprise API management | Large organizations |
| Cloudflare AI Gateway | No | Edge caching, global network | Performance-focused apps |
OpenRouter is a unified LLM gateway that provides access to 500+ models from OpenAI, Anthropic, Google, Meta, Mistral, and open-source providers through a single API. It offers pay-as-you-go pricing with no monthly minimums, and even provides access to free AI models for experimentation and development.
Code adapted from OpenRouter Quickstart Documentation
import openai
client = openai.OpenAI(
base_url="https://openrouter.ai/api/v1",
api_key="your-openrouter-api-key",
)
response = client.chat.completions.create(
model="google/gemini-3-flash-preview",
messages=[
{"role": "user", "content": "How do I integrate OpenRouter with my Python application?"}
]
)
print(response.choices[0].message.content)The Vercel AI SDK is an open-source TypeScript toolkit for building AI-powered applications and agents. It provides a unified interface for streaming text, generating structured data, and integrating with React, Next.js, Vue, Svelte, and Node.js—making it easy to switch between LLM providers with minimal code changes.
Code adapted from Vercel AI SDK Documentation
import { generateText } from 'ai';
import { anthropic } from '@ai-sdk/anthropic';
const { text } = await generateText({
model: anthropic('claude-sonnet-4-5-20250929'),
prompt: 'How do I integrate the Vercel AI SDK with Next.js?',
});
console.log(text);Portkey is an AI gateway built for production LLM applications. It offers advanced features like automatic retries, fallbacks, load balancing, and detailed observability—all through an OpenAI-compatible API. Portkey connects to 1,600+ models across 45+ providers and includes enterprise features like guardrails and governance.
Code adapted from Portkey Getting Started Documentation
from portkey_ai import Portkey
client = Portkey(
api_key="your-portkey-api-key",
virtual_key="your-anthropic-virtual-key"
)
response = client.chat.completions.create(
model="claude-sonnet-4-5-20250929",
messages=[
{"role": "user", "content": "How do I integrate Portkey with my existing OpenAI code?"}
]
)
print(response.choices[0].message.content)LiteLLM is an open-source LLM gateway that provides a unified interface for 100+ LLM providers. It can be used as a Python SDK or self-hosted as a proxy server, making it ideal for teams that need full control over their AI infrastructure with features like cost tracking, guardrails, and load balancing.
Code adapted from LiteLLM Getting Started Documentation
from litellm import completion
response = completion(
model="gpt-5.2",
messages=[
{"role": "user", "content": "How do I integrate LiteLLM as a proxy server?"}
],
fallbacks=["anthropic/claude-sonnet-4-5-20250929"]
)
print(response.choices[0].message.content)Code adapted from LiteLLM Proxy Documentation
# Start the LLM proxy server
litellm --model gpt-5.2
# Now use it as an OpenAI-compatible endpoint
curl http://localhost:4000/v1/chat/completions \
-H "Content-Type: application/json" \
-d '{"model": "gpt-5.2", "messages": [{"role": "user", "content": "Hello"}]}'Kong AI Gateway extends Kong's enterprise API management platform with AI-specific features. It provides a Universal LLM API to route across multiple providers like OpenAI, Anthropic, Google Gemini, AWS Bedrock, and more—with traffic control, security, governance, and 15+ AI plugins for observability, semantic caching, and prompt guards.
Configuration adapted from Kong AI Gateway Documentation
# kong.yaml - Declarative configuration
_format_version: "3.0"
services:
- name: llm-service
url: https://api.openai.com
routes:
- name: llm-route
paths:
- /chat
plugins:
- name: ai-proxy
config:
route_type: llm/v1/chat
auth:
header_name: Authorization
header_value: Bearer <your-openai-api-key>
model:
provider: openai
name: gpt-5.2Cloudflare AI Gateway leverages Cloudflare's global edge network to provide caching, rate limiting, and analytics for AI applications. It supports 350+ models across providers like OpenAI, Anthropic, Google, and more—reducing costs through response caching and improving latency with edge computing. Connect with just one line of code.
Code adapted from Cloudflare AI Gateway Documentation
import OpenAI from "openai";
const openai = new OpenAI({
apiKey: process.env.OPENAI_API_KEY,
baseURL: "https://gateway.ai.cloudflare.com/v1/{account_id}/{gateway_id}/openai",
});
const response = await openai.chat.completions.create({
model: "gpt-5.2",
messages: [
{ role: "user", content: "How do I integrate Cloudflare AI Gateway with the OpenAI SDK?" }
],
});
console.log(response.choices[0].message.content);This repository is under active development. Planned additions include:
-
/integrations— Detailed setup guides for each LLM gateway platform -
/models— Comprehensive model availability comparison across AI gateways -
/pricing— Cost comparison calculator and LLM pricing breakdowns -
/benchmarks— Latency and performance benchmarks for each gateway -
/examples— Production-ready code samples and starter templates