Unified API platforms and proxies that aggregate multiple LLM providers behind a single endpoint, providing model routing, fallback, caching, rate limiting, cost optimization, and access control.
15 tools compared · Layer 1 · Updated April 29, 2026
Ranked by community traction, recent activity, and popularity.
Respan
Unified LLM API with 200+ models
Respan is a unified AI gateway that provides a single API endpoint to access 250+ LLMs from every major provider including OpenAI, Anthropic, Google, Meta, Mistral, and dozens more. Built for engineering teams that need reliability and flexibility in their AI stack, Respan eliminates vendor lock-in by enabling seamless switching between models without code changes.
OpenRouter
300+ models across 60+ providers via one OpenAI-compatible API
OpenRouter is a unified LLM gateway that routes requests to the best available provider for each model, with a single API key giving access to 300+ models from OpenAI, Anthropic, Google, Meta, Mistral, Cohere, and dozens of smaller providers. It exposes an OpenAI-compatible API, so any existing OpenAI SDK code works unchanged.
Portkey
AI gateway with 200+ models
Bifrost
High throughput
Helicone
LLM observability and monitoring
Stainless
SDK generation
Unify
Martian
Intelligent model routing based on prompt type
Kong AI Gateway
AI traffic management
Apigee AI Gateway
Google Cloud AI traffic management
Requesty
400+ model access
The Token Company
Token compression