Best Free LLM Routers

OpenRouter is a unified interface for LLMs. OpenRouter scouts for the lowest prices and best latencies/throughputs across dozens of providers, and lets you choose how to prioritize them. No need to change your code when switching between models or providers. You can even let users choose and pay for their own. Evals are flawed; instead, compare models by how often they're used for different purposes. Chat with multiple at once in the chatroom. Model usage can be paid by users, developers, or both, and may shift in availability. You can also fetch models, prices, and limits via API. OpenRouter routes requests to the best available providers for your model, given your preferences. By default, requests are load-balanced across the top providers to maximize uptime, but you can customize how this works using the provider object in the request body. Prioritize providers that have not seen significant outages in the last 10 seconds.

The developer platform for AI characters. Get a fully integrated platform for AI characters that goes beyond large language models (LLMs), and adds configurable safety, knowledge, memory, narrative controls, multimodality, and more. Craft characters with distinct personalities and contextual awareness that stay in-world or on brand. Seamlessly integrate into real-time applications, with optimization for scale and performance built-in. Optimized for real-time experiences, Inworld offers low-latency interactions that scale with your application. Orchestrating across LLMs allows us to deliver high-quality interactions with faster inference and lower costs. Every interaction has a context and models need to be aware of yours. Add custom knowledge, content and safety guardrails, and narrative controls to keep your AI in character, in-world, or on brand. Put personality at the center of your AI. Our multimodal AI mimics the full range of human expression.

Explore the power of choosing the right LLM for your needs and how to optimize for quality, speed, and cost-efficiency. Access all LLMs across all providers with a single API key and a standard API. Setup your own cost, latency, and output speed constraints. Define a custom quality metric. Personalize your router for your requirements. Systematically send your queries to the fastest provider, based on the very latest benchmark data for your region of the world, refreshed every 10 minutes. Get started with Unify with our dedicated walkthrough. Discover the features you already have access to and our upcoming roadmap. Just create a Unify account to access all models from all supported providers with a single API key. Our router balances output quality, speed, and cost based on user-specific preferences. The quality is predicted ahead of time using a neural scoring function, which predicts how good each model would be at responding to a given prompt.

Call the right model at the right time with the world's most powerful AI model router. Make the most of every model with relentless precision and speed. Not Diamond works out of the box with no setup, or train your own custom router with your evaluation data and benefit from model routing optimized to your use case. Select the right model in less time than it takes to stream a single token. Efficiently leverage faster and cheaper models without degrading quality. Program the best prompt for each LLM so you always call the right model with the right prompt. No more manual tweaking and experimentation. Not Diamond is not a proxy and all requests are made client-side. Enable fuzzy hashing on our API or deploy directly to your infra for maximum security. For any input, Not Diamond automatically determines which model is best suited to respond, delivering a state-of-the-art performance that beats every foundation model on every major benchmark.

Vercel AI Gateway is a unified AI infrastructure platform that allows developers to access, manage, and route requests across hundreds of AI models and providers through a single API interface. Built as part of the Vercel AI ecosystem, the platform supports text, image, and video generation models from providers such as OpenAI, Anthropic, xAI, and others while simplifying authentication, billing, observability, and failover management. Developers can use one API key and centralized dashboard to integrate multiple AI providers into applications without managing separate provider accounts or infrastructure. The platform also includes built-in routing, automatic failovers, usage tracking, unified billing, and compatibility with SDKs such as the Vercel AI SDK, enabling faster development and more resilient AI-powered applications.

​LiteLLM is a versatile platform designed to streamline interactions with over 100 Large Language Models (LLMs) through a unified interface. It offers both a Proxy Server (LLM Gateway) and a Python SDK, enabling developers to integrate various LLMs seamlessly into their applications. The Proxy Server facilitates centralized management, allowing for load balancing, cost tracking across projects, and consistent input/output formatting compatible with OpenAI standards. This setup supports multiple providers. It ensures robust observability by generating unique call IDs for each request, aiding in precise tracking and logging across systems. Developers can leverage pre-defined callbacks to log data using various tools. For enterprise users, LiteLLM offers advanced features like Single Sign-On (SSO), user management, and professional support through dedicated channels like Discord and Slack.

Pruna uses generative AI to enable companies to produce professional-grade visual content quickly and affordably. By eliminating the traditional need for studios and manual editing, it empowers brands to create consistent, customized images for advertising, product displays, and digital campaigns with minimal effort.

LangDB offers a community-driven, open-access repository focused on natural language processing tasks and datasets for multiple languages. It serves as a central resource for tracking benchmarks, sharing tools, and supporting the development of multilingual AI models with an emphasis on openness and cross-linguistic representation.

LLM Gateway is a fully open source, unified API gateway that lets you route, manage, and analyze requests to any large language model provider, OpenAI, Anthropic, Gemini Enterprise Agent Platform, and more, using a single, OpenAI-compatible endpoint. It offers multi-provider support with seamless migration and integration, dynamic model orchestration that routes each request to the optimal engine, and comprehensive usage analytics to track requests, token consumption, response times, and costs in real time. Built-in performance monitoring lets you compare models’ accuracy and cost-effectiveness, while secure key management centralizes API credentials under role-based controls. You can deploy LLM Gateway on your own infrastructure under the MIT license or use the hosted service as a progressive web app, and simple integration means you only need to change your API base URL, your existing code in any language or framework (cURL, Python, TypeScript, Go, etc.)

TensorBlock is an open source AI infrastructure platform designed to democratize access to large language models through two complementary components. It has a self-hosted, privacy-first API gateway that unifies connections to any LLM provider under a single, OpenAI-compatible endpoint, with encrypted key management, dynamic model routing, usage analytics, and cost-optimized orchestration. TensorBlock Studio delivers a lightweight, developer-friendly multi-LLM interaction workspace featuring a plugin-based UI, extensible prompt workflows, real-time conversation history, and integrated natural-language APIs for seamless prompt engineering and model comparison. Built on a modular, scalable architecture and guided by principles of openness, composability, and fairness, TensorBlock enables organizations to experiment, deploy, and manage AI agents with full control and minimal infrastructure overhead.

OrcaRouter is an OpenAI-compatible AI model router that sends each prompt to the right model across OpenAI, Anthropic, Gemini, DeepSeek, Qwen, Kimi, and 200+ frontier and open source models. It is built to preserve frontier answer quality while reducing AI inference spend by grading every prompt and routing hard reasoning to frontier models and routine work to lower-cost open source models. The routing is quality-graded, never a blind, cheap-model swap, and each request shows the difficulty grade, selected model, provider, and cost so routes are visible, auditable, and reproducible. Developers can switch by changing the API base URL, while existing SDKs, model names, and streaming behavior continue to work as before. OrcaRouter supports automatic failover, so if a provider goes down mid-stream, traffic can switch transparently, and the application avoids user-facing errors. It also includes API key management with spend caps, model allowlists, rate limits, budget enforcement, and more.

Factory Router is an automatic model-selection system for autonomous software engineering workflows, designed to deliver frontier performance at lower cost and with higher reliability. Instead of expecting engineers to manually choose the best model for every task, Factory Router automatically selects the right model for each Droid session, drawing from a diverse pool of frontier and efficient models. Simple questions, mechanical refactors, documentation updates, small bug fixes, search-heavy investigations, and other routine work can be handled by efficient models, while harder work that genuinely needs deeper reasoning can stay on frontier models. If the selected model struggles to complete a task, Factory Router can move the session to a more capable model to reliably preserve high-quality outcomes. It also routes across models, providers, and capacity sources when endpoints degrade, rate limits hit, or capacity becomes constrained, helping Droid sessions keep working.

OpenRouter Fusion turns a prompt into a small multi-model deliberation, making combined model results as easy to call as a single model. A panel of expert models analyzes the prompt in parallel with web search and web fetch enabled, then a judge model compares their responses and returns structured analysis that includes consensus, contradictions, partial coverage, unique insights, and blind spots. The final answer is written from that analysis, helping users benefit from multiple perspectives rather than relying on one model alone. Fusion is built for cases where a single model is not enough, such as research, expert critique, compare-and-contrast prompts, multi-domain questions, or any task where being wrong is expensive. Users can call Fusion directly through the openrouter/fusion model alias, enable it as the fusion server tool, or configure it through the Fusion plugin; all three entry points use the same pipeline.

TensorZero is an open source LLMOps platform that unifies an LLM gateway, observability, evaluation, optimization, and experimentation. It creates a feedback loop for optimizing LLM applications, turning production metrics and human feedback into smarter, faster, and cheaper models and agents. The gateway lets teams integrate once and access every major LLM provider through a single unified API, including API and self-hosted models, with support for tool use, structured outputs, batch inference, embeddings, multimodal inputs, caching, routing, retries, fallbacks, load balancing, granular timeouts, usage tracking, custom rate limits, and provider-key protection. Built for performance in Rust, TensorZero is designed for extreme throughput and low-latency production workloads while still letting teams adopt only the components they need. Its observability layer stores inferences and feedback in the user’s own database, available programmatically or through the open source UI.

Launch production-ready apps with the LMOps stack for monitoring, model management, and more. Replace your OpenAI or other provider APIs with the Portkey endpoint. Manage prompts, engines, parameters, and versions in Portkey. Switch, test, and upgrade models with confidence! View your app performance & user level aggregate metics to optimise usage and API costs Keep your user data secure from attacks and inadvertent exposure. Get proactive alerts when things go bad. A/B test your models in the real world and deploy the best performers. We built apps on top of LLM APIs for the past 2 and a half years and realised that while building a PoC took a weekend, taking it to production & managing it was a pain! We're building Portkey to help you succeed in deploying large language models APIs in your applications. Regardless of you trying Portkey, we're always happy to help!

Manifest is a Backend-as-a-Service (BaaS) designed to accelerate app development by simplifying the backend part. With a focus on developer efficiency, Manifest allows developers to get a complete backend that fits into only 1 YMAL file, enabling teams to go from idea to deployment faster. It integrates seamlessly with any front-end and scales effortlessly. Built with flexibility in mind, Manifest supports multiple use cases, from MVPs to production-grade applications. Developers can focus on building projects while Manifest takes care of the backend.

Developed by LM-SYS, RouteLLM is an open-source toolkit that allows users to route tasks between different large language models to improve efficiency and manage resources. It supports strategy-based routing, helping developers balance speed, accuracy, and cost by selecting the best model for each input dynamically.

BaronRouter is an AI gateway and chat platform that brings many leading AI models and providers into one unified interface. Users can chat with different models, compare responses side by side, save prompts, create projects, use public personas, upload files, and keep conversation history in one place. BaronRouter is built around reliability and model choice. Its smart router can select a suitable model for a task, while automatic retry and fallback help keep conversations working when a provider is rate-limited, unavailable, or fails. The platform also includes persistent memory, shared workspaces, prompt and persona galleries, model performance stats, admin controls, usage analytics, and an OpenAI-compatible public API for developers. Developers can call BaronRouter through standard OpenAI SDK clients, including support for public persona endpoints such as persona-based chat completions.

flo2 is an LLM gateway and router that provides access to major AI model providers (OpenAI, Anthropic, Groq, Cerebras, DeepInfra) through one unified, OpenAI-compatible API. Smart routing picks the cheapest or fastest model per request. Automatic fallback keeps applications running when a provider goes down. Racing mode runs requests across providers in parallel. Full cost accounting per request, per model, per project. Developers use their own provider keys via flo2.com — RapidAPI's testing tier includes free tokens for evaluation.

UnoRouter is an OpenAI-compatible LLM gateway. One API key gives you 200+ models across providers (OpenAI, Anthropic, Google and more), drop-in for coding agents like Claude Code, Cline, Codex and Kilo Code. Point any OpenAI SDK at the base URL and switch models without changing code. UnoRouter also includes a built-in chat and character client (personas, lorebooks, SillyTavern card import) on the same key. Usage-based pricing with a free tier, live model and price data.

Bifrost is a high-performance AI gateway that unifies access to 20+ providers OpenAI, Anthropic, AWS, Bedrock, Google Vertex, Azure, and more, through a unified API. Deploy in seconds with zero configuration and get automatic failover, load balancing, semantic caching, and enterprise-grade governance. In sustained benchmarks at 5,000 requests per second, Bifrost adds only 11 µs of overhead per request.