# Model Routing

Published articles for Model Routing.

This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles.

## GitHub Copilot's Project HydraFusion Promises Frontier Level Performance Through Multi-Model Routing

DevFeed: [GitHub Copilot's Project HydraFusion Promises Frontier Level Performance Through Multi-Model Routing](<https://devfeed.tech/articles/github-copilot-s-project-hydrafusion-promises-frontier-level-performance-through-multi-model-routing-8929.md>)

Original publisher: [Read original article](<https://www.infoq.com/news/2026/09/github-hydrafusion/>)

Author: Olimpiu Pop

Published: 2026-09-13T06:06:00Z

Content type: news

Language: en

Sources: [InfoQ](<https://devfeed.tech/sources/infoq.md>)

Topics: [GitHub Copilot](<https://devfeed.tech/topics/github-copilot.md>), [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [AI-assisted coding](<https://devfeed.tech/topics/ai-assisted-coding.md>), [Orchestration](<https://devfeed.tech/topics/orchestration.md>)

Tags: [agentic-coding](<https://devfeed.tech/tags/agentic-coding.md>), [ai](<https://devfeed.tech/tags/ai.md>), [ai-ml-data-engineering](<https://devfeed.tech/tags/ai-ml-data-engineering.md>), [benchmarks](<https://devfeed.tech/tags/benchmarks.md>), [development](<https://devfeed.tech/tags/development.md>), [frontier-model](<https://devfeed.tech/tags/frontier-model.md>), [github-copilot](<https://devfeed.tech/tags/github-copilot.md>), [github-hydrafusion](<https://devfeed.tech/tags/github-hydrafusion.md>), [ml-data-engineering](<https://devfeed.tech/tags/ml-data-engineering.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [news](<https://devfeed.tech/tags/news.md>), [orchestration](<https://devfeed.tech/tags/orchestration.md>)

### AI overview

GitHub's Project HydraFusion research preview for Copilot orchestrates multiple models at runtime for coding tasks. Its single, cascade, and critique execution patterns aim to balance task quality, latency, and estimated cost.

### Source excerpt

GitHub's Project HydraFusion is a research preview for GitHub Copilot that enhances coding intelligence through runtime model orchestration. It dynamically assembles execution plans using models from various providers. The system employs three execution patterns based on task complexity. Evaluations indicate that it achieves high task quality while significantly reducing operational costs. By Olimpiu Pop

## Model routing with Google Cloud API Gateway

DevFeed: [Model routing with Google Cloud API Gateway](<https://devfeed.tech/articles/model-routing-with-google-cloud-api-gateway-4201.md>)

Original publisher: [Read original article](<https://developers.googleblog.com/a-unified-api-for-ai-model-routing/>)

Author: Mak Ahmad; Sanjay Pujare

Published: 2026-09-12T11:04:33.891311Z

Content type: article

Language: en

Sources: [Google Developers Blog](<https://devfeed.tech/sources/google-developers-blog.md>)

Topics: [Amazon API Gateway](<https://devfeed.tech/topics/amazon-api-gateway.md>), [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [Google](<https://devfeed.tech/topics/google.md>), [Cloud](<https://devfeed.tech/topics/cloud.md>), [OpenAPI Specification](<https://devfeed.tech/topics/openapi.md>), [Serverless](<https://devfeed.tech/topics/serverless.md>), [Claude](<https://devfeed.tech/topics/claude.md>), [OpenAI](<https://devfeed.tech/topics/openai.md>)

Tags: [ai-gateway](<https://devfeed.tech/tags/ai-gateway.md>), [api-gateway](<https://devfeed.tech/tags/api-gateway.md>), [claude](<https://devfeed.tech/tags/claude.md>), [cloud](<https://devfeed.tech/tags/cloud.md>), [google](<https://devfeed.tech/tags/google.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [models](<https://devfeed.tech/tags/models.md>), [openai](<https://devfeed.tech/tags/openai.md>), [openapi](<https://devfeed.tech/tags/openapi.md>), [serverless](<https://devfeed.tech/tags/serverless.md>)

### AI overview

Google Cloud API Gateway adds model routing in Public Preview, providing a serverless, OpenAI-compatible endpoint that dynamically routes requests to Gemini, Claude, or OpenAI OSS-GPT. Developers can configure routing in OpenAPI specifications, centralize model changes, and separate application authentication from backend model credentials.

### Source excerpt

Google Cloud API Gateway now offers a model routing feature in Public Preview, allowing developers to dynamically route traffic to models like Gemini, Claude, or OpenAI OSS-GPT without hardcoding endpoints or managing open-source proxies. Developers can easily configure these routing rules directly within their OpenAPI 3.x specifications by mapping virtual model names to specific backend targets on a shared host. Once deployed, the Gateway acts as a serverless ingress layer that accepts standard OpenAI-compatible requests, automatically transcodes the payload to the native schema of the target model, and routes the traffic on the fly.

## How Tailscale built a customer-facing model router on AI Gateway

DevFeed: [How Tailscale built a customer-facing model router on AI Gateway](<https://devfeed.tech/articles/how-tailscale-built-a-customer-facing-model-router-on-ai-gateway-751.md>)

Original publisher: [Read original article](<https://vercel.com/blog/how-tailscale-built-a-customer-facing-model-router-on-ai-gateway>)

Author: Susan Aziz

Published: 2026-09-11T04:00:00Z

Content type: article

Language: en

Sources: [Vercel News](<https://devfeed.tech/sources/vercel-news.md>)

Topics: [AI Platform](<https://devfeed.tech/topics/ai-platform.md>), [networking](<https://devfeed.tech/topics/networking.md>), [API keys](<https://devfeed.tech/topics/api-keys.md>)

Tags: [ai-gateway](<https://devfeed.tech/tags/ai-gateway.md>), [ai-models](<https://devfeed.tech/tags/ai-models.md>), [api](<https://devfeed.tech/tags/api.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [sandbox](<https://devfeed.tech/tags/sandbox.md>), [security](<https://devfeed.tech/tags/security.md>), [vercel](<https://devfeed.tech/tags/vercel.md>)

### AI overview

Tailscale describes using Vercel AI Gateway and Sandbox to deliver customer-facing access to hundreds of AI models through tailnet identity. The article explains that provider integration and secure agent execution were complex enough that Tailscale chose managed routing and sandboxing instead of building those layers in-house.

### Source excerpt

Tailscale on Vercel Hundreds of AI models shipped to customers in-product Model access granted and revoked by tailnet network identity Went from model routing prototype to paying customers in months Tailscale connects a company's laptops, servers, cloud instances, and personal devices into one private network called a tailnet. Remy Guercio, who leads product for Aperture by Tailscale, describes it simply: "It's basically like a VPC that can span any cloud, on-prem, your house, and your phone." Aperture takes that same idea and applies it to AI. Instead of giving every employee, agent, or tool a separate provider API key, Aperture lets companies control model access through the tailnet itself. Add someone to the network, and they can immediately use approved models. Remove them, and access disappears. Under the hood, Aperture is built on Vercel AI Gateway and Vercel Sandbox. AI Gateway gives Tailscale one API for hundreds of models. Sandbox gives agents a safe place to run. Together, they let Tailscale offer model access and agent execution inside a customer's private network, without their team building every piece of AI infrastructure from scratch. Model routing is harder than it looks Tailscale is an infrastructure company, so building the routing and execution layers in-house was the obvious first option. But once they took a deeper look into the engineering effort required, they chose not to. The provider layer looked deceptively simple from the outside. "You would think all of the endpoints are the same," Remy says. "They are not." David Carney, Co-founder and Chief Strategy Officer, has the receipts, because Tailscale still maintains that plumbing for a few customers who haven't migrated to Aperture yet. "There are a lot of things the big providers don't do that blow my mind that the gateway does, like simply putting the cost in the response," he says. "We initially built those systems for customers ourselves, and the complexity is insane." Agents raised the s

## How Uber and Other Companies Are Reducing AI Costs with Open Models and Model Routing

DevFeed: [How Uber and Other Companies Are Reducing AI Costs with Open Models and Model Routing](<https://devfeed.tech/articles/the-pulse-tech-companies-move-to-open-ai-models-40928.md>)

Original publisher: [Read original article](<https://blog.pragmaticengineer.com/the-pulse-tech-companies-move-to-open-ai-models/>)

Author: Ivan Klaric

Published: 2026-09-10T17:22:31Z

Content type: article

Language: en

Sources: [The Pragmatic Engineer](<https://devfeed.tech/sources/the-pragmatic-engineer-2.md>)

Topics: [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [Artificial Intelligence](<https://devfeed.tech/topics/ai.md>), [Inference](<https://devfeed.tech/topics/inference.md>), [LLM evaluation / benchmarking](<https://devfeed.tech/topics/llm-evaluation-benchmarking.md>), [Benchmark](<https://devfeed.tech/topics/benchmark.md>)

Tags: [ai](<https://devfeed.tech/tags/ai.md>), [benchmark](<https://devfeed.tech/tags/benchmark.md>), [benchmarking](<https://devfeed.tech/tags/benchmarking.md>), [cost](<https://devfeed.tech/tags/cost.md>), [inference](<https://devfeed.tech/tags/inference.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [models](<https://devfeed.tech/tags/models.md>), [optimize](<https://devfeed.tech/tags/optimize.md>)

### AI overview

The article reports that companies including Uber, Pinterest, Stripe, Coinbase, Ramp, and AT&T are reducing AI costs by using open models, model routing, benchmarking, and other optimization techniques. It details Uber's use of cheaper inference services, optimized model selection, smaller subagent models, prompt caching, and automatic compaction.

### Source excerpt

Uber, Pinterest, Stripe, Coinbase, Ramp, and AT&T are making large savings on their AI bills by dropping proprietary models and using smart model routing.

## How Smart Model Routing Can Cut LLM Costs by 10X

DevFeed: [How Smart Model Routing Can Cut LLM Costs by 10X](<https://devfeed.tech/articles/how-smart-model-routing-can-cut-llm-costs-by-10x-17990.md>)

Original publisher: [Read original article](<https://blog.bytebytego.com/p/how-smart-model-routing-can-cut-llm>)

Author: ByteByteGo

Published: 2026-09-09T15:30:26Z

Content type: article

Language: en

Sources: [ByteByteGo](<https://devfeed.tech/sources/bytebytego.md>)

Topics: [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [Large Language Model](<https://devfeed.tech/topics/llm.md>), [API](<https://devfeed.tech/topics/api.md>)

Tags: [cost](<https://devfeed.tech/tags/cost.md>), [llm](<https://devfeed.tech/tags/llm.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [models](<https://devfeed.tech/tags/models.md>), [routing](<https://devfeed.tech/tags/routing.md>), [routing-system](<https://devfeed.tech/tags/routing-system.md>), [tokens](<https://devfeed.tech/tags/tokens.md>)

### AI overview

This article explains how smart model routing can reduce LLM application costs by sending simple requests to less expensive models and difficult requests to more capable models. It notes that savings and response quality depend on request types, model price differences, and routing performance, and discusses router, cascading, semantic, and learned routing approaches.

### Source excerpt

Cost reduction isn't a given. It also depends on the types of requests the application receives, the price difference between models, and how well the routing system performs. In this article, we are going to look at various aspects

## Model Routing Is Simple. Until It Isn't.

DevFeed: [Model Routing Is Simple. Until It Isn't.](<https://devfeed.tech/articles/model-routing-is-simple-until-it-isn-t-7268.md>)

Original publisher: [Read original article](<https://huggingface.co/blog/ibm-research/model-routing-is-simple-until-it-isnt>)

Author: Yara Rizk; Eyal Shnarch; Jason Tsay; Merve Unuvar

Published: 2026-07-15T17:27:01Z

Content type: article

Language: en

Sources: [Hugging Face - Blog](<https://devfeed.tech/sources/hugging-face-blog.md>)

Topics: [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [Optimization](<https://devfeed.tech/topics/optimization.md>), [systems](<https://devfeed.tech/topics/systems.md>), [Caching](<https://devfeed.tech/topics/caching.md>), [Claude](<https://devfeed.tech/topics/claude.md>), [anthropic](<https://devfeed.tech/topics/anthropic.md>)

Tags: [agentic](<https://devfeed.tech/tags/agentic.md>), [caching](<https://devfeed.tech/tags/caching.md>), [claude](<https://devfeed.tech/tags/claude.md>), [compliance](<https://devfeed.tech/tags/compliance.md>), [cost](<https://devfeed.tech/tags/cost.md>), [enterprise](<https://devfeed.tech/tags/enterprise.md>), [latency](<https://devfeed.tech/tags/latency.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [optimization](<https://devfeed.tech/tags/optimization.md>), [privacy](<https://devfeed.tech/tags/privacy.md>), [production](<https://devfeed.tech/tags/production.md>), [reasoning](<https://devfeed.tech/tags/reasoning.md>), [systems](<https://devfeed.tech/tags/systems.md>), [tool](<https://devfeed.tech/tags/tool.md>)

### AI overview

Model routing in agentic systems is more than classifying task difficulty or comparing list prices. Effective cost depends on the interaction between the model, workload, and serving infrastructure, including cache-hit rates and cache-read pricing. Production routers must balance cost, quality, latency, specialization, reliability, and enterprise governance constraints such as compliance, data residency, privacy, and approved-model policies.

### Source excerpt

Except it's not. Most routing systems assume that model selection is a classification problem. In our experience building routing into agentic systems, what looks like a model-selection problem quickly becomes a systems optimization problem. Three dimensions made this surprisingly hard for us. We expected GPT-4.1 to be cheaper than Claude Sonnet 4.6. It wasn't.

## The Pulse: a new trend, smart model routing

DevFeed: [The Pulse: a new trend, smart model routing](<https://devfeed.tech/articles/the-pulse-a-new-trend-smart-model-routing-40921.md>)

Original publisher: [Read original article](<https://blog.pragmaticengineer.com/the-pulse-a-new-trend-smart-model-routing/>)

Author: Gergely Orosz

Published: 2026-07-02T18:46:24Z

Content type: article

Language: en

Sources: [The Pragmatic Engineer](<https://devfeed.tech/sources/the-pragmatic-engineer-2.md>)

Topics: [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [AI Models](<https://devfeed.tech/topics/ai-models.md>), [LLMs](<https://devfeed.tech/topics/llms.md>)

Tags: [ai-gateway](<https://devfeed.tech/tags/ai-gateway.md>), [ai-models](<https://devfeed.tech/tags/ai-models.md>), [latency](<https://devfeed.tech/tags/latency.md>), [litellm](<https://devfeed.tech/tags/litellm.md>), [model](<https://devfeed.tech/tags/model.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [openrouter](<https://devfeed.tech/tags/openrouter.md>)

### AI overview

The article surveys emerging smart model-routing tools that select AI models for coding and other tasks based on factors such as prompt difficulty, cost, latency, and availability. It lists offerings including Factory Router, Not Diamond, Vercel AI Gateway, OpenRouter, Kilo Gateway, Requestly.ai, LiteLLM, and others, while noting that some vendors claim cost savings.

### Source excerpt

Are there any 'intelligent' router solutions out there which select the right model for the right task? I looked into it, and there are a few options.

## OpenCode Now Supports DigitalOcean Inference Router for Intelligent Model Routing

DevFeed: [OpenCode Now Supports DigitalOcean Inference Router for Intelligent Model Routing](<https://devfeed.tech/articles/opencode-now-supports-digitalocean-inference-router-for-intelligent-model-routing-19873.md>)

Original publisher: [Read original article](<https://www.digitalocean.com/blog/digitalocean-opencode-inference-routers>)

Author: Musa Malik

Published: 2026-05-28T21:02:42Z

Content type: release

Language: en

Sources: [DigitalOcean](<https://devfeed.tech/sources/digitalocean.md>)

Topics: [Digital Ocean](<https://devfeed.tech/topics/digital-ocean.md>), [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [AI Inference](<https://devfeed.tech/topics/ai-inference.md>), [AI-assisted coding](<https://devfeed.tech/topics/ai-assisted-coding.md>), [Open Source](<https://devfeed.tech/topics/open-source.md>), [coding](<https://devfeed.tech/topics/coding.md>)

Tags: [ai-coding](<https://devfeed.tech/tags/ai-coding.md>), [ai-inference](<https://devfeed.tech/tags/ai-inference.md>), [api](<https://devfeed.tech/tags/api.md>), [cost](<https://devfeed.tech/tags/cost.md>), [digitalocean](<https://devfeed.tech/tags/digitalocean.md>), [latency](<https://devfeed.tech/tags/latency.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [open-source](<https://devfeed.tech/tags/open-source.md>), [product-updates](<https://devfeed.tech/tags/product-updates.md>)

### AI overview

DigitalOcean's Inference Router is in public preview and can be accessed through OpenCode, an open-source AI coding agent. It dynamically routes requests across models to help developers manage latency, cost, and output quality.

### Source excerpt

Coding agents today have a massive spending problem. Every request, whether you're designing system architecture or writing a single-line docstring, often gets routed to the same expensive frontier model. The result: unnecessary token usage, higher inference costs, and little awareness of task complexity or budget constraints. This high cost stems from a "one-size-fits-all" approach to model usage, where premium frontier models are utilized for trivial tasks that don't require such intensive reasoning effort. In multi-agent workflows, where orchestrators delegate work to specialized subagents, this lack of discrimination frequently leads to runaway costs and opaque failure modes. Without intelligent routing, developers can essentially be forced into closed-provider lock-in and high API usage fees, which quickly escalate during exploratory building phases. DigitalOcean Inference Router, now in Public Preview, was built to solve this problem by dynamically routing requests to the right model for the job. As part of DigitalOcean's AI-Native Cloud, it gives developers a unified way to control, optimize, and evaluate AI inference across models. And as of today, you can access it through OpenCode, the open-source AI coding agent, in as little as a few seconds. What is an Inference Router? An Inference Router is the auto-mode pattern engineers are used to, but with deliberate control over the tradeoffs that matter: latency, cost, and output quality. Rather than statically pointing your coding agent to a single model, an Inference Router can analyze each request and route it to the model best suited for that specific task. Not the most powerful model available, but the right model. That distinction is what drives real savings without compromising on your desired quality of output. To use DigitalOcean's Inference Router: Create an Inference Router from the router catalog--pick a preset or build a custom router via the API or UI. No GPU management, no infrastructure to run. Us

## Why AI Infrastructure Matters for Scaling LLM Workloads

DevFeed: [Why AI Infrastructure Matters for Scaling LLM Workloads](<https://devfeed.tech/articles/your-model-doesn-t-matter-your-infrastructure-does-19954.md>)

Original publisher: [Read original article](<https://www.digitalocean.com/blog/your-infrastructure-matters>)

Author: Amit Jotwani

Published: 2026-05-13T16:45:02Z

Content type: article

Language: en

Sources: [DigitalOcean](<https://devfeed.tech/sources/digitalocean.md>)

Topics: [AI Infrastructure](<https://devfeed.tech/topics/ai-infrastructure.md>), [Large Language Model](<https://devfeed.tech/topics/llm.md>), [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [Serverless](<https://devfeed.tech/topics/serverless.md>), [GPU](<https://devfeed.tech/topics/gpu.md>), [API](<https://devfeed.tech/topics/api.md>), [Model Context Protocol (MCP)](<https://devfeed.tech/topics/model-context-protocol-mcp.md>)

Tags: [ai](<https://devfeed.tech/tags/ai.md>), [ai-infrastructure](<https://devfeed.tech/tags/ai-infrastructure.md>), [api](<https://devfeed.tech/tags/api.md>), [digitalocean](<https://devfeed.tech/tags/digitalocean.md>), [engineering](<https://devfeed.tech/tags/engineering.md>), [gpu](<https://devfeed.tech/tags/gpu.md>), [infrastructure](<https://devfeed.tech/tags/infrastructure.md>), [llm](<https://devfeed.tech/tags/llm.md>), [mcp](<https://devfeed.tech/tags/mcp.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [serverless](<https://devfeed.tech/tags/serverless.md>)

### AI overview

This DigitalOcean article argues that infrastructure around an LLM--including routing, data access, observability, and cost control--can matter more than model selection. It describes serverless inference, dedicated GPUs, and routing as stages that can scale on the same platform without re-platforming or rewriting code, and reports an example router reducing costs by about 80% across eight support tickets.

### Source excerpt

Everyone calling an LLM API has access to the same models. So what actually sets technical teams apart? It's everything around the model like the routing logic, the live data pipelines, and the ability to scale from prototype to production without ever rewriting your code. Which LLM tops a benchmark matters less than what becomes possible when infrastructure stops being an afterthought, when one platform owns the full stack from GPU to API. Our Deploy 2026 session walked through this with live demos: serverless inference with web search and MCP tools added in a few lines, a break-even calculator for serverless versus dedicated, and a router built in the console in two minutes that cut costs by ~80% across a batch of eight support tickets. Moving between serverless, dedicated, and routed setups didn't require re-platforming, rewriting code, or switching providers, which is where most inference setups leave money on the table. Watch the full talk below, or keep reading for the rundown. View YouTube video Key takeaways from the Deploy Session: Models are increasingly a commodity. What sets teams apart now is everything around the model: routing, data access, observability, and cost control. Choosing a model is no longer the hard part. The infrastructure you start with should scale with you. The workflow should not force you to re-platform, renegotiate contracts, or rewrite code at every growth milestone. DigitalOcean owns its GPUs, networks, and data centers. As efficiency improves, your cloud bill decreases. As the hardware gets better, your workloads run faster. Your AI journey in three stages Most AI workloads move through three stages. You start small and serverless, you grow into dedicated GPUs when volume justifies it, and somewhere along the way, you want a router making per-request decisions for you. On most platforms, each of those stages means a new product, a new API, and a new contract. On DigitalOcean, there are three configurations of the same platform. T

## Predictive Human Preference: From Model Ranking to Model Routing

DevFeed: [Predictive Human Preference: From Model Ranking to Model Routing](<https://devfeed.tech/articles/predictive-human-preference-from-model-ranking-to-model-routing-31797.md>)

Original publisher: [Read original article](<https://huyenchip.com//2024/02/28/predictive-human-preference.html>)

Author: Chip Huyen

Published: 2024-02-28T00:00:00Z

Content type: article

Language: en

Sources: [Chip Huyen](<https://devfeed.tech/sources/chip-huyen.md>)

Topics: [Model Routing](<https://devfeed.tech/topics/model-routing.md>), [AI Models](<https://devfeed.tech/topics/ai-models.md>), [Model Development](<https://devfeed.tech/topics/model-development.md>), [post-training](<https://devfeed.tech/topics/post-training.md>), [AI Chat](<https://devfeed.tech/topics/ai-chat.md>)

Tags: [ai-models](<https://devfeed.tech/tags/ai-models.md>), [anthropic](<https://devfeed.tech/tags/anthropic.md>), [chatgpt](<https://devfeed.tech/tags/chatgpt.md>), [dpo](<https://devfeed.tech/tags/dpo.md>), [gemini](<https://devfeed.tech/tags/gemini.md>), [latency](<https://devfeed.tech/tags/latency.md>), [model](<https://devfeed.tech/tags/model.md>), [model-routing](<https://devfeed.tech/tags/model-routing.md>), [ranking](<https://devfeed.tech/tags/ranking.md>), [rlhf](<https://devfeed.tech/tags/rlhf.md>)

### AI overview

The article examines predictive human preference: predicting which AI model users will prefer for a specific prompt. It describes model routing as a use case, where prompts could be directed to a preferred model to potentially reduce cost and latency, and discusses using preference predictions to interpret model strengths and weaknesses. It also outlines evaluating predictions against Chatbot Arena and building a preference predictor.

### Source excerpt

A challenge of building AI applications is choosing which model to use. What if we don't have to? What if we can predict the best model for any prompt? Predictive human preference aims to predict which model users might prefer for a specific query. Human preference has emerged to be both the Northstar and a powerful tool for AI model development. Human preference guides post-training techniques including RLHF and DPO. Human preference is also used to rank AI models, as used by LMSYS's Chatbot Arena. Chatbot Arena aims to determine which model is generally preferred. I wanted to see if it's possible to predict which model is preferred for each query. One use case of predictive human preference is model routing. For example, if we know in advance that for a prompt, users will prefer Claude Instant's response over GPT-4, and Claude Instant is cheaper/faster than GPT-4, we can route this prompt to Claude Instant. Model routing has the potential to increase response quality while reducing costs and latency. Another use case of predictive human preference is interpretability. Mapping out a model's performance on different prompts can help us understand this model's strengths and weaknesses. See section Experiment results for examples. Here's what predictive human preference for different model pairs looks like for the prompt "What's the best way to cluster text embeddings?". The predictions were generated by my toy preference predictor. The bright yellow color for the (GPT-4, GPT-3.5-Turbo) cell means that my predictor thinks GPT-4's response is very likely to be preferred to that of GPT-3.5-Turbo's for this prompt. This post first discusses the correctness of Chatbot Arena, which will then be used as a baseline to evaluate the correctness of preference predictions. It then discusses how to build a preference predictor and the initial results. Ranking Models Using Human Preference Using preferential signals (comparisons) to rank models has grown in popularity in the last