Blog — OpenRouter Blog

LLM API Rate Limits: How to Fix OpenAI and Claude 429 Errors

A 429 Too Many Requests error means you sent more requests or tokens than your limit allows in the current time window. OpenAI, Anthropic and OpenRouter all return it, and it usually shows up the first time an app runs under real load or a batch job fans out across several workers.

November 11, 2026

LLM Quantization: What fp8 and fp4 Do to Quality and Price

When you call an open-weight model through an API, several providers may serve it at different precisions, such as 16-bit bf16, 8-bit fp8 or 4-bit fp4. The precision can affect both the answers and the price. LLM quantization creates these versions by storing a model's weights in fewer bits, so the model needs less memory and hardware, at some cost in accuracy.

November 11, 2026

MCP vs CLI vs Skills: What Each Costs in Context

Every tool you give an agent sends its definition to the model on every request, and you pay for it as input tokens. A Model Context Protocol (MCP) server can add tens of thousands of tokens to the context window. The usual alternatives are a command-line tool (CLI) or a skill.

November 11, 2026

Best OCR Model for Scanned Documents, Measured

We made eight scanned pages from text we wrote, ran them through 15 vision models, Mistral OCR and Tesseract, and checked every value. Claude Opus 5.5 was the most accurate and Mistral OCR the best value.

November 10, 2026

How to Build a Voice AI Agent

A voice agent needs to do more than generate a good answer. It must understand what someone said, decide what to do, call any needed tools, and start speaking again before the pause gets awkward.

November 10, 2026

How to Get Structured Output from Any LLM: JSON Schema, Tool Calls, or a Decision Model

When your code reads fields from a model's reply, like an order ID or a refund amount, it expects clean JSON every time. Most of the time, it gets it. But now and then the model wraps the JSON in a code fence, adds a field you didn't ask for, or sends a number as text, and your code breaks. If you use several models, one fix won't cover them all, because each model and provider handles structured output in its own way.

November 10, 2026

Introducing the New Auto and Auto Code Routers

The next generation of Auto Router, rebuilt on a new technical foundation, plus Auto Code, a new router specialized for coding work. Both weigh eleven factors per request against live pricing, provider health, benchmarks, and cache state to pick a model and reasoning effort from the model pool your governance policies allow.

November 6, 2026

Build an AI Code Reviewer with OpenRouter

Code reviewers that only read a Git diff have to guess whether a change breaks anything, and their fixes come back as prose you apply by hand. This guide builds a Python reviewer on the OpenRouter Responses API that uploads your changed files into a Linux sandbox, runs checks to confirm each bug, and returns validated patches. A review takes one to four minutes and costs $0.015 to $0.045.

November 1, 2026

How to Build Your Own Always-On AI Agent

An always-on AI agent wakes up on a schedule, checks something with tools, and reports or acts without you asking. This tutorial builds one in TypeScript with the OpenRouter Agent SDK that watches Hacker News, remembers what it has seen across restarts, stops any run at five cents, and waits for your approval before it posts.

October 31, 2026

Open-Weight vs Closed-Weight Models: What's the Difference?

An open-weight model publishes its trained weights, so anyone can run, fine-tune or serve it. A closed-weight model is only available from its maker. We used a year of OpenRouter usage data, our price catalog and benchmark scores to show what that difference changes for cost, providers and quality.

October 31, 2026

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LLM API Rate Limits: How to Fix OpenAI and Claude 429 Errors

OpenRouter is Joining Stripe

Ori Eval: Find the Best Model for What You're Building

Surpassing Frontier Performance with Fusion

LLM Quantization: What fp8 and fp4 Do to Quality and Price

MCP vs CLI vs Skills: What Each Costs in Context

Best OCR Model for Scanned Documents, Measured

How to Build a Voice AI Agent

How to Get Structured Output from Any LLM: JSON Schema, Tool Calls, or a Decision Model

Introducing the New Auto and Auto Code Routers

Build an AI Code Reviewer with OpenRouter

How to Build Your Own Always-On AI Agent

Open-Weight vs Closed-Weight Models: What's the Difference?