OpenRouter

Available for: Python and TypeScript.

OpenRouter provides a unified API for 200+ models. Wrap your OpenRouter client with wrapOpenRouter() (TypeScript) to trace every call, regardless of which underlying model is used — or patch the openai module with patch_openrouter() (Python), since OpenRouter uses an OpenAI-compatible API.

Installation

npm install @zespan/sdk openai

pip install zespan openai

OpenRouter uses an OpenAI-compatible API — install the openai package as the client in both languages.

Setup

import OpenAI from "openai";
import { zespan } from "@zespan/sdk";

zespan.init({ apiKey: process.env.ZESPAN_API_KEY! });

const openrouter = zespan.wrapOpenRouter(
  new OpenAI({
    baseURL: "https://openrouter.ai/api/v1",
    apiKey: process.env.OPENROUTER_API_KEY!,
  })
);

import os
import zespan

zespan.init(api_key=os.environ["ZESPAN_API_KEY"])
zespan.patch_openrouter()

import openai  # import after patching
client = openai.OpenAI(
    base_url="https://openrouter.ai/api/v1",
    api_key=os.environ["OPENROUTER_API_KEY"],
)

In Python, patch_openrouter() is an alias for patch_openai() — it monkey-patches the openai module’s chat completions method globally rather than wrapping a single client instance. This means: (1) any openai.OpenAI() client in your process is traced after calling it, whether it points at OpenRouter’s base_url or not; (2) traced events are tagged provider: "openai", not provider: "openrouter"; and (3) cost is calculated from token counts and generic pricing, not from OpenRouter’s own reported cost. The TypeScript wrapOpenRouter() wraps only the client instance you pass it, tags events provider: "openrouter", and prefers OpenRouter’s actual reported cost (see below). There is currently no separate Python codepath that gives OpenRouter-specific cost or provider tagging — patch_openrouter() and patch_openai() are the same function.

Example

const response = await openrouter.chat.completions.create({
  model: "anthropic/claude-sonnet-4-6",
  messages: [{ role: "user", content: "What model are you?" }],
});

response = client.chat.completions.create(
    model="anthropic/claude-sonnet-4-6",
    messages=[{"role": "user", "content": "What model are you?"}],
)

What gets captured

Field	Details	TypeScript	Python
Model	The OpenRouter model identifier (e.g. `anthropic/claude-sonnet-4-6`)	Yes	Yes
Input tokens	From the `usage` response field	Yes	Yes
Output tokens	From the `usage` response field	Yes	Yes
Cost	OpenRouter’s reported cost (`usage.cost` or the `x-ratelimit-cost` header), falling back to token-based calculation	Yes	No — always token-based, since `patch_openrouter()` reuses the generic OpenAI cost path
Provider tag on events	The event’s `provider` field	`openrouter`	`openai`
Latency	Total request duration	Yes	Yes

Cost reporting accuracy in TypeScript depends on whether OpenRouter returns cost data in the response. For most popular models it does. For custom or fine-tuned routes, token-based calculation is used as a fallback.

Overview

TypeScript SDK

Python SDK

Advanced SDK Configuration

Integrations

LLM Providers

Agent Frameworks

RAG Frameworks

Vector Databases

Custom / Other

Guides

Installation

Setup

Example

What gets captured

​Installation

​Setup

​Example

​What gets captured

Installation

Setup

Example

What gets captured