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Providers

Using OpenRouter

Reach hundreds of models from every major vendor through one OpenRouter API key, with gateway spend that matches your OpenRouter invoice.

OpenRouter is a marketplace rather than a single vendor: one key reaches models from OpenAI, Anthropic, Google, Meta, DeepSeek, Qwen, xAI and many more, and OpenRouter chooses an upstream host for each request. Adding it as a provider serves those models to your apps through the Universal API, on your OpenRouter account and your OpenRouter billing.

Three things set this provider apart, and each one changes something you'll type:

• Model references carry the vendor prefix, so they have two slashes.
• Claude models serve the Messages API, not the Responses API.
• Reported spend matches your OpenRouter invoice, because OpenRouter prices each request and the gateway bills from that figure.

Model references include the vendor prefix

Every OpenRouter model ID is vendor-qualified — anthropic/claude-sonnet-5, openai/gpt-6-sol, meta-llama/llama-3.3-70b-instruct. A gateway model reference prefixes your provider name onto that, so it has two slashes:

Code
openrouter/anthropic/claude-sonnet-5
openrouter/openai/gpt-6-sol
openrouter/meta-llama/llama-3.3-70b-instruct

The first segment is your provider name, and everything after the first slash is the model ID exactly as OpenRouter publishes it. This is the same shape Vertex AI uses.

Supported endpoints

Which endpoints a model serves depends on what kind of model it is. Claude is served on a different API from every other chat model, and embedding models serve only embeddings:

Endpoint	Claude models (anthropic/…)	Other chat models	Embedding models
/v1/chat/completions	✅ (translated)	✅	❌
/v1/messages	✅	❌	❌
/v1/messages/count_tokens	❌	❌	❌
/v1/responses	❌	✅	❌
/v1/embeddings	❌	❌	✅

Before you begin

You need an OpenRouter API key. Create one at openrouter.ai/keys; it starts with sk-or-v1-.

You also need credit on the OpenRouter account the key belongs to, or requests come back with OpenRouter's own insufficient-credit error.

Add the provider

Adding or editing providers requires the Edit permission, granted to Zuplo account and project Admins—see Managing Providers.

Routing shortcuts

OpenRouter lets you append a routing preference to any model ID:

Suffix	Effect
:nitro	Prefer the fastest upstream host
:floor	Prefer the cheapest upstream host
:online	Add web search to the request
:exacto	Prefer hosts that call tools most accurately

These work through the gateway and are forwarded to OpenRouter unchanged. They don't appear in the model picker, because they aren't separate models — the gateway resolves openrouter/openai/gpt-6-sol:nitro against the openai/gpt-6-sol catalog entry and sends the suffix upstream.

Two consequences worth knowing:

• A model-filtering allow list matches literally. Allowing openrouter/openai/gpt-6-sol does not allow openrouter/openai/gpt-6-sol:nitro. Add the suffixed reference explicitly if you want it.
• Other suffixes aren't supported. OpenRouter's :free variants are separate models, and the gateway's OpenRouter catalog doesn't include them, so a request for one is rejected like any model outside your selections.

Call the models

Point any OpenAI-compatible client at your app URL with /v1 appended:

Code
import OpenAI from "openai";

const client = new OpenAI({
  baseURL:
    "https://my-gateway-main-2e18f50.zuplo.app/config_fe0a04972d2848e0a94ae4b8bcd1497e/v1",
  apiKey: process.env.ZUPLO_APP_API_KEY,
});

const completion = await client.chat.completions.create({
  model: "openrouter/openai/gpt-6-sol",
  messages: [{ role: "user", content: "Hello!" }],
});

Provider routing preferences

OpenRouter's provider option is forwarded, so you can express upstream preferences per request:

Code
const completion = await client.chat.completions.create({
  model: "openrouter/openai/gpt-6-sol",
  messages: [{ role: "user", content: "Hello!" }],
  // @ts-expect-error -- an OpenRouter extension, not part of the OpenAI types
  provider: { sort: "throughput" },
});

provider is forwarded on embeddings and the Responses API too. On chat completions, transforms, reasoning and plugins are forwarded the same way. The Responses API forwards plugins, and reasoning is a standard Responses parameter.

Call Claude models on the Messages API

Claude models on OpenRouter serve Anthropic's native Messages API, so the Anthropic SDK works against them directly. Set baseURL without /v1 — the Anthropic SDK appends that itself — and pass your key as authToken:

Code
import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({
  baseURL:
    "https://my-gateway-main-2e18f50.zuplo.app/config_fe0a04972d2848e0a94ae4b8bcd1497e",
  authToken: process.env.ZUPLO_APP_API_KEY,
});

const message = await client.messages.create({
  model: "openrouter/anthropic/claude-sonnet-5",
  max_tokens: 1024,
  messages: [{ role: "user", content: "Hello!" }],
});

authToken, not apiKey: the SDK's apiKey sends an x-api-key header, which the gateway doesn't read.

For the Vercel AI SDK, see the OpenRouter section of the AI SDK guide.

Costs

OpenRouter prices every request itself and reports the figure in the response, and the gateway records that figure rather than computing one from a stored rate card. Your reported spend therefore reconciles with your OpenRouter invoice.

This matters more here than for a single-vendor provider. A :floor request and a :nitro request for the same model can run on different upstream hosts at different prices, so there is no single per-model rate that would be correct for both.

Responses carry an X-Cost-USD header alongside X-Cost-Source: provider, which tells you the figure came from OpenRouter rather than from a rate card.

Troubleshooting

400 saying /v1/responses is not supported — you sent a Claude model to /v1/responses. Use /v1/messages, or /v1/chat/completions, which the gateway translates onto the Messages API; see the table above.

400 naming /v1/messages — you sent a model other than Claude to /v1/messages, which serves only Claude models here.

An error saying the model is not included in your model selections — the model isn't selected on this provider. Open the provider on the AI Providers page and enable it.

400 rejecting models, route or fallbacks — see the caution above; use a route backup model instead.

400 from /v1/messages/count_tokens — OpenRouter doesn't offer token counting.

404 from OpenRouter — usually a model ID typo. The ID after your provider name must match OpenRouter's exactly, vendor prefix and all.

A key that won't save — OpenRouter keys start with sk-or-v1- and contain no whitespace. Re-copy it from openrouter.ai/keys.

Next steps

• Universal API — the endpoints every provider shares
• Managing providers — editing models and keys
• AI Providers — the full provider and capability matrix