Latest Model Resolution

~author/family-latest slugs always resolve to the newest concrete model in a given family, so you can ship code against a stable alias and pick up new releases without redeploying.

Overview

When a model author ships a new version (for example Anthropic releasing claude-opus-4.7), OpenRouter automatically starts routing ~anthropic/claude-opus-latest to it. Older code calling the alias keeps working — it just runs on the newest version.

This is ideal for:

• Product teams who want to always use the best-in-class model from a specific author without monitoring release notes.
• Internal tools and prototypes where you care about “latest Claude Opus” more than a specific version pinned for reproducibility.
• Rolling migrations where you want to defer version pinning until after a release has stabilised.

Usage

Send a chat completion request with a ~author/family-latest slug as the model:

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import { OpenRouter } from '@openrouter/sdk';
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const openRouter = new OpenRouter({
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  apiKey: '<OPENROUTER_API_KEY>',
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});
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const completion = await openRouter.chat.send({
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  model: '~anthropic/claude-opus-latest',
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  messages: [
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    {
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      role: 'user',
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      content: 'Summarize this in one sentence: ...',
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    },
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  ],
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});
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console.log(completion.choices[0].message.content);
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// The `model` field reflects the concrete version that served the request.
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console.log('Resolved to:', completion.model);

Response

The response’s model field reflects the concrete model that actually served the request, not the alias you sent. This makes it trivial to log or alert on version rollovers:

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{
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  "id": "gen-...",
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  "model": "anthropic/claude-opus-4.7",
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  "choices": [
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    {
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      "message": {
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        "role": "assistant",
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        "content": "..."
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      }
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    }
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  ],
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  "usage": {
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    "prompt_tokens": 12,
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    "completion_tokens": 85,
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    "total_tokens": 97
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  }
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}

How It Works

Each ~author/family-latest slug is mapped to a model family on OpenRouter. When a request comes in:

1. Slug recognition: OpenRouter sees the ~ prefix and identifies which family the alias points to (for example ~anthropic/claude-opus-latest → the Claude Opus family).
2. Target selection: The newest visible model in that family is selected. When a new version ships, it takes over automatically, with no client changes required.
3. Request forwarding: Your request is forwarded to the resolved model and routed across providers exactly as if you’d called that concrete slug directly.
4. Transparent reporting: The response’s model field reports the concrete model that served the request (for example anthropic/claude-opus-4.7), so you can always tell which version answered any given call.

If a family has no eligible model available, the request returns an error rather than silently falling back to something unrelated.

Pricing and Capabilities

~author/family-latest rows on the models page and in /api/v1/models responses report the pricing, context length, modalities, and supported parameters of the target they currently resolve to — not a frozen snapshot. This way:

• Clients that list models for their users see accurate per-token prices.
• Capability-gated flows (for example “only offer this model for vision requests”) see up-to-date modalities.
• Cost dashboards reflect the real rate charged, because requests are billed at the concrete model’s price.

When a new model is promoted to “latest”, these fields update automatically.

Use Cases

• Always-on assistants: Point user-facing agents at ~anthropic/claude-sonnet-latest and get new releases for free.
• Evaluation harnesses: Benchmark “the latest” model per author without editing configs.
• Enterprise pilots: Share a slug with a partner and upgrade them in place when a newer model ships.

Limitations

• Versions can change at any time: When a newer model is rolled in as the latest target, subsequent requests resolve to it. If your application requires a fixed version for reproducibility (for example in regression tests), use the concrete model slug instead.
• Only latest: The router always resolves to the newest eligible model. There is no built-in way to pin to “second newest” or to roll back through the alias — to downgrade, switch to a concrete slug.
• Aliases and hidden models are excluded: The router never resolves to another alias slug or to models that have been hidden.

Pinning to a Specific Version

When you need reproducibility, bypass latest resolution by calling the concrete model slug directly:

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{
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  "model": "anthropic/claude-opus-4.7"
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}

You can see the exact slug your last request resolved to in the response’s model field (see above) or in the activity log for the request.

Related

• Auto Router - Cross-model intelligent selection (paid models)
• Free Models Router - Route to available free models
• Model Variants - :free, :nitro, :thinking, and other suffixes
• API Reference: Chat Completions