Model Slugs and Naming Conventions on OpenRouter

Q: How do multi-model fallbacks list slugs?

As an ordered array of full model slugs in models (plus a primary model depending on SDK examples).

Q: Can variants appear on router slugs?

Prefer documented combinations only. When unsure, set provider explicitly instead of stacking suffixes.

Q: How should config files store slugs?

As plain strings under logical policy names (planner, fast, cheap), not raw literals at every call site.

OpenRouter model ids are strings, not free-form marketing names.

If you misread the slug grammar, you get 400s, wrong models, or silent quality regressions from the wrong variant.

How to Use This Cheatsheet

Keep this page open while wiring model fields and config maps.
Treat every concrete slug as verify at build against openrouter.ai/models or GET /api/v1/models.
Prefer copying slugs from the catalog UI rather than inventing them from memory.
Log both the requested slug and the response model after fallbacks or auto-routing.

Anatomy of a Slug

[router-or-author]/[model-name][:variant]

Piece	Meaning	Examples (illustrative; verify at build)
Author / org	Catalog owner namespace	`openai`, `anthropic`, `google`, `meta-llama`, `deepseek`, `openrouter`
Model name	Specific model id	`gpt-4o-mini`, `claude-sonnet-4.5`, `gemini-2.5-flash`
Variant suffix	Routing or capability shortcut	`:nitro`, `:floor`, `:free`, `:online`, `:thinking`, `:extended`, `:exacto`
Router slug	Special model that selects others	`openrouter/auto`, free-model routers (see docs)
Latest alias	Moving target for a family	forms like `~openai/gpt-latest` (verify syntax at build)

Full slug examples:

Slug pattern	Reads as
`openai/gpt-4o-mini`	OpenAI GPT-4o mini via OpenRouter catalog
`anthropic/claude-sonnet-4.5`	Anthropic Claude Sonnet release line
`meta-llama/llama-3.3-70b-instruct`	Meta Llama instruct checkpoint
`openrouter/auto`	Auto Router selects a model per prompt
`meta-llama/llama-3.3-70b-instruct:nitro`	Same model, prefer high-throughput providers
`meta-llama/llama-3.3-70b-instruct:floor`	Same model, prefer lowest price providers

Variant Suffix Cheatsheet

Suffix	Intent	Rough equivalent	Notes
`:nitro`	Speed / throughput	`provider.sort = "throughput"`	Good for chat UX
`:floor`	Lowest price	`provider.sort = "price"`	Good for batch
`:free`	Free endpoints when available	free catalog filter	Strict rate limits; verify availability
`:online`	Web-grounded variant	online plugin / search routing	Not every model supports it
`:thinking`	Extended reasoning style	reasoning-enabled routing	Model-dependent
`:extended`	Extended context variant	longer context endpoints	Check actual window
`:exacto`	Quality-first tool-call routing	exacto provider preference	Useful for tool-heavy agents

Suffixes compose only when documented.

Do not invent chains like :nitro:floor unless the catalog shows them.

Provider Slugs vs Model Slugs

These are different namespaces.

Kind	Where used	Example
Model slug	`model` / `models` fields	`anthropic/claude-sonnet-4.5`
Provider slug	`provider.order`, `only`, `ignore`	`anthropic`, `openai`, `azure`, `together`, `deepinfra/turbo`

Base provider slugs often match all regions/variants for that host.

Full endpoint slugs (for example deepinfra/turbo or google-vertex/us-east5) pin a specific endpoint - verify current endpoint names at build.

Common Author Prefixes

Prefix	Typical models	Agent notes
`openai/`	GPT family	Strong tool ecosystem familiarity
`anthropic/`	Claude family	Strong long-context / coding profiles (verify)
`google/`	Gemini family	Multimodal options vary by slug
`meta-llama/`	Llama instruct	Often multi-provider hosted
`deepseek/`	DeepSeek lines	Check tool and reasoning support
`mistralai/`	Mistral lines	Watch context and tool support
`openrouter/`	Routers and meta models	`auto` and related routers

This table is a map of namespaces, not a quality ranking.

Routers and Special Slugs

Slug / feature	Role	When to use
`openrouter/auto`	Per-prompt model selection	Mixed unknown prompts
Free models router	Route among free endpoints	Zero-cost experiments (limits apply)
Latest aliases (`~...` forms)	Track newest family member	Avoid manual renames; accept drift
Presets (product feature)	Named server-side configs	Shared org defaults (verify at build)

Always read response model when using routers or aliases.

JSON Shape Reminder

{
  "model": "anthropic/claude-sonnet-4.5",
  "models": ["openai/gpt-4o-mini", "google/gemini-2.5-flash"],
  "provider": {
    "order": ["anthropic", "amazon-bedrock"],
    "allow_fallbacks": true,
    "ignore": ["deepinfra"]
  }
}

model / models take model slugs.
provider.* lists take provider slugs.
Mixing them up is a frequent 400 source.

Discovery Commands

# List catalog (paginate / filter as needed; verify endpoint at build)
curl -s https://openrouter.ai/api/v1/models \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" | head

import os, httpx
 
r = httpx.get(
    "https://openrouter.ai/api/v1/models",
    headers={"Authorization": f"Bearer {os.environ['OPENROUTER_API_KEY']}"},
    timeout=30.0,
)
r.raise_for_status()
ids = [m["id"] for m in r.json().get("data", [])]
print(len(ids), "models")
print([i for i in ids if i.startswith("anthropic/")][:5])

Mistakes to Avoid

Mistake	Why it hurts
Using UI display names as API ids	Display names are not slugs
Dropping the author prefix	Ambiguous / invalid model
Hardcoding obsolete version numbers forever	Breaks when catalog renames
Assuming `:free` means unlimited	Rate and availability limits apply
Copying a provider slug into `model`	Wrong field namespace
Ignoring response `model` after `:auto`	You do not know what you paid for

FAQs

Where is the source of truth for slugs?

The live OpenRouter models catalog and the models API.

Blog posts and older tutorials go stale.

Are slugs case-sensitive?

Treat them as case-sensitive exact strings.

Copy from the catalog.

Do fine-tunes or private models use the same pattern?

Private/BYO model features use documented scoping rules.

Follow the private models guide for your account type (verify at build).

Is `gpt-4o-mini` without `openai/` ever valid?

Do not rely on bare ids.

Use the full catalog slug OpenRouter lists.

How do multi-model fallbacks list slugs?

As an ordered array of full model slugs in models (plus a primary model depending on SDK examples).

Can variants appear on router slugs?

Prefer documented combinations only.

When unsure, set provider explicitly instead of stacking suffixes.

Why does the response model differ from the request?

Fallbacks, auto-router, or latest-alias resolution selected a different concrete model.

How should config files store slugs?

As plain strings under logical policy names (planner, fast, cheap), not raw literals at every call site.

Do embeddings models share the same author/model form?

Yes, catalog style is similar, but use embeddings endpoints rather than chat completions.

How often do slugs change?

New versions appear frequently.

Pin versions for production agents; use latest aliases only where drift is acceptable.

What about modality suffixes or vision models?

Vision/audio capable models still use author/model slugs; capability is a property of the model card, not always the string shape.

Is OpenRouter's author prefix ever `openrouter/` for normal chat models?

Yes for routers and some meta offerings.

Most third-party models keep their own author prefix.

OpenRouter Setup & Routing Basics - first call with a slug
How Model Routing Actually Works Under an OpenRouter Request - model vs provider layers
Auto-Router: Letting OpenRouter Pick the Best Model for a Prompt - openrouter/auto
Switching Models by Config, Not Code: A Routing Pattern - map logical names to slugs
Troubleshooting Common OpenRouter Setup Errors - invalid model symptoms

Stack versions: Pins from the category manifest (verify at build): OpenRouter (~315+ models, July 2026 pricing/fees); LangGraph 1.0+; CrewAI 1.14+; Microsoft Agent Framework 1.0; Vercel AI SDK 6; Pydantic AI (latest); LlamaIndex (latest); OpenAI Agents SDK (latest + MCP); MCP (Linux Foundation governance); A2A (HTTP+SSE+JSON-RPC 2.0); Solana @solana/web3.js + @solana/spl-token.

If you misread the slug grammar, you get 400s, wrong models, or silent quality regressions from the wrong variant.

How to Use This Cheatsheet

Keep this page open while wiring model fields and config maps.
Treat every concrete slug as verify at build against openrouter.ai/models or GET /api/v1/models.
Prefer copying slugs from the catalog UI rather than inventing them from memory.
Log both the requested slug and the response model after fallbacks or auto-routing.

Anatomy of a Slug

[router-or-author]/[model-name][:variant]

Piece	Meaning	Examples (illustrative; verify at build)
Author / org	Catalog owner namespace	`openai`, `anthropic`, `google`, `meta-llama`, `deepseek`, `openrouter`
Model name	Specific model id	`gpt-4o-mini`, `claude-sonnet-4.5`, `gemini-2.5-flash`
Variant suffix	Routing or capability shortcut	`:nitro`, `:floor`, `:free`, `:online`, `:thinking`, `:extended`, `:exacto`
Router slug	Special model that selects others	`openrouter/auto`, free-model routers (see docs)
Latest alias	Moving target for a family	forms like `~openai/gpt-latest` (verify syntax at build)

Full slug examples:

Slug pattern	Reads as
`openai/gpt-4o-mini`	OpenAI GPT-4o mini via OpenRouter catalog
`anthropic/claude-sonnet-4.5`	Anthropic Claude Sonnet release line
`meta-llama/llama-3.3-70b-instruct`	Meta Llama instruct checkpoint
`openrouter/auto`	Auto Router selects a model per prompt
`meta-llama/llama-3.3-70b-instruct:nitro`	Same model, prefer high-throughput providers
`meta-llama/llama-3.3-70b-instruct:floor`	Same model, prefer lowest price providers

Variant Suffix Cheatsheet

Suffix	Intent	Rough equivalent	Notes
`:nitro`	Speed / throughput	`provider.sort = "throughput"`	Good for chat UX
`:floor`	Lowest price	`provider.sort = "price"`	Good for batch
`:free`	Free endpoints when available	free catalog filter	Strict rate limits; verify availability
`:online`	Web-grounded variant	online plugin / search routing	Not every model supports it
`:thinking`	Extended reasoning style	reasoning-enabled routing	Model-dependent
`:extended`	Extended context variant	longer context endpoints	Check actual window
`:exacto`	Quality-first tool-call routing	exacto provider preference	Useful for tool-heavy agents

Suffixes compose only when documented.

Do not invent chains like :nitro:floor unless the catalog shows them.

Provider Slugs vs Model Slugs

These are different namespaces.

Kind	Where used	Example
Model slug	`model` / `models` fields	`anthropic/claude-sonnet-4.5`
Provider slug	`provider.order`, `only`, `ignore`	`anthropic`, `openai`, `azure`, `together`, `deepinfra/turbo`

Base provider slugs often match all regions/variants for that host.

Full endpoint slugs (for example deepinfra/turbo or google-vertex/us-east5) pin a specific endpoint - verify current endpoint names at build.

Common Author Prefixes

Prefix	Typical models	Agent notes
`openai/`	GPT family	Strong tool ecosystem familiarity
`anthropic/`	Claude family	Strong long-context / coding profiles (verify)
`google/`	Gemini family	Multimodal options vary by slug
`meta-llama/`	Llama instruct	Often multi-provider hosted
`deepseek/`	DeepSeek lines	Check tool and reasoning support
`mistralai/`	Mistral lines	Watch context and tool support
`openrouter/`	Routers and meta models	`auto` and related routers

This table is a map of namespaces, not a quality ranking.

Routers and Special Slugs

Slug / feature	Role	When to use
`openrouter/auto`	Per-prompt model selection	Mixed unknown prompts
Free models router	Route among free endpoints	Zero-cost experiments (limits apply)
Latest aliases (`~...` forms)	Track newest family member	Avoid manual renames; accept drift
Presets (product feature)	Named server-side configs	Shared org defaults (verify at build)

Always read response model when using routers or aliases.

JSON Shape Reminder

{
  "model": "anthropic/claude-sonnet-4.5",
  "models": ["openai/gpt-4o-mini", "google/gemini-2.5-flash"],
  "provider": {
    "order": ["anthropic", "amazon-bedrock"],
    "allow_fallbacks": true,
    "ignore": ["deepinfra"]
  }
}

model / models take model slugs.
provider.* lists take provider slugs.
Mixing them up is a frequent 400 source.

Discovery Commands

# List catalog (paginate / filter as needed; verify endpoint at build)
curl -s https://openrouter.ai/api/v1/models \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" | head

import os, httpx
 
r = httpx.get(
    "https://openrouter.ai/api/v1/models",
    headers={"Authorization": f"Bearer {os.environ['OPENROUTER_API_KEY']}"},
    timeout=30.0,
)
r.raise_for_status()
ids = [m["id"] for m in r.json().get("data", [])]
print(len(ids), "models")
print([i for i in ids if i.startswith("anthropic/")][:5])

Mistakes to Avoid

Mistake	Why it hurts
Using UI display names as API ids	Display names are not slugs
Dropping the author prefix	Ambiguous / invalid model
Hardcoding obsolete version numbers forever	Breaks when catalog renames
Assuming `:free` means unlimited	Rate and availability limits apply
Copying a provider slug into `model`	Wrong field namespace
Ignoring response `model` after `:auto`	You do not know what you paid for

FAQs

Where is the source of truth for slugs?

The live OpenRouter models catalog and the models API.

Blog posts and older tutorials go stale.

Are slugs case-sensitive?

Treat them as case-sensitive exact strings.

Copy from the catalog.

Do fine-tunes or private models use the same pattern?

Private/BYO model features use documented scoping rules.

Follow the private models guide for your account type (verify at build).

Is `gpt-4o-mini` without `openai/` ever valid?

Do not rely on bare ids.

Use the full catalog slug OpenRouter lists.

How do multi-model fallbacks list slugs?

As an ordered array of full model slugs in models (plus a primary model depending on SDK examples).

Can variants appear on router slugs?

Prefer documented combinations only.

When unsure, set provider explicitly instead of stacking suffixes.

Why does the response model differ from the request?

Fallbacks, auto-router, or latest-alias resolution selected a different concrete model.

How should config files store slugs?

As plain strings under logical policy names (planner, fast, cheap), not raw literals at every call site.

Do embeddings models share the same author/model form?

Yes, catalog style is similar, but use embeddings endpoints rather than chat completions.

How often do slugs change?

New versions appear frequently.

Pin versions for production agents; use latest aliases only where drift is acceptable.

What about modality suffixes or vision models?

Vision/audio capable models still use author/model slugs; capability is a property of the model card, not always the string shape.

Is OpenRouter's author prefix ever `openrouter/` for normal chat models?

Yes for routers and some meta offerings.

Most third-party models keep their own author prefix.

OpenRouter Setup & Routing Basics - first call with a slug
How Model Routing Actually Works Under an OpenRouter Request - model vs provider layers
Auto-Router: Letting OpenRouter Pick the Best Model for a Prompt - openrouter/auto
Switching Models by Config, Not Code: A Routing Pattern - map logical names to slugs
Troubleshooting Common OpenRouter Setup Errors - invalid model symptoms

Stack versions: Pins from the category manifest (verify at build): OpenRouter (~315+ models, July 2026 pricing/fees); LangGraph 1.0+; CrewAI 1.14+; Microsoft Agent Framework 1.0; Vercel AI SDK 6; Pydantic AI (latest); LlamaIndex (latest); OpenAI Agents SDK (latest + MCP); MCP (Linux Foundation governance); A2A (HTTP+SSE+JSON-RPC 2.0); Solana @solana/web3.js + @solana/spl-token.

Model Slugs and Naming Conventions on OpenRouter

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Model Slugs and Naming Conventions on OpenRouter