Last refreshed 2026-05-11. Next refresh: weekly.
Why use GPT-5.1 on OpenRouter?
OpenRouter offers GPT-5.1 with pay-as-you-go pricing at $1.25/1M input tokens. OpenRouter is a multi-provider LLM aggregator offering unified API access to 300+ models from all major labs and emerging providers, with automatic failover for reliability.
Setup recipe
Docs fallbackUse the provider REST API or SDKCreate a provider API keymodel: openai/gpt-5.1openai/gpt-5.1Request example
openai/gpt-5.1.Gotchas
- Use provider model ID "openai/gpt-5.1", not the LLMReference slug "gpt-5.1".
Pricing
| Type | Price (per 1M) |
|---|---|
| Input tokens | $1.25 |
| Output tokens | $10.00 |
Capabilities
About GPT-5.1
OpenAI's GPT-5.1 is the main thinking model in the GPT-5.1 family, released November 13, 2025 via API (ChatGPT rollout began November 12, 2025). Features adaptive reasoning that dynamically adjusts thinking time by task complexity, with a reasoning_effort parameter supporting none/low/medium/high settings. Deprecated in ChatGPT as of March 11, 2026 in favor of newer models.
FAQ
What does GPT-5.1 cost on OpenRouter?
On OpenRouter, GPT-5.1 costs $1.25 per 1M input tokens and $10 per 1M output tokens.
What is the context window for GPT-5.1 on OpenRouter?
GPT-5.1 supports a 400k token context window on OpenRouter.
What API model ID do I use for GPT-5.1 on OpenRouter?
Use the model ID openai/gpt-5.1 when calling OpenRouter's API.
Who created GPT-5.1?
GPT-5.1 was created by OpenAI as part of the GPT-5.1 model family.
Is GPT-5.1 open source?
GPT-5.1 is not open source; the seed data lists it as proprietary.