GPT-5.1-Codex
OpenAI · released Nov 13, 2025
- Type
- Closed
- Input
- None held
- Output
- None held
- Cached
- None held
We don't hold a list price for this model yet · hosted only — we have no record of published weights
Our take
Written Sep 30, 2026GPT-5.1-Codex is a hosted coding model: we list no download for it, so using it means choosing a host. It has been measured, and its strongest showing is resolving real GitHub issues when an agent harness drives it.
Reach for it when the job is fixing issues in an existing codebase and the work can be handed to an agent harness, or when long files and multi-file context would otherwise have to be split up before the question. Both listed hosts charge the same rate, so the choice between them is not a price decision. Skip it if you need to run the model on your own machine, since we list no download for it.
The case for it
- Resolves 66% of real GitHub issues end-to-end on SWE-bench Verified, measured inside the mini-SWE-agent harness — a result for the model in that harness, not for the model on its own.
- 400,000 tokens of request capacity, so long documents need not be split up first, though reliable recall across all of it is unverified in our data.
- Text and image input with written output, so a screenshot or diagram does not have to be described in words first.
The case against it
- 79th of 95 on Arena Code (WebDev) as of 25 Sep 2026 — a board that records which web-app result people preferred, not whether the code was correct.
- We list no download for it, so using it means choosing a host, and both listed hosts charge the same rate.
- The parameter count is not published, so you cannot size it against a machine of your own.
How good is it?
EverydayGeneral questions and everyday reasoning
Not yet scored on Arena Text (overall).
CodingWriting and fixing code on its own
Not yet scored on Arena Coding. It is on Arena Code (WebDev), in 79th of 95 with 1337.
AgenticPlanning, calling tools, staying on task
Not yet scored on Arena Agent. It is on SWE-bench Verified, in 15th of 42 with 66.
WritingDrafting and rewriting prose
Not yet scored on Arena Creative Writing.
Every published score for this model2 scoresEvery figure we hold, from 2 boards, with who ran it and a link to the source — including the boards no rating above is built on.
Where to rent it
Prices checked 2 hours ago — each listing carries its own date.
- per 1M tokens
- $1.25 in / $10.00 out
- Context served
- 400K
- Throughput
- ~59 tok/s
| Provider | In / out per 1M tokens | Context | Throughput | Trains on prompts | Logs prompts | Zero retention |
|---|---|---|---|---|---|---|
| OpenRouterOpenRouter's own listing | $1.25 / $10.00checked 2 hours ago | 400K | not measured | Unknown | Unknown | Unknown |
| Microsoft Azure AIThrough OpenRouter | $1.25 / $10.00checked 2 hours ago | 400K128K max reply | 59 tok/s | No | No | Confirmed |
OpenRouterAcross the 2 listings we hold: 1 says it does not train on prompts, 0 say they do and 1 does not say. 1 appears in the zero-retention registry we check; the rest are unknown to us.
What each host's API supports
From the parameter list each endpoint publishes. Streaming is omitted: nothing we hold reports it, for any model.
| Provider | Tool calling | JSON output | Strict schema |
|---|---|---|---|
| OpenRouterOpenRouter's own listing | ✓ | ✓ | ✓ |
| Microsoft Azure AIThrough OpenRouter | ✓ | ✓ | ✓ |
Tool calling: 2 of 2 listings say yes. JSON output: 2 of 2 listings say yes. Strict schema: 2 of 2 listings say yes.
Models people weigh against GPT-5.1-Codex
When we formed this view
Recent changes
What moved
first indexed by our pipelineEach date is the day we first saw the change, or the day the maker announced it.
What we do not know about this model yet
- Nothing we hold says whether an endpoint streams, so we do not show it either way.
- 1 of 2 listings does not say whether it trains on prompts.
- We don't hold a list price for this model yet — the gap is ours, not the lab's.
- We hold no batch or off-peak rate for any of its listings.
Licence and identifiers
What the licence allowsWe hold no licence record for this model. Inside are the identifiers you need to pull it — its Hugging Face repo where we have one, our slug and a machine-readable card.
Licence
We hold no licence record for this model, and no record of published weights either — so we can neither summarise its terms nor point you at the weights.
Identifiers
- Takes in, gives back
- Text and images in, text out
- Catalogue slug
- openai-gpt-5-1-codex