How should you compare gpt-5.1-codex-mini with a larger coding model?

Compare code correctness, latency, and completion quality on the routine development tasks you intend to route to a smaller model.

How should you set the output budget for gpt-5.1-codex-mini?

For gpt-5.1-codex-mini, set the max_tokens or max_completion_tokens parameter to control spending per call. Start with a budget aligned to your typical response length and increase only when longer outputs are genuinely needed. Monitor token usage in the API response headers to tune your budget over time.

What model ID should you use for gpt-5.1-codex-mini?

Use the exact model ID gpt-5.1-codex-mini . Validate the same request and evaluation path used by your current integration.

Can you call gpt-5.1-codex-mini with the SDK you already use?

Yes. gpt-5.1-codex-mini is compatible with the standard SDK. Set the model parameter to gpt-5.1-codex-mini and use your MixRoute API key. If your current code already calls the compatible API, changing the base URL and model ID is typically all that is needed.

How should you begin a pilot with gpt-5.1-codex-mini?

Use gpt-5.1-codex-mini for bounded development work while retaining tests and review for every proposed code change.

How does gpt-5.1-codex-mini compare with other models, and what should you compare?

Compare gpt-5.1-codex-mini against models of similar capability and pricing on your actual workload. Evaluate latency, output quality, instruction following, and cost per task. Run side-by-side tests with your own prompts — the best model depends on your specific use case, not just benchmark scores.

When was gpt-5.1-codex-mini released, and is it still maintained?

GPT-5.1-Codex Mini was released on 2025-11-13. Its catalog status is stable. Check the model page for deprecation notices before you build a long-lived integration on it.

GPT-5.1-Codex Mini API: Pricing & Specs

Model specs

Model ID: gpt-5.1-codex-mini

Context length: 400K
Max output: 128K
I/O modalities
Released: 2025-11

API endpoints

One MixRoute gateway, OpenAI-compatible

OpenAI-compatible /v1/chat/completions POST

Pricing

Flat rate, unit: /1M Tokens

Input

$1.2500 /1M Tokens

Completion

$10.0000 /1M Tokens

Selection summary

Quickly judge whether it fits your workload

What is this model good for?

Codex model for coding and agentic tasks

GPT-5.1-Codex Mini: GPT-5.1-Codex Mini is a smaller, more cost-effective, less-capable version of GPT-5.1-Codex.. 400,000-token context.

What should you check before using it?

400,000 context, 128,000 output

OpenAI model. Supports tool calling, structured outputs, function calling. Knowledge cutoff: 2024-09-30.

Why use it through MixRoute?

Drop-in via OpenAI-compatible endpoint on MixRoute

Set the model parameter to "gpt-5.1-codex-mini" and use your MixRoute API key.

Capabilities & compatibility

Unconfirmed capabilities stay "Unknown," no guesses

Tool calling

GPT-5.1-Codex Mini supports function and tool calls.

EX Send a tools definition; the response returns tool_calls to execute and feed results back.

Structured output

GPT-5.1-Codex Mini can produce JSON-formatted output on demand.

EX response_format: { type: "json_schema" } forces valid JSON output.

Streaming

GPT-5.1-Codex Mini supports streamed responses.

EX stream: true streams tokens incrementally, so chat UIs render as they arrive.

Prompt caching

GPT-5.1-Codex Mini supports prompt caching under supported routing conditions.

EX Keep the system prompt and tool definitions at the start of the request; repeated prefixes are automatically billed at the cache-read rate.

Vision input

GPT-5.1-Codex Mini can process image inputs alongside text.

EX Pass a base64-encoded image in a image_url content part alongside text messages.

OpenAI SDK

Call GPT-5.1-Codex Mini through MixRoute's OpenAI-compatible endpoint.

EX Change base_url to https://api.mixroute.ai/v1; everything else follows the OpenAI style.

Token cost estimator

Live estimate from this page's pricing, not an actual bill

Input tokens Max per request 400K

Output tokens Max per request 128K

Requests / month

Cache hit rate –

This model has no cache-read price; caching is not counted

FAQ

gpt-5.1-codex-mini is a smaller and faster option for scoped coding work where a lighter Codex-oriented model is sufficient.

Get started

01

Create an API key

Generate a key in the Console; one key calls every model.
02

Set the base URL

Fully OpenAI SDK-compatible; just swap the URL to connect.

https://api.mixroute.ai/v1
03

Specify the model ID

In the request's model field, enter:

gpt-5.1-codex-mini

Create an API key

New users get $5 in free credits

Test this model and alternate routes with the same request format

Start from a real workload, then let quality, total cost, and failure conditions decide whether to send production traffic.

Create an API key View integration docs