> ## Documentation Index
> Fetch the complete documentation index at: https://docs.openp.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# OpenAI models

> GPT-4o, GPT-5, the o3 series, plus image, audio and Realtime models

OpenPAI fully integrates every available OpenAI model and keeps the model IDs consistent with the official ones.
For **live prices**, refer to [Console → Models](https://openp.ai/dashboard/models).

## Chat models

| Model ID        | Category                   | Context | Input price (per 1M tokens) | Output price (per 1M tokens) | Key features                                                 |
| --------------- | -------------------------- | ------- | --------------------------- | ---------------------------- | ------------------------------------------------------------ |
| `gpt-5.5`       | Latest flagship            | 1M      | See console                 | See console                  | A new class of intelligence for coding and professional work |
| `gpt-5.4`       | Flagship (more affordable) | 1M      | See console                 | See console                  | High-quality code and general chat, better value             |
| `gpt-5.4-mini`  | Economical                 | 400K    | See console                 | See console                  | Strongest mini for code / computer use / subagents           |
| `gpt-5.4-nano`  | Fast & economical          | —       | —                           | —                            | Low-latency, low-cost, high-volume workloads                 |
| `gpt-4o`        | Older flagship multimodal  | 128K    | See console                 | See console                  | Vision, tools, JSON, streaming                               |
| `gpt-4o-mini`   | Older economical           | 128K    | See console                 | See console                  | Still available for legacy projects                          |
| `gpt-3.5-turbo` | Older economical           | 16K     | —                           | —                            | Recommended only for legacy compatibility                    |

<Note>OpenAI's chat capabilities are increasingly centered on the **GPT-5.x series**, and OpenAI recommends the [Responses API](/en/api-reference/openai/responses) for new projects. The GPT-4o series remains callable.</Note>

## Reasoning models (GPT-5.x / o series)

The GPT-5.x series has built-in reasoning, controlled via `reasoning_effort`; the o series (`o3`, `o4-mini`, etc.) is still available.

| Model ID / parameter                   | Reasoning effort | Use case                                           |
| -------------------------------------- | ---------------- | -------------------------------------------------- |
| `gpt-5.5` + `reasoning_effort: low`    | Low              | Simple reasoning, fast responses                   |
| `gpt-5.5` + `reasoning_effort: medium` | Medium           | Balance of quality and speed                       |
| `gpt-5.5` + `reasoning_effort: high`   | High             | Complex logic, math, code                          |
| `o4-mini`                              | Medium-high      | Economical reasoning                               |
| `o3`                                   | High             | Strong reasoning (previous-gen flagship reasoning) |

<Tip>Reasoning models are billed including **invisible reasoning\_tokens** — they aren't shown in `content` but count toward usage. Leave headroom when estimating `max_completion_tokens`.</Tip>

```python theme={null}
resp = client.chat.completions.create(
    model="gpt-5.5",
    messages=[{"role": "user", "content": "Prove that √2 is irrational"}],
    reasoning_effort="high",
    max_completion_tokens=4096,
)
```

## Image generation

| Model ID      | Type             | Notes                                                            |
| ------------- | ---------------- | ---------------------------------------------------------------- |
| `gpt-image-2` | Image generation | Latest generation, highest quality, supports multi-image editing |
| `gpt-image-1` | Image generation | Previous generation, high quality, supports multi-image editing  |
| `dall-e-3`    | Image generation | Classic DALL·E 3, sizes like 1024 / 1792                         |
| `dall-e-2`    | Image generation | Older, cheaper                                                   |

```python theme={null}
img = client.images.generate(
    model="gpt-image-2",
    prompt="A black-and-white pencil sketch of a Shiba Inu wearing glasses",
    size="1024x1024",
    n=1,
)
print(img.data[0].url)
```

## Audio

| Model ID                 | Use case                         |
| ------------------------ | -------------------------------- |
| `whisper-1`              | Speech to text (ASR)             |
| `gpt-4o-transcribe`      | High-quality transcription       |
| `gpt-4o-mini-transcribe` | Economical transcription         |
| `tts-1`                  | Text to speech (standard)        |
| `tts-1-hd`               | Text to speech (hi-fi)           |
| `gpt-4o-mini-tts`        | Next-gen TTS, more natural voice |

```bash theme={null}
curl https://openp.ai/v1/audio/speech \
  -H "Authorization: Bearer $OPENPAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"tts-1","input":"Hello from OpenPAI","voice":"alloy"}' \
  --output speech.mp3
```

## Realtime (voice conversation)

| Model ID                  | Use case                                      |
| ------------------------- | --------------------------------------------- |
| `gpt-realtime-2`          | Latest realtime voice (with reasoning)        |
| `gpt-realtime-1.5`        | High-quality audio in / audio out             |
| `gpt-realtime-translate`  | Realtime speech-to-speech translation         |
| `gpt-realtime-whisper`    | Streaming speech-to-text                      |
| `gpt-4o-realtime-preview` | Previous-gen realtime multimodal conversation |

Endpoint path: `wss://openp.ai/v1/realtime?model=gpt-realtime-2`, over WebSocket.
See the [Realtime API docs](/en/api-reference/openai/realtime).

## Embeddings

| Model ID                 | Dimensions       | Main scenario                   |
| ------------------------ | ---------------- | ------------------------------- |
| `text-embedding-3-small` | 1536 (reducible) | General, default recommendation |
| `text-embedding-3-large` | 3072 (reducible) | High-quality retrieval          |
| `text-embedding-ada-002` | 1536             | Legacy compatibility            |

## Moderations

`omni-moderation-latest` — multimodal content-safety classification, free (some accounts must enable it).

## Responses API

OpenAI's newer `/v1/responses` endpoint unifies conversation state management, suited to agent scenarios.
See the [Responses API](/en/api-reference/openai/responses).

## Detailed fields

* General chat: [Chat Completions](/en/api-reference/openai/chat-completions)
* Image generation: [Images](/en/api-reference/openai/images-generations)
* Audio: [Audio Speech](/en/api-reference/openai/audio-speech), [Audio Transcriptions](/en/api-reference/openai/audio-transcriptions)
* Embeddings: [Embeddings](/en/api-reference/openai/embeddings)