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

# OpenAI (GPT)

> GPT-5, GPT-4o, GPT-4.1, o3, o4-mini, and the full OpenAI model lineup in ZeroTwo.

OpenAI's models are among the most widely used in the world. ZeroTwo provides access to the full lineup — from the flagship GPT-5 and multimodal GPT-4o to the powerful o-series reasoning models.

## Available models

| Model            | Context | Strengths                                                             | Premium? |
| ---------------- | ------- | --------------------------------------------------------------------- | -------- |
| **GPT-5**        | Large   | Most capable OpenAI model; leading benchmark scores, broad capability | Yes      |
| **GPT-4.1**      | 128k    | Excellent coding and instruction-following                            | Yes      |
| **GPT-4.1-mini** | 128k    | Faster, more efficient version of 4.1                                 | Pro+     |
| **GPT-4.1-nano** | 128k    | Ultra-fast, cost-efficient; standard tier                             | Standard |
| **GPT-4o**       | 128k    | Multimodal (vision), fast, strong all-around                          | Yes      |
| **GPT-4o-mini**  | 128k    | Fast and efficient standard model                                     | Standard |
| **GPT-5-mini**   | —       | Fast standard model; good general-purpose default                     | Standard |
| **o3**           | —       | Advanced reasoning; top-tier for math and logic                       | Premium  |
| **o4-mini**      | —       | Efficient reasoning; strong balance of speed and depth                | Premium  |

## GPT model strengths

### Coding and instruction-following

OpenAI's GPT models are consistently strong at generating, debugging, and explaining code. GPT-4.1 in particular is optimized for coding tasks and excels at following precise multi-step instructions.

### Multimodal capabilities (GPT-4o)

GPT-4o accepts both text and images as input. Send screenshots, diagrams, charts, or photos alongside your text prompt and GPT-4o will analyze the visual content and respond. This is useful for:

* Debugging from a screenshot of an error
* Analyzing charts or data visualizations
* Describing or understanding image content
* OCR and reading text from images

### Broad general knowledge

GPT models are trained on extensive datasets and perform well across a wide range of domains — science, history, business, writing, and more.

## Reasoning models: o3 and o4-mini

OpenAI's o-series models are specialized for extended reasoning. They think through problems step by step before responding, producing significantly better results on:

* Complex mathematical problems and proofs
* Multi-step logical reasoning
* Challenging coding problems — algorithm design, optimization, debugging
* Research analysis and synthesis
* Any task where working through the problem carefully produces a better answer

| Model       | Speed  | Capability                       | Best for                                               |
| ----------- | ------ | -------------------------------- | ------------------------------------------------------ |
| **o3**      | Slower | Highest reasoning capability     | The hardest problems where accuracy is paramount       |
| **o4-mini** | Faster | Strong reasoning, more efficient | Most reasoning tasks — good balance of depth and speed |

<Info>
  Reasoning models (o3, o4-mini) are slower than standard GPT models — they take longer because they do more work before responding. Use them when you need the extra accuracy, not as a general-purpose default.
</Info>

## Choosing the right OpenAI model

| Use case                        | Recommended model         |
| ------------------------------- | ------------------------- |
| General chat and Q\&A           | GPT-4o-mini or GPT-5-mini |
| Complex coding and development  | GPT-4.1 or GPT-5          |
| Analyzing images or screenshots | GPT-4o                    |
| Math, logic, hard reasoning     | o3 or o4-mini             |
| Fast iterations and drafts      | GPT-4o-mini or GPT-5-mini |
| Highest-quality output          | GPT-5                     |

<Tip>
  GPT-4o is a strong default for most tasks involving text and images. For pure-text complex work, GPT-4.1 or GPT-5 are excellent options. Use o3 or o4-mini specifically for reasoning-heavy tasks.
</Tip>

## Standard tier OpenAI models

The following OpenAI models are in ZeroTwo's standard tier — no monthly cap, available on all plans including Free:

* **GPT-5-mini**: Fast, capable standard model. Good general-purpose default on Free or when conserving premium quota.
* **GPT-4o-mini**: Efficient, fast, and capable for routine tasks. 128k context.
* **GPT-4.1-nano**: Ultra-fast and cost-efficient for high-frequency simple tasks.

## Best use cases

<CardGroup cols={2}>
  <Card title="Software development" icon="cpu">
    GPT-4.1 is a top choice for full-stack development, API design, code review, debugging, and technical documentation.
  </Card>

  <Card title="Multimodal analysis" icon="image">
    GPT-4o's vision capability makes it ideal for screenshot analysis, diagram interpretation, and visual content understanding.
  </Card>

  <Card title="Complex reasoning" icon="brain">
    o3 and o4-mini are OpenAI's best models for math, logic, and problems that benefit from careful step-by-step thinking.
  </Card>

  <Card title="General content creation" icon="sparkles">
    GPT-5 and GPT-4o are strong choices for writing, research, analysis, and general-purpose tasks at high quality.
  </Card>
</CardGroup>

## Related

<CardGroup cols={2}>
  <Card title="Reasoning models" icon="brain" href="/models/reasoning-models">
    Full guide to o3, o4-mini, and how reasoning models work in ZeroTwo.
  </Card>

  <Card title="Anthropic (Claude)" icon="sparkles" href="/models/providers/anthropic">
    Compare with Claude Sonnet 4.6 and Opus 4.6 for writing and long context.
  </Card>

  <Card title="Premium vs. Standard" icon="star" href="/models/premium-vs-standard">
    Understand which OpenAI models count against your monthly quota.
  </Card>

  <Card title="Model picker" icon="sliders" href="/models/model-picker">
    How to find and select OpenAI models in ZeroTwo.
  </Card>
</CardGroup>