---
title: GPT-5 — LLM | ModelsLab
description: Access GPT-5 API for 400k context, freeform tools, and agentic reasoning. Generate complex responses via LLM endpoint.
url: https://modelslab.com/gpt-5
canonical: https://modelslab.com/gpt-5
type: website
component: Seo/ModelPage
generated_at: 2026-04-24T23:14:34.042774Z
---

Available now on ModelsLab · Language Model

GPT-5
GPT-5 API Power
---

[Try GPT-5](/models/openai/gpt-5) [API Documentation](https://docs.modelslab.com)

![GPT-5](https://assets.modelslab.ai/generations/a05bf5f0-fe1a-4815-b135-3325beef2516.webp)

Unlock GPT-5 Capabilities
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Massive Context

### 400k Token Window

Process entire documents in one call with 272k input and 128k output tokens.

Agentic Workflows

### Responses API Chains

Maintain chain-of-thought across turns for multi-step reasoning and tool use.

Freeform Tools

### Execute Arbitrary Code

Send raw text like SQL or commands directly to custom tools without JSON limits.

Examples

See what GPT-5 can create
---

Copy any prompt below and try it yourself in the [playground](/models/openai/gpt-5).

Code Debug

“Analyze this Python function for bugs, explain fixes step-by-step, and output corrected code in a fenced block.”

Data Query

“Generate SQL for sales data from 2025, filter top products by region, using dialect-specific syntax.”

Agent Task

“Plan multi-step workflow to research market trends, call web search tool, synthesize findings into report.”

JSON Schema

“Output user profile data matching this JSON schema: {name: string, age: number, skills: array}, constrained format.”

For Developers

A few lines of code.
GPT-5. One call.
---

ModelsLab handles the infrastructure: fast inference, auto-scaling, and a developer-friendly API. No GPU management needed.

- **Serverless:** scales to zero, scales to millions
- **Pay per token,** no minimums
- **Python and JavaScript SDKs,** plus REST API

[API Documentation ](https://docs.modelslab.com)

PythonJavaScriptcURL

Copy

```
<code>import requests

response = requests.post(
    "https://modelslab.com/api/v7/llm/chat/completions",
    json={
  "key": "YOUR_API_KEY",
  "prompt": "",
  "model_id": ""
}
)
print(response.json())</code>
```

FAQ

Common questions about GPT-5
---

[Read the docs ](https://docs.modelslab.com)

### What is GPT-5 context limit?

GPT-5 supports 400,000 tokens total, with ~272k input and 128k output. This exceeds GPT-4's 32k limit.

### How does GPT-5 API differ from gpt3 5?

GPT-5 adds Responses API for agentic chains, freeform inputs, and CFGs. Earlier models lack persistent reasoning.

### What endpoints support GPT-5 LLM?

Use /v1/chat/completions for chats, /v1/responses for agents, /v1/realtime for streaming. All enable streaming.

### Is GPT-5 a gpt 5 alternative?

GPT-5 serves as gpt 5 alternative with superior reasoning, tool use, and 400k context. Access via our LLM endpoint.

### Does openai gpt3 5 match GPT-5 llm?

No, GPT-5 llm offers freeform function calling and built-in computer use. gtp3 5 lacks these agentic features.

### Can GPT-5 handle gpt 5 alternative tasks?

Yes, it excels in coding, multi-step agents, and structured outputs as a gpt 5 alternative. Use grammar constraints for precision.

Ready to create?
---

Start generating with GPT-5 on ModelsLab.

[Try GPT-5](/models/openai/gpt-5) [API Documentation](https://docs.modelslab.com)

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*This markdown version is optimized for AI agents and LLMs.*

**Links:**
- [Website](https://modelslab.com)
- [API Documentation](https://docs.modelslab.com)
- [Blog](https://modelslab.com/blog)

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*Generated by ModelsLab - 2026-04-25*