# GPT-5 Pro

GPT-5 Pro is a text generation model from OpenAI, available through the Impossibl API. Its published context window is 400,000 tokens. The advertised input rate is $15.00 per million input tokens. The advertised output rate is $120.00 per million output tokens.

- Model identifier: ` openai/gpt-5-pro `
- Creator: OpenAI
- Model type: Text generation
- Canonical model page: [GPT-5 Pro](<https://impossibl.com/openai/gpt-5-pro>)
- API availability: Listed as serving through Impossibl.
- Creator release date: 2025-08-07

## Capabilities and limits

- Context window: 400,000 tokens
- Maximum output tokens: Not published in the public catalog; this is separate from the context window.
- Inputs: text, image
- Outputs: text
- Tool calling: Not published

## API access

Use ` openai/gpt-5-pro ` as the model identifier through the Impossibl API.

Published API endpoints:

- ` /v1/chat/completions `

[API quickstart](<https://impossibl.com/docs/agent-quickstart>) · [Models and billing documentation](<https://impossibl.com/docs/models>)

## Published API prices

All rates are in USD. An unpublished rate is unknown, not zero. Workspace-specific pricing, taxes, balance-purchase fees, billing adjustments, and tool charges can affect the amount paid.

| Usage | Published base rate | Billing unit |
| --- | --- | --- |
| Input | $15.00 | per million input tokens |
| Output | $120.00 | per million output tokens |
| Cache read | Not published | per million cached input tokens |
| Cache write (default retention) | Not published | per million tokens |
| Cache write (one-hour retention) | Not published | per million tokens |
| Audio input | Not published | per million audio input tokens |

## Availability and retirement

The model is listed as serving. No retirement is announced in the current public catalog.

## Frequently asked questions

### What is GPT-5 Pro?

GPT-5 Pro is a text-generation model from OpenAI, available through the Impossibl API.

### How much does GPT-5 Pro cost?

GPT-5 Pro costs $15.00 per million input tokens and $120.00 per million output tokens through the Impossibl API. All rates are in USD.

### What is the context length of GPT-5 Pro?

GPT-5 Pro has a 400,000-token context window through the Impossibl API.

### What inputs and outputs does GPT-5 Pro support?

GPT-5 Pro accepts text and image as input. GPT-5 Pro returns text.

### How do I use GPT-5 Pro through an API?

GPT-5 Pro is available through the Impossibl API. Use openai/gpt-5-pro as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request.

### When was GPT-5 Pro released?

OpenAI released GPT-5 Pro on August 7, 2025.

Sources: [Creator release announcement](<https://openai.com/index/introducing-gpt-5/>)

## Sources and related links

Prices, limits, capabilities, endpoints, and availability come from the public Impossibl catalog. Creator documentation supplies descriptions and release dates where available; it does not override the published API offering.

- [Public Impossibl model catalog](<https://api.impossibl.com/v1/models>)
- [Full model directory as JSON](<https://impossibl.com/models.json>)
- [GPT-5 Pro: model details and pricing](<https://impossibl.com/openai/gpt-5-pro>)
- [Model directory](<https://impossibl.com/models>)