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

# GPT-5.3 Codex API

> GPT-5.3 Codex API on Venice: 400K context, $1.75 input and $14.00 output per 1M tokens. Anonymized access without your identity.

> [accordion] Plain-text specification
>
> ## GPT-5.3 Codex API
>
> GPT-5.3 Codex is a large language model by OpenAI, available on the Venice API as `openai-gpt-53-codex`. Requests are anonymized, so the provider never sees your identity.
>
> GPT-5.3 Codex, the successor to GPT-5.2 Codex, is OpenAI's specialized coding model, optimized for advanced software development, code generation, and technical problem-solving. It supports a longer context window and longer outputs than GPT-5.2 Codex.
>
> ### GPT-5.3 Codex API pricing
>
> | Model ID | Variant | Privacy | Price |
> | - | - | - | - |
> | `openai-gpt-53-codex` | Standard | Anonymized | $1.75 / $14.00 per 1M |
>
> ### GPT-5.3 Codex specifications
>
> | Spec | Value |
> | - | - |
> | Provider | OpenAI |
> | Released | Feb 24, 2026 |
> | Privacy | Anonymized |
> | Status | Stable |
> | Context window | 400K tokens |
> | Max output | 128K tokens |
> | Reasoning effort | none, low, medium, high, xhigh |
>
> ### How to use the GPT-5.3 Codex API
>
> Send requests to `POST https://api.venice.ai/api/v1/responses` with `"model": "openai-gpt-53-codex"` and your API key.
>
> ```bash theme={"system"}
> curl https://api.venice.ai/api/v1/responses \
>   -H "Authorization: Bearer $VENICE_API_KEY" \
>   -H "Content-Type: application/json" \
>   -d '{
>     "model": "openai-gpt-53-codex",
>     "input": "Explain TEE attestation in two sentences.",
>     "reasoning": { "effort": "high" }
>   }'
> ```
>
> ### Related models
>
> * [Gemini 3.1 Pro Preview API](https://docs.venice.ai/models/gemini-3-1-pro-preview.md): $2.50 / $15.00 per 1M
> * [Aion 3.0 API](https://docs.venice.ai/models/aion-3-0.md): $3.75 / $7.50 per 1M
> * [Claude Sonnet 4.6 API](https://docs.venice.ai/models/claude-sonnet-4-6.md): $3.00 / $15.00 per 1M
> * [Qwen 3.7 Max API](https://docs.venice.ai/models/qwen-3-7-max.md): $2.70 / $8.05 per 1M


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