GPT 5.3 Chat - Oxen.ai

Try GPT 5.3 Chat in the Workbench

Run this model interactively, tune parameters, and compare outputs.

Model ID: gpt-5-3-chat-latest GPT 5.3 Chat is the GPT-5.3 Instant model used in ChatGPT as the default for chat applications. It features a 128,000-token context window optimized for conversational use, with support for text and image inputs, streaming, function calling, and structured outputs. OpenAI suggests using GPT-5.2 or newer for API deployments.

Metric	Value
Parameter Count	Unknown
Mixture of Experts	Unknown
Context Length	128,000 tokens
Max Output Tokens	16,384 tokens
Multilingual	Yes
Quantized*	Unknown

*Quantization is specific to the inference provider and the model may be offered with different quantization levels by other providers.

Example request

Use the Workbench as a request builder: configure parameters for this model in the UI, then open the API tab to copy the exact cURL or Python call.

Minimal
Basic parameters
All parameters

curl -X POST https://hub.oxen.ai/api/ai/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "gpt-5-3-chat-latest",
  "messages": [
    {
      "role": "user",
      "content": "Hello, what can you do?"
    }
  ]
}'

curl -X POST https://hub.oxen.ai/api/ai/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "gpt-5-3-chat-latest",
  "messages": [
    {
      "role": "user",
      "content": "Hello, what can you do?"
    }
  ],
  "temperature": 0.7,
  "max_tokens": 1024,
  "stream": false
}'

curl -X POST https://hub.oxen.ai/api/ai/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "gpt-5-3-chat-latest",
  "messages": [
    {
      "role": "user",
      "content": "Hello, what can you do?"
    }
  ],
  "temperature": 0.7,
  "max_tokens": 1024,
  "stream": false,
  "top_p": 1.0,
  "frequency_penalty": 0,
  "presence_penalty": 0
}'

Fetch model details

The models endpoint returns the full model object, including its json_request_schema.

curl -H "Authorization: Bearer $OXEN_API_KEY" https://hub.oxen.ai/api/ai/models/gpt-5-3-chat-latest

Request parameters

This model follows the standard OpenAI chat completions request body. See the chat completions reference for the full parameter list.

Inference API

Try GPT 5.3 Chat in the Workbench

​Example request

​Fetch model details

​Request parameters

Example request

Fetch model details

Request parameters