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OpenAI

GPT-5.3

OpenAI's latest flagship — frontier reasoning with 256K context, native tool orchestration, and multimodal mastery.

Released

Context Window

256.0K

tokens
Max Output

32.8K

tokens
Input / 1M

$5.00

per 1M tokens
Output / 1M

$15.00

per 1M tokens

Capabilities

Vision
Function Calling
Streaming
JSON Mode
System Prompt
Tool Use

Pricing Comparison

Quick Start

curl
curl -X POST https://api.nemorouter.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer sk-your-api-key" \
  -d '{
    "model": "openai/gpt-5.3",
    "messages": [
      {"role": "system", "content": "You are a helpful assistant."},
      {"role": "user", "content": "Hello!"}
    ],
    "max_tokens": 256
  }'

Replace sk-your-api-key with your NemoRouter API key. Use openai/gpt-5.3 as the model identifier.

Start building today

One API key.
Every model. Zero fee.

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No credit card required · OpenAI-compatible API

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Platform Fee

locked in for life

99.9%

Uptime SLA

enterprise-grade reliability