Back to Models
OpenAI
GPT-5.3
OpenAI's latest flagship — frontier reasoning with 256K context, native tool orchestration, and multimodal mastery.
Released
Context Window
256.0K
tokensMax Output
32.8K
tokensInput / 1M
$5.00
per 1M tokensOutput / 1M
$15.00
per 1M tokensCapabilities
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.
Join the first 100K founding customers and lock in 0% platform fee forever. All enterprise features included.
No credit card required · OpenAI-compatible API
22+
AI Models
from leading providers
76+
Providers
OpenAI, Anthropic, Google...
0%
Platform Fee
locked in for life
99.9%
Uptime SLA
enterprise-grade reliability