OpenAI: GPT-5.3-Codex API
About
Build advanced reasoning agents with OpenAI: GPT-5.3-Codex, a specialized AI model optimized for complex logic and chain-of-thought tasks. This model delivers cost-effective pricing at $1.75/1M input and $14.00/1M output tokens, native tool calling support. Access OpenAI: GPT-5.3-Codex via the Kilo Gateway API with up to 128K output tokens.
Capabilities
Input Modalities
imagetext
Output Modalities
text
Reasoning
Yes
Structured Output
Limits
Context Window
400K
Tokens
Input Limit
400K
Tokens
Max Output
128K
Tokens
Pricing
Standard (per 1M tokens)
Input
$1.75
Output
$14.00
Frequently Asked Questions
OpenAI: GPT-5.3-Codex by Kilo Gateway costs $1.75 per 1M input tokens and $14.00 per 1M output tokens.
Model Details
API Integration
NPM Package
@ai-sdk/openai-compatible
Environment Variables
KILO_API_KEY
API Base URL
https://api.kilo.ai/api/gateway