OpenAIFastHigh

GPT-5 Nano

Ultra-fast and lightweight variant of GPT-5. Designed for high-throughput, low-latency applications with a 1M token context window and 32K output tokens at minimal cost.

1 credits

per 1K tokens (avg)

1M token context window

32K max output tokens

Ultra-fast inference

Lowest cost GPT-5 variant

Function calling & JSON mode

Structured outputs

Ideal for high-throughput tasks

Use with AI Assistant

Copy usage instructions for Claude, ChatGPT, or other AI

llms.txt

Model Specifications

Context Window

1.0M

tokens

Max Output

33K

tokens

Training Cutoff

2025-03

Compatible SDK

OpenAI

Capabilities

Vision

Function Calling

Streaming

JSON Mode

System Prompt

Token Pricing (per 1M tokens)

Token Type	Credits	USD Equivalent
Input Tokens	100	$0.10
Output Tokens	800	$0.80
Cached Tokens	25	$0.03

* 1 credit ≈ $0.001 (actual charges may vary based on usage)

Quick Start

curl -X POST "https://api.core.today/llm/openai/v1/chat/completions" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer cdt_your_api_key" \
  -d '{
  "model": "gpt-5-nano",
  "messages": [
    {
      "role": "system",
      "content": "Classify the following customer message into one of these categories: billing, technical, general, feedback. Respond with only the category name."
    },
    {
      "role": "user",
      "content": "I was charged twice for my subscription last month and need a refund."
    }
  ],
  "max_completion_tokens": 50
}'

Parameters

Parameter	Type	Required	Default	Description
`messages`	array	Yes	-	Array of message objects with role and content
`model`	string	Yes	gpt-5-nano	Model identifier
`max_completion_tokens`	integer	No	4096	Maximum tokens in response (up to 32768). Note: use max_completion_tokens, not max_tokens
`reasoning_effort`	string	No	medium	Reasoning effort level: low, medium, or high
`stream`	boolean	No	false	Enable Server-Sent Events streaming
`response_format`	object	No	-	Format of response: { type: 'json_object' } for JSON mode
`tools`	array	No	-	List of tools (functions) the model can call

Examples

Quick Classification

High-speed text classification with GPT-5 Nano

curl -X POST "https://api.core.today/llm/openai/v1/chat/completions" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer cdt_your_api_key" \
  -d '{
  "model": "gpt-5-nano",
  "messages": [
    {
      "role": "system",
      "content": "Classify the following customer message into one of these categories: billing, technical, general, feedback. Respond with only the category name."
    },
    {
      "role": "user",
      "content": "I was charged twice for my subscription last month and need a refund."
    }
  ],
  "max_completion_tokens": 50
}'

Data Extraction

Fast structured data extraction

curl -X POST "https://api.core.today/llm/openai/v1/chat/completions" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer cdt_your_api_key" \
  -d '{
  "model": "gpt-5-nano",
  "messages": [
    {
      "role": "system",
      "content": "Extract key information from the text and return as JSON."
    },
    {
      "role": "user",
      "content": "Meeting scheduled with John Smith from Acme Corp on March 15, 2026 at 2:00 PM in Conference Room B to discuss Q1 budget review."
    }
  ],
  "response_format": {
    "type": "json_object"
  },
  "max_completion_tokens": 500
}'