o3 API
Advanced reasoning model that thinks step-by-step for complex math, science, and coding problems.
💰 Save up to 70% vs official OpenAI pricingTechnical Specifications
| Provider | OpenAI |
| Model Family | o3 |
| Release Date | 2026-05 |
| Context Window | 200K |
| Max Output Tokens | 100,000 |
| Input Price | $2.00 / 1M tokens |
| Output Price | $8.00 / 1M tokens |
| Vision Support | No |
| Function Calling | No |
| JSON Mode | No |
| Streaming | No |
| Fine Tuning | Not Available |
| Status | Active ✓ |
Overview
o3 is OpenAI's current reasoning-class AI model, released in 2026-05. Advanced reasoning model that thinks step-by-step for complex math, science, and coding problems.
With a 200K context window and maximum output of 100,000 tokens, o3 is well-suited for chain-of-thought and complex reasoning. At $2.00/1M input and $8.00/1M output, it offers balanced pricing within the OpenAI ecosystem.
o3 supports 3 capabilities: Reasoning, Coding, Math. Fine-tuning is not available for this model. The model serves as an chain-of-thought solution for developers building text-based AI applications.
Through AI API Hub, you can access o3 with USDT & USDC payments, no credit card required. All via a fully OpenAI-compatible API — just change your base URL and start building in 30 seconds.
API Examples
Python
from openai import OpenAI
client = OpenAI(
api_key="YOUR_API_KEY",
base_url="https://api.apiyihe.org/v1"
)
response = client.chat.completions.create(
model="o3",
messages=[
{"role": "user", "content": "Hello"}
]
)
print(response.choices[0].message.content)JavaScript / Node.js
import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.API_KEY,
baseURL: "https://api.apiyihe.org/v1"
});
const response = await client.chat.completions.create({
model: "o3",
messages: [
{ role: "user", content: "Hello" }
]
});
console.log(response.choices[0].message.content);cURL
curl https://api.apiyihe.org/v1/chat/completions \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_API_KEY" \
-d '{
"model": "o3",
"messages": [
{"role": "user", "content": "Hello"}
]
}'Compare Alternatives
Frequently Asked Questions
What is o3?
o3 is OpenAI's current reasoning model. Advanced reasoning model that thinks step-by-step for complex math, science, and coding problems.. It features a 200K context window, supports Reasoning, Coding, Math, and is available through AI API Hub with USDT/USDC payments.
How much does o3 cost?
o3 pricing: $2.00 per 1M input tokens, $8.00 per 1M output tokens. Pay-as-you-go with no minimum commitment. Sign up at AI API Hub and start with as little as $5.
o3 vs Claude Opus 4.8?
o3: $2.00/$1M input, 200K context. Claude Opus 4.8: $5.00/$1M input, 1M context. o3 is more cost-effective. Chain-of-thought. Compare them at /compare/o3-vs-claude-opus-4.8/.
o3 context window?
o3 has a 200K context window, capable of processing up to 200,000 tokens in a single request. Maximum output tokens: 100,000.
Does o3 support function calling?
No, o3 does not natively support function calling. For function calling use cases, consider OpenAI's flagship models.
Is o3 multimodal?
No, o3 is a text-only model. For multimodal use cases, consider models with vision/audio capabilities.
o3 API rate limits?
o3 rate limits: 10K RPM. Higher tier plans offer increased throughput. For high-volume production use, consider OpenAI's faster variant models.
How to access o3 API?
Access o3 through AI API Hub: (1) Register at api.apiyihe.org/register?aff=8JZC, (2) Deposit USDT/USDC, (3) Get your API key instantly, (4) Use the OpenAI-compatible endpoint https://api.apiyihe.org/v1 with model name "o3". Start building in under 30 seconds.