Last refreshed 2026-05-20. Next refresh: weekly.
Why use GPT-5.3 Chat on OpenAI API?
OpenAI API offers GPT-5.3 Chat with pay-as-you-go pricing at $1.75/1M input tokens. OpenAI is a leading AI research and deployment company dedicated to developing safe and beneficial artificial general intelligence (AGI) for humanity.
Setup recipe
Python + curlpip install openaiexport OPENAI_API_KEY=...import os
from openai import OpenAI
client = OpenAI() # reads OPENAI_API_KEY from env
response = client.chat.completions.create(gpt-5.3-chat-latestRequest example
import os
from openai import OpenAI
client = OpenAI() # reads OPENAI_API_KEY from env
response = client.chat.completions.create(
model="gpt-5.3-chat-latest",
messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)Gotchas
- Use provider model ID "gpt-5.3-chat-latest", not the LLMReference slug "gpt-5.3-chat".
- Use the model slug directly, e.g. "gpt-4o" or "gpt-4.1-mini".
- The examples expect OPENAI_API_KEY; rename it only if your application config maps the new variable.
Pricing
| Type | Price (per 1M) |
|---|---|
| Input tokens | $1.75 |
| Output tokens | $14.00 |
Capabilities
About GPT-5.3 Chat
GPT-5.3's conversational model, marketed as GPT-5.3 Instant. Available via the OpenAI API as gpt-5.3-chat-latest and in Azure AI Foundry as gpt-5.3-chat preview. Released March 3, 2026 as an update to ChatGPT's default model with reduced hallucinations, anti-sycophancy alignment, and faster short-prompt responses. GPT-5.5 Instant succeeded it as ChatGPT's default model on May 5, 2026.
FAQ
What does GPT-5.3 Chat cost on OpenAI API?
On OpenAI API, GPT-5.3 Chat costs $1.75 per 1M input tokens and $14.00 per 1M output tokens.
What is the context window for GPT-5.3 Chat on OpenAI API?
GPT-5.3 Chat supports a 128,000 token context window on OpenAI API.
What API model ID do I use for GPT-5.3 Chat on OpenAI API?
Use the model ID gpt-5.3-chat-latest when calling OpenAI API's API.
Who created GPT-5.3 Chat?
GPT-5.3 Chat was created by OpenAI as part of the GPT-5.3 model family.
Is GPT-5.3 Chat open source?
GPT-5.3 Chat is not open source; the seed data lists it as proprietary.