GPT-5.3 Chat
Access GPT-5.3 Chat through one API key. Reliable previous-generation OpenAI model.
OpenAI's previous generation chat model. Solid reasoning and generation at a competitive price.
No credit card required. Takes 30 seconds.
2,400+
Developers
1.2M+
API calls served
100+
Endpoints
$0.01
Per call
Yep, that's it.
Try it live
Send a message and see GPT-5.3 Chat respond in real time.
Maximum tokens in the response.
Real-time tokens
Context Window
128K tokens
Max Output
16K tokens
Input Price
$2.45 / 1M tokens
Output Price
$19.60 / 1M tokens
Strengths
GPT-5.3 Chat is OpenAI's prior-generation chat model, offering flagship-class quality at a lower price than the current line.
As a mature release, it has well-understood behavior and consistent outputs for production conversational workloads.
Handles multi-step reasoning and explanation well across general knowledge and technical topics.
A 128,000-token context window comfortably holds long conversations and supporting documents in a single request.
Quick start
Copy this snippet and start making calls with GPT-5.3 Chat.
const res = await fetch('https://api.yepapi.com/v1/ai/chat', {
method: 'POST',
headers: {
'x-api-key': 'YOUR_API_KEY',
'Content-Type': 'application/json',
},
body: JSON.stringify({
"model": "openai/gpt-5.3-chat",
"messages": [
{
"role": "user",
"content": "Explain API gateways in 2 sentences."
}
],
"maxTokens": 256
}),
});
const { data } = await res.json();
console.log(data.message.content);Why use GPT-5.3 Chat through YepAPI?
GPT-5.3 Chat API: a reliable previous-generation OpenAI model
GPT-5.3 Chat is OpenAI's previous-generation chat model, delivering solid reasoning and generation at a competitive price. With a 128K-token context window and pricing of $2.45 per 1M input tokens and $19.60 per 1M output tokens, it is a dependable choice for conversational apps that do not need the very latest model.
Through YepAPI you call GPT-5.3 Chat with one OpenAI-compatible API key. That same key also reaches other models and YepAPI's SEO, SERP, and web-scraping endpoints, so you can build assistants that answer questions and pull live data together.
What is GPT-5.3 Chat?
GPT-5.3 Chat is OpenAI's previous-generation chat-oriented model, built for reliable conversation, reasoning, and general text generation. As a mature, well-tested release, it offers predictable behavior that production teams value, with solid performance across explanation, drafting, and Q&A. It carries a 128,000-token context window and up to 16,384 output tokens per response, enough for long multi-turn dialogues plus reference material. Positioned below the current flagship, it costs $2.45 per 1M input and $19.60 per 1M output tokens, making it a practical option when proven reliability matters more than having the newest model.
Build with GPT-5.3 Chat via YepAPI
Send requests to the OpenAI-compatible /v1/ai/chat endpoint with your YepAPI key. Since it follows the standard Chat Completions schema, existing OpenAI SDKs work after changing only the base URL and model name. Use it for customer-support bots, in-app assistants, and conversational features that need consistency over novelty. One key also covers other models plus SEO, SERP, and scraping APIs, so your assistant can answer naturally and fetch fresh web data from a single integration.
GPT-5.3 Chat API pricing — $2.45 / $19.60 per 1M tokens
GPT-5.3 Chat costs $2.45 per 1M input tokens and $19.60 per 1M output tokens. As a previous-generation model, it offers flagship-style chat quality below the newest pricing tier, which suits steady conversational workloads. Billing is per token, so short support replies cost little and you only pay for the dialogue you actually generate.
GPT-5.3 Chat for conversational assistants
The model is a strong fit for conversational products where reliability and cost predictability matter: support chatbots, help-desk assistants, and embedded chat features. Its 128K context keeps long threads and knowledge-base snippets in view, and its proven behavior reduces surprises in production. When you want dependable dialogue without paying for the latest generation, GPT-5.3 Chat is a sensible default.
Try GPT-5.3 Chat free
Every new YepAPI account includes $5 in free credit with no card required. That is enough to wire GPT-5.3 Chat into a prototype assistant and test its conversational quality on your own use case before committing.
Start generating in 30 seconds
$5 free credit on signup. No credit card required. Pay per call.
What developers say
“Switched from SerpAPI and cut our SERP costs by 80%. Same data quality, way simpler billing.”
“One API key for AI models, SERP data, and web scraping. Saved us from managing 4 separate providers.”
“The $5 free credit let us prototype our entire rank tracking feature before committing. No other API does that.”
Frequently asked questions
OpenAI's previous generation chat model. Solid reasoning and generation at a competitive price.
Input tokens cost $2.45 per 1M tokens and output tokens cost $19.60 per 1M tokens through YepAPI. No monthly minimums — you only pay for what you use.
Sign up for a free API key, then send requests to the /v1/ai/chat endpoint.
GPT-5.3 Chat supports a 128K token context window with up to 16K output tokens per request.
Ready to use GPT-5.3 Chat?
$5 free credit on signup. No credit card required. Pay per call.
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