GPT-5.4
Access GPT-5.4 through one API key. OpenAI's latest and most capable model.
OpenAI's latest flagship model. Significant improvements in reasoning, coding, and instruction-following with a 1M token context window.
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-5.4 respond in real time.
Maximum tokens in the response.
Real-time tokens
Context Window
1.1M tokens
Max Output
33K tokens
Input Price
$3.50 / 1M tokens
Output Price
$21.00 / 1M tokens
Strengths
GPT-5.4 is a recent OpenAI flagship with significant gains in reasoning, coding, and instruction-following over prior generations.
Processes up to 1,050,000 tokens per request, enough for entire codebases, large document sets, or long agent histories.
Strong multi-step reasoning across general and technical domains, suited to analysis, planning, and complex problem solving.
Generates and refactors code reliably across languages, returning up to 32,768 output tokens per response.
Quick start
Copy this snippet and start making calls with GPT-5.4.
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-5.4",
"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-5.4 through YepAPI?
GPT-5.4 API — pricing, context window & access
GPT-5.4 is an OpenAI flagship model with significant improvements in reasoning, coding, and instruction-following, paired with a 1,050,000-token context window. It returns up to 32,768 output tokens per response.
With YepAPI you reach GPT-5.4 through one OpenAI-compatible key — the same key that also covers GPT-5.5, GPT-5.4 Mini and Nano, Claude, Gemini, and the SEO, SERP and scraping APIs.
What is GPT-5.4?
GPT-5.4 is an OpenAI flagship in the GPT-5 series, bringing significant improvements in reasoning, coding, and instruction-following over earlier generations. It anchors a tiered family that includes the cheaper GPT-5.4 Mini and Nano below it and the newer GPT-5.5 above it. With a 1,050,000-token context window and up to 32,768 output tokens, it handles large codebases and document sets in a single request. It's the balanced flagship choice when you want strong, current OpenAI intelligence without stepping up to the very latest or most expensive tier.
Build with GPT-5.4 via YepAPI
YepAPI serves GPT-5.4 on the OpenAI-compatible /v1/ai/chat endpoint. Set your base URL, add your key, and use the model string gpt-5.4 — the chat-completions format carries over unchanged. Moving up to GPT-5.5 or down to GPT-5.4 Mini and Nano for cheaper work is a one-string change, as is switching to Claude or Gemini. The same key also reaches search and scraping endpoints, so flagship apps and data pipelines run on one account.
GPT-5.4 API pricing — $3.50 / 1M input, $21.00 / 1M output
GPT-5.4 costs $3.50 per 1M input tokens and $21.00 per 1M output tokens through YepAPI. That sits below the newest GPT-5.5 flagship while still offering frontier-class reasoning and a 1M-token window, making it a sensible default for serious work that doesn't need the very latest model. The large context can run up input volume on full-corpus jobs, so size prompts deliberately. You pay only for tokens used.
GPT-5.4 for reasoning & code generation
GPT-5.4 is a strong general flagship for analysis and engineering. Its superior reasoning handles planning, multi-step problem solving, and technical analysis, while advanced code generation and 32K output tokens let it produce substantial implementations or refactors in one pass. The 1M-token window means it can hold an entire codebase or document set in context, so it's well-suited to coding assistants and analytical agents that need both depth and a large working memory.
Try GPT-5.4 free
Every new YepAPI account includes $5 in free credit, no card required. That's enough to test GPT-5.4's reasoning and coding on your own tasks before committing. Create an account, copy your key, and start calling GPT-5.4 right away.
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 latest flagship model. Significant improvements in reasoning, coding, and instruction-following with a 1M token context window.
Input tokens cost $3.50 per 1M tokens and output tokens cost $21.00 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-5.4 supports a 1.1M token context window with up to 33K output tokens per request.
Ready to use GPT-5.4?
$5 free credit on signup. No credit card required. Pay per call.
Explore more models
GPT-4o Mini
OpenAIAccess GPT-4o Mini through one API key. Fast, cheap, and OpenAI-compatible.
GPT-4o
OpenAIAccess GPT-4o through one API key. Flagship reasoning and multimodal capabilities.
GPT-5.5
OpenAIAccess GPT-5.5 through one API key. OpenAI's newest and most capable model.