GPT-4o API: OpenAI's chat / LLM model, one key away
GPT-4o via the ApexApi gateway
A pinned GPT-4o snapshot. Use it when you need output that cannot shift as OpenAI updates the rolling alias; otherwise call gpt-4o. Call it through ApexApi's unified, OpenAI-compatible API with one `ak-` key, alongside every other model in the catalog. It supports a 128,000-token context window, tool / function calling, image (vision) input, and streaming responses. Pricing is $3.00 input and $12.00 output per 1M tokens, billed pay-per-use from your credit balance with no subscription.
GPT-4o is served through ApexApi's unified, OpenAI-compatible API. One key, one format, with smart routing and automatic failover. Provider: OpenAI.
Why GPT-4o
128,000-token context
Reason over long documents, codebases, and multi-turn history in a single request.
Tool & function calling
Structured outputs and tool orchestration for agentic and automation workloads.
Vision input
Send images alongside text for document, UI, and visual-understanding tasks.
Specifications
- Modality
- chat
- Context window
- 128K tokens
- Max output
- 16.4K tokens
- Streaming
- Yes
- Tool / function calling
- Yes
- Vision input
- Yes
GPT-4o: measured reliability
From real calls ApexApi made to GPT-4o during health sweeps over the last 30 days. Our own measurements, not vendor claims.
- Success rate
- 100%
- Avg latency
- 3.2s
- Calls measured
- 1
- Last checked
- Aug 30
See how GPT-4o compares against every model we serve on the model rankings.
GPT-4o pricing
- A million tokens in and a million out costs $15.00 here, all-in.
- It runs 6× cheaper than GPT-4, the pricier option from the same maker.
Getting started with GPT-4o
OpenAI-compatible. Point your client at ApexApi, swap your key, and call it. No new SDK to learn.
from openai import OpenAI
client = OpenAI(
base_url="https://api.apexapi.dev/v1",
api_key="<YOUR_APEXAPI_KEY>",
)
response = client.chat.completions.create(
model="openai/gpt-4o-2024-11-20",
messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)GPT-4o use cases
What teams build with GPT-4o on ApexApi.
Agents & automation
Tool-using agents that orchestrate multi-step workflows and call APIs.
Coding assistants
Code generation, refactoring, reviews, and multi-file reasoning.
RAG & knowledge apps
Summarization and long-document Q&A grounded in your own data.
GPT-4o vs other models
How it compares, and on ApexApi you can switch between any of them with a single string change, same key, same endpoint.
GPT-4o vs Claude Opus 4.7
Compare GPT-4o against this model on price, capabilities, and latency. A/B them with a single key on ApexApi.
Learn more about Claude Opus 4.7 API →GPT-4o vs GPT-5.5
Compare GPT-4o against this model on price, capabilities, and latency. A/B them with a single key on ApexApi.
Learn more about GPT-5.5 API →GPT-4o vs Gemini 3.1 Pro Preview
Compare GPT-4o against this model on price, capabilities, and latency. A/B them with a single key on ApexApi.
Learn more about Gemini 3.1 Pro Preview API →GPT-4o API: FAQ
How do I call GPT-4o through ApexApi?
Create an ApexApi key, point your client at https://api.apexapi.dev/v1, and POST to /v1/chat/completions with the model set to `openai/gpt-4o-2024-11-20`. The API is OpenAI-compatible, so an existing OpenAI SDK works once you change the base URL and key.
How much does GPT-4o cost on ApexApi?
$3.00 per million input tokens and $12.00 per million output tokens, all-in with no separate platform fee. You buy credits and pay per call, with no subscription or minimum.
What is the context window for GPT-4o?
128,000 tokens. It can return up to 16,384 tokens in a single response.
Does GPT-4o support tool calling and image input?
GPT-4o supports tool / function calling, image (vision) input, and streaming responses.
What should I use instead of GPT-4o?
From the same maker, GPT-5.6 Luna costs less for lighter work and GPT-5.6 Terra is the step up when this one falls short. Switching is one string: both run on the same endpoint and the same key, so there is nothing to re-integrate.
Ready to build with GPT-4o?
One API key. Every major AI model. Pay only for what you use.
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