o3 Mini API: OpenAI's chat / LLM model, one key away
o3 Mini via the ApexApi gateway
The small o3, for reasoning-shaped work that has to run at volume. Cheaper per call than most frontier chat models. Call it through ApexApi's unified, OpenAI-compatible API with one `ak-` key, alongside every other model in the catalog. It supports a 200,000-token context window, tool / function calling, image (vision) input, and streaming responses. Pricing is $1.32 input and $5.28 output per 1M tokens, billed pay-per-use from your credit balance with no subscription.
o3 Mini is served through ApexApi's unified, OpenAI-compatible API. One key, one format, with smart routing and automatic failover. Provider: OpenAI.
Why o3 Mini
200,000-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
- 200K tokens
- Max output
- 100K tokens
- Streaming
- Yes
- Tool / function calling
- Yes
- Vision input
- Yes
o3 Mini: measured reliability
From real calls ApexApi made to o3 Mini during health sweeps over the last 30 days. Our own measurements, not vendor claims.
- Success rate
- 100%
- Avg latency
- 3.8s
- Calls measured
- 1
- Last checked
- Aug 30
See how o3 Mini compares against every model we serve on the model rankings.
o3 Mini pricing
- A million tokens in and a million out costs $6.60 here, all-in.
- It runs 13.6× cheaper than GPT-4, the pricier option from the same maker.
Getting started with o3 Mini
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/o3-mini",
messages=[{"role": "user", "content": "Hello!"}],
)
print(response.choices[0].message.content)o3 Mini use cases
What teams build with o3 Mini 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.
o3 Mini 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.
o3 Mini vs Claude Opus 4.7
Compare o3 Mini 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 →o3 Mini vs GPT-5.5
Compare o3 Mini against this model on price, capabilities, and latency. A/B them with a single key on ApexApi.
Learn more about GPT-5.5 API →o3 Mini vs Gemini 3.1 Pro Preview
Compare o3 Mini 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 →o3 Mini API: FAQ
How do I call o3 Mini 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/o3-mini`. The API is OpenAI-compatible, so an existing OpenAI SDK works once you change the base URL and key.
How much does o3 Mini cost on ApexApi?
$1.32 per million input tokens and $5.28 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 o3 Mini?
200,000 tokens. It can return up to 100,000 tokens in a single response.
Does o3 Mini support tool calling and image input?
o3 Mini supports tool / function calling, image (vision) input, and streaming responses.
What should I use instead of o3 Mini?
From the same maker, GPT-5 Mini costs less for lighter work and GPT-4.1 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 o3 Mini?
One API key. Every major AI model. Pay only for what you use.
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