GPT-4o Mini

OpenAI
Text & Chat

Small, fast, and affordable model for lightweight tasks. Great balance of speed and capability.

Try GPT-4o Mini now
Send a single prompt and stream a response inline. Hit Cmd+Enter to submit.
Sign in to try this model with €5 free credits.
Sign in
Press Cmd+Enter to send
Response appears here.
TL;DR·Last updated March 4, 2026

GPT-4o Mini is text & chat AI model from OpenAI, priced at €1.50 per 1M input tokens with a 128K tokens context window.

Try GPT-4o Mini

0.7

Sign in to generate — 50 free credits on sign-up

Examples

See what GPT-4o Mini can generate

Quick Summary

Summarize the key points of the Agile methodology in 3 bullet points

1) Agile emphasizes iterative development, delivering working software in short cycles called sprints rather than one big release. 2) It prioritizes collaboration between cross-functional teams and stakeholders, with regular feedback loops. 3) Agile embraces change—requirements can evolve throughout the project based on user feedback and shifting priorities.

Email Draft

Write a professional email declining a meeting invitation due to a scheduling conflict

Subject: Re: Meeting Invitation – Schedule Conflict Hi [Name], Thank you for the invitation. Unfortunately, I have a prior commitment at that time and won't be able to attend. I'd love to stay in the loop—could you share the meeting notes afterward? Alternatively, I'm available on Thursday afternoon if rescheduling works for the group. Best regards

Pricing

Price per Generation
Per generationFree

API Integration

Use our OpenAI-compatible API to integrate GPT-4o Mini into your application.

Install
npm install railwail
JavaScript / TypeScript
import railwail from "railwail";

const rw = railwail("YOUR_API_KEY");

// Simple — just pass a string
const reply = await rw.run("gpt-4o-mini", "Hello! What can you do?");
console.log(reply);

// With message history
const reply2 = await rw.run("gpt-4o-mini", [
  { role: "system", content: "You are a helpful assistant." },
  { role: "user", content: "Explain quantum computing simply." },
]);
console.log(reply2);

// Full response with usage info
const res = await rw.chat("gpt-4o-mini", [
  { role: "user", content: "Hello!" },
], { temperature: 0.7, max_tokens: 500 });
console.log(res.choices[0].message.content);
console.log(res.usage);
Specifications
Context window
128,000 tokens
Max output
16,384 tokens
Avg. latency
800ms
Developer
OpenAI
Category
Text & Chat
Tags
fast
affordable

Deep dive — OpenAI's GPT-4o Mini

About OpenAI
Founded 2015 · San Francisco, USA

OpenAI was founded in December 2015 as a non-profit AI research lab by Sam Altman, Elon Musk, Greg Brockman, Ilya Sutskever, Wojciech Zaremba and John Schulman. In 2019 it transitioned to a capped-profit structure (OpenAI LP) to take Microsoft investment, now totalling over $13 billion. Foundational publications include the GPT series papers (GPT-1 through GPT-4), the InstructGPT/RLHF paper (2022) and the GPT-4o System Card (2024). The company ships ChatGPT (launched November 2022), the GPT API, the o-series reasoning models, Sora for video, DALL-E for images and Whisper for speech recognition. Sam Altman remains CEO; Greg Brockman is President. OpenAI's 2025 valuation exceeded $300 billion and the company employs more than 1,500 staff in San Francisco, London, Tokyo, Dublin and other offices. The mission statement focuses on building safe and beneficial AGI for all of humanity.

Visit OpenAI
Architecture
Decoder-only Transformer (small natively multimodal)

GPT-4o mini was announced in July 2024 as a low-cost, fast replacement for GPT-3.5 Turbo. It is a small natively multimodal Transformer derived from the same training stack as GPT-4o, supporting text and vision input with text output. The model was trained on a multi-trillion-token web-scale corpus including code, books, licensed text and image-text pairs, with a knowledge cutoff of October 2023. Post-training combined supervised fine-tuning with RLHF and direct preference optimisation on smaller curated datasets. OpenAI applied an 'instruction hierarchy' training method to better resist jailbreaks and prompt injections by distinguishing system, developer and user instructions during alignment. At launch GPT-4o mini scored 82% on MMLU and outperformed GPT-3.5 Turbo on the Chatbot Arena leaderboard while costing approximately 60% less. It supports the full GPT-4o feature set including function calling, parallel tool calls, JSON mode, Structured Outputs and vision input. The model is the default backbone for ChatGPT Free as of mid-2024 and is widely used as a router and cheap tool-calling layer in agentic systems. Fine-tuning was opened to developers in late 2024 with both supervised fine-tuning and reinforcement fine-tuning options on the API.

Parameters
Undisclosed (estimated ~8B-20B parameters dense)
Context
128K tokens
What it can do
  • Very low cost per token (around $0.15 input / $0.60 output per 1M tokens at launch)
  • 128K context window with 16K max output
  • Vision input for images and PDFs
  • Function calling and parallel tool calls
  • Structured Outputs with strict JSON schema
  • 82% MMLU at launch (better than GPT-3.5 Turbo)
  • Trained with instruction hierarchy to resist prompt injection
  • Supervised and reinforcement fine-tuning available
  • Fast time-to-first-token for chat workloads
  • Multilingual coverage but optimised for English
  • Best for: cheap chatbots, classification, large-scale data labeling, agent routers, customer support.
Training & License

Pretrained on OpenAI's curated multi-trillion-token mixture of web text, code, books and image-text pairs, with a knowledge cutoff of October 2023. Post-training uses supervised fine-tuning, RLHF and the instruction-hierarchy alignment objective.

License: Proprietary, accessible via OpenAI API and Azure OpenAI Service. Commercial use permitted under OpenAI Terms.

Known limitations
  • Weaker reasoning than full GPT-4o on hard math and multi-step problems
  • Higher hallucination rate than larger flagship models
  • Knowledge cutoff October 2023
  • No audio input or output
  • Vision quality below full GPT-4o on complex charts

Frequently asked questions

Start using GPT-4o Mini today

Get started with free credits. No credit card required. Access GPT-4o Mini and 100+ other models through a single API.