How to use OpenAI API Key for AI chat
Ann Ng
OpenAI (ChatGPT)About OpenAI (ChatGPT)
ChatGPT is OpenAI's conversational AI assistant now powered by the latest GPT-5 family of models released in 2025, featuring unified multimodal capabilities across text, images, and audio with advanced reasoning.
The current lineup includes GPT-5 (flagship general-purpose model with real-time routing, faster responses, reduced hallucinations, and customizable personalities), o3 (advanced reasoning model for complex math, science, and programming with 88.9% AIME accuracy), o4-mini (cost-efficient reasoning at scale with 92.7% AIME accuracy), and GPT-5-Codex (specialized for dynamic coding tasks).
Key features include autonomous tool use (web browsing, code execution, file operations), self-fact checking, multimodal unification, and variants from Nano to Pro for different use cases.
Step by step guide to use OpenAI API Key to chat with AI
1. Get Your OpenAI API Key
First, you'll need to obtain an API key from OpenAI. This key allows you to access their AI models directly and pay only for what you use.
- Visit OpenAI's API console
- Sign up or log in to your account
- Navigate to the API keys section
- Generate a new API key (copy it immediately as some providers only show it once)
- Save your API key in a secure password manager or encrypted note
2. Connect Your OpenAI API Key on TypingMind
Once you have your OpenAI API key, connecting it to TypingMind to chat with AI is straightforward:
- Open TypingMind in your browser
- Click on the "Settings" icon (gear symbol) in the sidebar
- Navigate to "API Keys" section
- Find the OpenAI (ChatGPT) configuration area
- Paste your API key in the designated OpenAI field
- Click "Save" to verify the key works and store your configuration
3. Start Chatting with OpenAI models
Now you can start chatting with OpenAI (ChatGPT) models through TypingMind:
- Select your preferred OpenAI model from the model dropdown menu
- Start typing your message in the chat input
- Enjoy faster responses and better features than the official interface
- Switch between different AI models as needed
gpt-5- Use specific, detailed prompts for better responses (How to use Prompt Library)
- Create AI agents with custom instructions for repeated tasks (How to create AI Agents)
- Use plugins to extend OpenAI capabilities (How to use plugins)
- Upload documents and images directly to chat for AI analysis and discussion (Chat with documents)
4. Monitor Your AI Usage and Costs
One of the biggest advantages of using API keys with TypingMind is cost transparency and control. Unlike fixed subscriptions, you pay only for what you actually use. Visit https://platform.openai.com/usage to monitor your OpenAI API usage and set spending limits.
| Feature | OpenAI Subscription Plans | Using OpenAI API Keys |
|---|---|---|
| Cost Structure | ❌ Fixed monthly fee Pay even if you don't use it ChatGPT Plus:$20/month ChatGPT Pro:$200/month | ✅ Pay only for actual usage $0 when you don't use it |
| Usage Limits | ❌ Hard daily/hourly caps You have to wait for the next period to use it again | ✅ Unlimited usage No limits. Only limited by your budget |
| Model Access | ❌ Platform decides available models Old models get discontinued | ✅ Access to all API models Including older & specialized versions |
- Use less expensive models for simple tasks
- Keep prompts concise but specific to reduce token usage
- Use TypingMind's prompt caching to reduce repeat costs (How to enable prompt caching)
- Using RAG (retrieval-augmented generation) for large documents to reduce repeat costs (How to use RAG)
Mistral: Mistral NemoAccess Mistral: Mistral Nemo via OpenRouter
A 12B parameter model with a 128k token context length built by Mistral in collaboration with NVIDIA. The model is multilingual, supporting English, French, German, Spanish, Italian, Portuguese, Chinese, Japanese, Korean, Arabic, and Hindi. It supports function calling and is released under the Apache 2.0 license.
OpenAI: GPT-4o-mini (2024-07-18)Access OpenAI: GPT-4o-mini (2024-07-18) via OpenRouter
GPT-4o mini is OpenAI's newest model after [GPT-4 Omni](/models/openai/gpt-4o), supporting both text and image inputs with text outputs. As their most advanced small model, it is many multiples more affordable than other recent frontier models, and more than 60% cheaper than [GPT-3.5 Turbo](/models/openai/gpt-3.5-turbo). It maintains SOTA intelligence, while being significantly more cost-effective. GPT-4o mini achieves an 82% score on MMLU and presently ranks higher than GPT-4 on chat preferences [common leaderboards](https://arena.lmsys.org/). Check out the [launch announcement](https://openai.com/index/gpt-4o-mini-advancing-cost-efficient-intelligence/) to learn more. #multimodal
OpenAI: GPT-4o-miniAccess OpenAI: GPT-4o-mini via OpenRouter
GPT-4o mini is OpenAI's newest model after [GPT-4 Omni](/models/openai/gpt-4o), supporting both text and image inputs with text outputs. As their most advanced small model, it is many multiples more affordable than other recent frontier models, and more than 60% cheaper than [GPT-3.5 Turbo](/models/openai/gpt-3.5-turbo). It maintains SOTA intelligence, while being significantly more cost-effective. GPT-4o mini achieves an 82% score on MMLU and presently ranks higher than GPT-4 on chat preferences [common leaderboards](https://arena.lmsys.org/). Check out the [launch announcement](https://openai.com/index/gpt-4o-mini-advancing-cost-efficient-intelligence/) to learn more. #multimodal
Google: Gemma 2 27BAccess Google: Gemma 2 27B via OpenRouter
Gemma 2 27B by Google is an open model built from the same research and technology used to create the [Gemini models](/models?q=gemini). Gemma models are well-suited for a variety of text generation tasks, including question answering, summarization, and reasoning. See the [launch announcement](https://blog.google/technology/developers/google-gemma-2/) for more details. Usage of Gemma is subject to Google's [Gemma Terms of Use](https://ai.google.dev/gemma/terms).
Google: Gemma 2 9B (free)Access Google: Gemma 2 9B (free) via OpenRouter
Gemma 2 9B by Google is an advanced, open-source language model that sets a new standard for efficiency and performance in its size class. Designed for a wide variety of tasks, it empowers developers and researchers to build innovative applications, while maintaining accessibility, safety, and cost-effectiveness. See the [launch announcement](https://blog.google/technology/developers/google-gemma-2/) for more details. Usage of Gemma is subject to Google's [Gemma Terms of Use](https://ai.google.dev/gemma/terms).
Google: Gemma 2 9BAccess Google: Gemma 2 9B via OpenRouter
Gemma 2 9B by Google is an advanced, open-source language model that sets a new standard for efficiency and performance in its size class. Designed for a wide variety of tasks, it empowers developers and researchers to build innovative applications, while maintaining accessibility, safety, and cost-effectiveness. See the [launch announcement](https://blog.google/technology/developers/google-gemma-2/) for more details. Usage of Gemma is subject to Google's [Gemma Terms of Use](https://ai.google.dev/gemma/terms).
Anthropic: Claude 3.5 Sonnet (2024-06-20)Access Anthropic: Claude 3.5 Sonnet (2024-06-20) via OpenRouter
Claude 3.5 Sonnet delivers better-than-Opus capabilities, faster-than-Sonnet speeds, at the same Sonnet prices. Sonnet is particularly good at: - Coding: Autonomously writes, edits, and runs code with reasoning and troubleshooting - Data science: Augments human data science expertise; navigates unstructured data while using multiple tools for insights - Visual processing: excelling at interpreting charts, graphs, and images, accurately transcribing text to derive insights beyond just the text alone - Agentic tasks: exceptional tool use, making it great at agentic tasks (i.e. complex, multi-step problem solving tasks that require engaging with other systems) For the latest version (2024-10-23), check out [Claude 3.5 Sonnet](/anthropic/claude-3.5-sonnet). #multimodal
Sao10k: Llama 3 Euryale 70B v2.1Access Sao10k: Llama 3 Euryale 70B v2.1 via OpenRouter
Euryale 70B v2.1 is a model focused on creative roleplay from [Sao10k](https://ko-fi.com/sao10k). - Better prompt adherence. - Better anatomy / spatial awareness. - Adapts much better to unique and custom formatting / reply formats. - Very creative, lots of unique swipes. - Is not restrictive during roleplays.
Mistral: Mistral 7B Instruct (free)Access Mistral: Mistral 7B Instruct (free) via OpenRouter
A high-performing, industry-standard 7.3B parameter model, with optimizations for speed and context length. *Mistral 7B Instruct has multiple version variants, and this is intended to be the latest version.*
Mistral: Mistral 7B InstructAccess Mistral: Mistral 7B Instruct via OpenRouter
A high-performing, industry-standard 7.3B parameter model, with optimizations for speed and context length. *Mistral 7B Instruct has multiple version variants, and this is intended to be the latest version.*
Mistral: Mistral 7B Instruct v0.3Access Mistral: Mistral 7B Instruct v0.3 via OpenRouter
A high-performing, industry-standard 7.3B parameter model, with optimizations for speed and context length. An improved version of [Mistral 7B Instruct v0.2](/models/mistralai/mistral-7b-instruct-v0.2), with the following changes: - Extended vocabulary to 32768 - Supports v3 Tokenizer - Supports function calling NOTE: Support for function calling depends on the provider.
NousResearch: Hermes 2 Pro - Llama-3 8BAccess NousResearch: Hermes 2 Pro - Llama-3 8B via OpenRouter
Hermes 2 Pro is an upgraded, retrained version of Nous Hermes 2, consisting of an updated and cleaned version of the OpenHermes 2.5 Dataset, as well as a newly introduced Function Calling and JSON Mode dataset developed in-house.
