How to Use Your Own OpenAI API Key in Zapier

AI by Zapier is convenient but limited and shares pooled credits. If you want a specific model, longer context, or full control over cost, connect your own OpenAI account. This guide covers creating an API key, adding it to Zapier, and using the OpenAI app as an action.

What you need

• A Zapier account
• An OpenAI account with billing set up at platform.openai.com
• Permission to create an API key on that account
• About 10 minutes

Step 1: Create an OpenAI API key

Sign in at platform.openai.com, open the API keys page from your account menu, and click Create new secret key. Name it something like zapier-prod. Copy the key right away because OpenAI only shows it once.

Step 2: Add the OpenAI app in Zapier

In a Zap, add an action and search for OpenAI (sometimes labeled ChatGPT by Zapier). Choose the Conversation or Send Prompt action. When it asks to connect an account, paste your secret key. Zapier validates it and stores it as a connected account you can reuse across Zaps.

Step 3: Pick a model and write the prompt

In the action settings, select a model from the dropdown such as gpt-4o-mini for cheap fast work or gpt-4o for harder tasks. Set a low max tokens value to cap cost, then map your trigger fields into the user message box.

{
  "model": "gpt-4o-mini",
  "max_tokens": 300,
  "temperature": 0.3,
  "user_message": "Rewrite this support reply to be friendly and concise:\n{{Body}}"
}

Step 4: Test, then reuse the connection

Test the step and confirm the response comes back. Every future Zap that needs OpenAI can now select this same connected account, so you only enter the key once. Watch your usage on the OpenAI dashboard for the first few days.

Result: Your Zaps now call GPT directly on your own billing, letting you choose models and control spend instead of relying on shared Zapier AI credits.