OpenAI Setup
How to create an OpenAI account, get your API key, set up billing, and configure GPT-5.6 and other OpenAI models in LinkedGrow.
Overview
OpenAI provides the GPT-5.6 family, made up of Sol, Terra and Luna, alongside GPT-5.5 and the GPT-5.4 models. All of them write LinkedIn content well, and the range covers everything from a fraction of a cent per post to premium quality.
Step 1 - Create an OpenAI account
- Go to platform.openai.com
- Click Sign up if you do not have an account
- Verify your email address
Step 2 - Set up billing
Before you can use the API, you need to add a payment method:
- Go to your OpenAI dashboard
- Navigate to Settings > Billing
- Click Add payment method
- Enter your credit or debit card details
- Set a monthly spending limit if you want one, and $10 covers most users comfortably
OpenAI bills pay-as-you-go, so you are only charged for what you actually use, and there is no minimum deposit.
Step 3 - Generate your API key
- Go to platform.openai.com/api-keys
- Click Create new secret key
- Give it a name, for example "LinkedGrow"
- Click Create
- Copy the key immediately, because it starts with
sk-and will not be shown again
Important: Save your key somewhere safe. If you lose it, you will need to generate a new one.
Step 4 - Configure in LinkedGrow
- Go to Settings > AI API in LinkedGrow
- Click the OpenAI tab
- Paste your API key in the key field
- Select a model from the dropdown
- Click Save
Available models
| Model | Best for | Cost per post | Monthly estimate (30 posts) |
|---|---|---|---|
| GPT-5.6 Sol | Highest quality, hardest reasoning | ~$0.04 | ~$1.20 |
| GPT-5.6 Terra (Recommended) | Balanced quality and cost | ~$0.02 | ~$0.66 |
| GPT-5.6 Luna | Fast, cheap drafting work | ~$0.002 | ~$0.07 |
| GPT-5.5 | Complex professional writing | ~$0.06 | ~$1.80 |
| GPT-5.4 | Reliable, well tested quality | ~$0.03 | ~$0.90 |
| GPT-5.4 mini | Best value in the older lineup | ~$0.008 | ~$0.25 |
| GPT-5.4 nano | Cheapest option available | ~$0.002 | ~$0.07 |
Recommendation: GPT-5.6 Terra is the model LinkedGrow marks as recommended and the right starting point for most people. It writes solid LinkedIn posts for about 2 cents each. Move down to GPT-5.6 Luna when volume matters more than polish, or up to GPT-5.6 Sol when quality matters more than the bill.
Pricing details
OpenAI bills by token, and 1,000 tokens covers roughly 750 words.
| Model | Input (per 1M tokens) | Output (per 1M tokens) |
|---|---|---|
| GPT-5.6 Sol | $4.00 | $20.00 |
| GPT-5.6 Terra | $2.00 | $12.00 |
| GPT-5.6 Luna | $0.20 | $1.20 |
| GPT-5.5 | $5.00 | $30.00 |
| GPT-5.4 | $2.50 | $15.00 |
| GPT-5.4 mini | $0.75 | $4.50 |
| GPT-5.4 nano | $0.20 | $1.25 |
How reasoning affects your bill
Every GPT-5 model reasons before it answers, and OpenAI bills those reasoning tokens at the output rate. LinkedGrow sets the reasoning effort to low on every request, which keeps a single post from costing several times the headline rate. You do not need to configure anything for this.
Key format
OpenAI API keys start with sk- followed by a long string of characters. If your key does not start with sk-, double check that you copied it correctly.
Monitoring your spending
Track your API usage and costs at platform.openai.com/usage. You can set monthly spending limits in Billing settings to prevent unexpected charges.
Image generation
OpenAI also supports image generation through GPT Image 2, with GPT Image 1.5, GPT Image 1 and GPT Image 1 Mini kept as legacy choices. The same API key works for text and images. See Image Providers for details on setting up image AI.