API Key
A unique authentication token that identifies you when calling an AI service's API. API keys control access, track usage, and determine billing for programmatic AI tool usage.
Why this matters
If you want to use AI beyond chat interfaces — building apps, automating workflows, or integrating AI into your products — you need API keys. Understanding API keys helps you manage costs, security, and access across multiple AI services.
Real-world example
To use GPT-4o in your app, you create an OpenAI API key at platform.openai.com. Each API call includes your key for billing. Anthropic, Google, and other providers work the same way. Never share your API key publicly — anyone with it can make requests charged to your account.