API (Application Programming Interface)

Definition

A way to access AI tools programmatically via HTTP requests.

Why It Matters

Every web-based AI tool, including this site, talks to its model through an API. Once you have an API key, you can do everything the website does, plus automate it in scripts, run it in a loop, or wire the model into your own product.

Key Points

• REST APIs use HTTP verbs: GET (read), POST (create/run), PUT/PATCH (update), DELETE (remove).
• Auth is almost always a bearer token in the Authorization header, never a query parameter.
• Rate limits (requests-per-minute) and quota limits (tokens-per-day) are independent; you can hit either before the other.
• Streaming responses use Server-Sent Events (SSE) with Content-Type: text/event-stream; each chunk arrives as a data: line.
• OpenAI's /v1/chat/completions JSON shape has become the de-facto standard; most providers support it for compatibility.

Example

POST /v1/chat/completions on Rewind.ai accepts the same JSON shape OpenAI publishes. A 20-line Python script using `requests` and your bearer token gets identical responses to what the chat page shows in the browser.

Related Terms

• InferenceThe process of running an AI model to generate a response. When you send a message to ChatGPT, the model performs inference.
• LLM (Large Language Model)A neural network trained on massive text datasets that can generate, understand and manipulate human language. Examples: GPT-4, Qwen, Claude.
• Open Source AIAI models released with open licenses (MIT, Apache 2.0) allowing anyone to use, modify and deploy them.

Quick Facts