API

Technical terms
About 1 min read

A standard interface for exchanging data and functionality between software applications. In AI, it serves as a core tool to connect cloud-hosted Large Language Models (LLMs) to external apps, enabling immediate implementation of features like text generation and image analysis.

Also known as
Application Programming InterfaceApplication Programming Interface

Detailed explanation

An API (Application Programming Interface) is an intermediary that helps different software programs communicate with each other. When choosing AI tools, APIs serve as the conduit for embedding a model's intelligence into a service. When a user sends a prompt, the model server performs inference via the API and returns the result back to the application. Modern AI APIs go beyond basic text exchange, offering advanced interfaces such as 'Streaming' for real-time responses, 'Batch processing' for cost reduction, and 'Enterprise-only endpoints' for enhanced security. Furthermore, token-based pricing structures and data security policies (such as Zero Data Retention) have become key criteria for tool selection.

Choosing an AI API directly impacts service quality and profitability. Alongside model performance (IQ), factors like 'Latency,' 'Token Pricing,' and 'Rate Limits' are critical. In particular, a compliance review is essential to ensure that corporate data is not reused for model training.

Why It Matters in Tool Selection

What to Check

  • Cost per input/output token and whether caching discounts apply
  • Is the Time to First Token (TTFT) suitable for the user experience?
  • Whether there is a security policy (Zero Data Retention) that does not use API call data for model training
  • Does it support Batch APIs for bulk processing to reduce costs?

Example

When a user enters a question into a chatbot UI, the application internally uses an API key to send data to OpenAI's 'gpt-4o' endpoint. The server generates a response, returns it in JSON format, and the application parses this data to display it on the screen.

Commonly Confused Terms

API vs SDK

While an API is a protocol for communication, an SDK is a development kit that bundles libraries and tools to make using that API easier.

REST vs Streaming

REST delivers a single response to a single request, whereas streaming delivers responses in real-time chunks as they are generated.

Related terms

SDKTokenRESTWebhook