Tool and File Words: API Key, JSON, CSV, Markdown and OCR

As soon as you move from chatting with AI to connecting it with other apps, a new set of words appears: API, API key, JSON, CSV. They come from the world of software, so courses often use them without explaining. They are much simpler than they sound.

What You'll Learn

• What an API and an API key are, and how to keep a key safe
• What JSON, CSV and Markdown files look like
• What OCR does
• What plugins, extensions, integrations and credentials are
• What free tier, rate limit and credits mean

API

Meaning: "Application Programming Interface". A way for one app to ask another app to do something, without a person clicking buttons.

Everyday picture: a waiter in a restaurant. You (one app) give your order to the waiter (the API), the waiter takes it to the kitchen (another app) and brings back your food (the result).

Example: an automation tool like Zapier or Make sends your email text to an AI through its API and gets a summary back.

You'll see it: in automation and app-building courses, such as AI Automation Fundamentals.

API key

Meaning: a long secret code that proves an app is allowed to use an API. It is like a password for apps, and it is often linked to billing.

Example: sk-... followed by a long string of letters and numbers.

Keep it safe:

• Never share it in a chat, a screenshot, a public post or a public code project.
• If you think it leaked, delete it in the provider's dashboard and create a new one.
• Set a spending limit if the provider allows it.

Do you need one? Not for normal chat apps. You only need an API key when you connect AI to another tool or write code. Some providers give free API usage with limits; others charge per use.

JSON

Meaning: "JavaScript Object Notation". A simple text format for organized data, made of names and values inside curly brackets. Apps use it to send data to each other.

Example:

{
  "name": "Priya",
  "course": "AI Essentials",
  "completed": true
}

Each line has a name in quotes, a colon, and a value.

You'll see it: when a lesson asks the AI to "reply in JSON" so another app can read the answer, and in automation tools. You do not need to write it by hand; you just need to recognize it.

CSV

Meaning: "Comma-Separated Values". A plain text file that stores a table: each line is a row, and commas separate the columns.

Example:

name,course,score
Priya,AI Essentials,92
Arjun,Python Basics,85

You'll see it: whenever you download data from a website or upload a table to ChatGPT, Claude or Google Sheets. Excel and Sheets open CSV files as normal spreadsheets.

Markdown

Meaning: a simple way to format text with symbols. A # makes a heading, **word** makes bold, and - at the start of a line makes a bullet point.

Example: AI chatbots write their answers in Markdown, which is why you sometimes see ** or # symbols when you copy an answer into a plain text box.

Tip: to remove them, ask the AI: "Give me plain text with no Markdown symbols."

OCR

Meaning: "Optical Character Recognition". Technology that reads text from an image or a scanned page and turns it into text you can copy and edit.

Example: you take a photo of handwritten notes or a printed receipt, and the AI turns it into typed text. Google Lens and most AI chat apps can do this.

Plugin, extension and integration

These three words all mean "an add-on that connects tools", with small differences:

• Extension: an add-on for your web browser, like a grammar checker in Chrome.
• Plugin: an add-on inside another app that gives it new features.
• Integration or connector: a link between two apps so they can share data, like connecting an AI assistant to your Google Drive.

You'll see it: in "AI tools" lessons. Before you connect an app to your accounts, check what it can access.

Credentials

Meaning: the details that prove who you are or what an app is allowed to do, like a username and password, an API key or a login token.

You'll see it: in automation tools, which ask you to "add credentials" to connect your accounts. Treat all credentials like passwords.

Free tier, plan, credits and rate limit

• Tier or plan: a level of service, usually free, then paid levels. "Free tier" means the free version.
• Credits: units you spend each time you generate something, especially for images, video and voice.
• Rate limit or usage limit: the most you can use in a time window, like a number of messages per few hours.

Example: "You've reached your limit, try again at 5 PM" is a rate limit on a free tier. For real numbers on popular tools, see Claude Free vs Pro vs Max or ChatGPT Free vs Plus vs Pro.

A quick reference

Key Takeaways

• An API lets apps talk to each other, and an API key is the secret password for it; never share a key.
• JSON stores organized data as names and values, and CSV stores tables as text with commas.
• Markdown is the symbol formatting chatbots use, and OCR reads text from images.
• Extensions, plugins and integrations add features or connect apps; check what they can access.
• Tiers, credits and rate limits describe how much of a tool you can use.