# Web scraping and data glossary

> Simple meanings of web scraping, data and automation terms: Actor, dataset, crawler, API, proxy, MCP, RAG, browser extension and more.

URL: https://cliqtomedia.com/glossary/

This **web scraping glossary** explains common words in plain English. New to all this? Read the 8 words below first.

## The 8 words you need first
| Word | What it means |
|---|---|
| [Apify](#apify) | The cloud platform where our tools run. You make a free account there. Apify bills you, not us. |
| [Actor](#actor) | One tool on Apify. It does one job, like reading job ads or prices. |
| [Scraper](#scraper) | A tool that copies data from web pages into a table. |
| [Input](#input-schema) | The form you fill in before you start: links, words, numbers. |
| [Run](#run) | One start of a tool. You press Start, it works, then it stops. |
| [Dataset](#dataset) | The table with the results of a run. |
| [Export](#csv) | Download the table as Excel, CSV or JSON. |
| [Pay per event](#pay-per-event) | You pay a small price for each result, plus a small fee for each run. |

All other words are below, in groups. Use your browser search (Ctrl+F or Cmd+F) to find a word fast. For the full steps, see [How it works](/actors/how-it-works/).

## How to use this web scraping glossary
| Group | Words about |
|---|---|
| [Web scraping basics](#basics) | Scrapers, crawlers, pages, SEO data |
| [Apify terms](#apify) | Actors, runs, datasets, tasks, pricing |
| [Data formats](#formats) | JSON, CSV, Excel, Markdown, RSS |
| [Access, blocking and proxies](#access) | Proxies, limits, status codes |
| [Automation terms](#automation) | Schedules, monitors, integrations |
| [Business data terms](#marketing) | Leads, signals, monitoring, listening, CRM |
| [AI and LLM terms](#ai) | LLMs, MCP, RAG, OCR, transcripts |
| [Browser extension terms](#extensions) | Extensions, Chrome Web Store, local storage |

## Web scraping basics
These are the main **web scraping terms**. You will see them on almost every tool page.

### Web scraping
Web scraping means using a program to read data from web pages. The program saves the data in a table or a file. For example, it saves the title and price of every product on a page. All our [Actors](/actors/) do some kind of web scraping or data collection.

### Scraper
A scraper is a program that takes data out of web pages. It finds the parts you need, like names, prices or dates. Then it saves them as clean fields. Example: [TrustRadius Reviews Scraper](/actors/trustradius-reviews-scraper/).

### Web crawler
**What is a web crawler?** A crawler is a program that finds pages by following links. It starts at one page and visits the links on it, again and again. A scraper then takes data from the pages the crawler found. [Website to Markdown for RAG: Crawl & Changed Pages](/actors/website-to-markdown/) crawls a docs site and saves each page.

### Headless browser
**What is a headless browser?** It is a web browser with no window. Programs use it to open pages that need JavaScript. It sees the page like a real user does. It is slower than a simple request, so good tools use it only when needed.

### HTML
HTML is the code that web pages are made of. It uses tags like `<h1>` for titles and `<a>` for links. Scrapers read the HTML to find data. Readers do not see the HTML, only the page it builds.

### JavaScript rendering
Some pages build their content with JavaScript after they load. A simple scraper sees an empty page. A headless browser runs the JavaScript first, then reads the full page. Some of our tools have a "render JavaScript" option for this.

### URL
A URL is the address of a web page, like `https://example.com/page`. Most tools take a list of URLs as input. Always use the full URL with `https://`.

### Pagination
Pagination means that results are split over many pages, like page 1, 2, 3. A good scraper follows the pages for you. You set how many results you want, and the tool stops there.

### Structured data
Structured data is data with clear fields and types. For example: `"price": 19.99`, `"currency": "EUR"`. It is easy to sort, filter and use in Excel or AI. Our Actors always return structured data.

### JSON-LD
JSON-LD is a way to add structured data inside a web page. Sites use it to tell search engines about products, events, recipes and more. It sits in a hidden `<script>` tag. [Website JSON-LD Structured Data Scraper](/actors/website-jsonld-structured-data-scraper/) reads it for you.

### Open Graph
Open Graph is a set of meta tags in a page. They tell social apps which title, text and image to show when someone shares a link. Example tag: `og:title`. [Website Metadata & Open Graph Scraper](/actors/website-metadata-open-graph-scraper/) collects these tags.

### Metadata
Metadata is "data about data". For a web page, it is the title, the description, the language and more. For a video, it is the length, the date and the view count.

### Sitemap
A sitemap is a file that lists the pages of a website. Most sitemaps are XML files, like `/sitemap.xml`. They help search engines and tools find every page fast. Try [XML Sitemap URLs Extractor](/actors/xml-sitemap-urls-extractor/).

### robots.txt
**What is robots.txt?** It is a text file at the root of a website, like `example.com/robots.txt`. It tells bots which pages they should not visit. It also often links to the sitemap. Good tools respect it.

### SERP
SERP means **search engine results page**. It is the page you see after you search on Google or Bing. It has links, ads, and boxes like "People also ask". See [Google Search Results Scraper (SERP) - No Login, Per Page](/actors/google-search-scraper/) and [Search, SEO & ads](/actors/search-seo/).

### ATS
ATS means **applicant tracking system**. Companies use an ATS to post jobs and manage candidates. Greenhouse, Lever, Ashby and Workable are ATS tools. Our [Jobs & hiring](/actors/jobs/) tools read public job boards from many ATS.

### API
An API is a way for programs to talk to each other and share data, without a person clicking. (API stands for *application programming interface*.) Some sites have an official API. Apify also has an API to run tools from your code.

### Public data
Public data is data anyone can see without a login or payment. Most of our tools read only public data. Still, check each site's terms and your local law. See our [FAQ](/faq/).

## Apify terms
[Apify](https://apify.com?fpr=cliqto) is the cloud platform where our Actors run. These words come from Apify.

### Actor
**What is an Apify Actor?** An Actor is a cloud program on Apify. It takes input, does one task and saves the results. Our Apify tools are all Actors. Read more in [How it works](/actors/how-it-works/).

### Apify Store
The [Apify Store](https://apify.com/store?fpr=cliqto) is a marketplace of ready-made Actors. Many developers publish tools there, including us. You can find all our Actors on our [Apify profile](https://apify.com/cliqtomedia?fpr=cliqto).

### Apify Console
Console is the Apify website where you run Actors. There you see your runs, datasets, tasks, schedules and bills. You open it after you sign in.

### Input schema
The input schema is the list of fields an Actor accepts. Apify uses it to build the input form. It also sets default values and checks your input before the run.

### Run
A run is one start of an Actor. Each run has a status, a log and its own storage. Example statuses: Running, Succeeded, Failed.

### Log
The log is the list of messages an Actor writes while it works. It tells you what the tool did, what it skipped and why. Read the log first when a run fails.

### Dataset
**What is a dataset?** A dataset is the table where a run saves its results. Each row is one item, like one job or one review. You can export it to CSV, JSON, Excel and more. How long unnamed datasets stay depends on your Apify plan and settings. Name a dataset or export it to keep your data.

### Key-value store
A key-value store is a place to save files and single records for a run. For example, a screenshot, a PDF or a run summary. Each record has a name (the key) and content (the value).

### Task
A task is a saved input for one Actor. You fill the form once and save it with a name. Then you can run it again, schedule it or connect it to apps.

### Schedule
A schedule starts Actors or tasks at set times. For example, every day at 08:00. Apify schedules use cron rules and your timezone.

### Webhook
A webhook is a message that Apify sends to a URL when something happens. For example, when a run succeeds. Your app can then load the results. See [Integrations](/actors/integrations/).

### API token
An API token is a secret key for your Apify account. Code, apps and AI agents use it to run tools for you. Keep it private, like a password. You find it in Console under Settings → API & Integrations.

### Pay per event
Pay per event is a pricing model on Apify. You pay a small fixed price for each event, like a run start or one saved result. The developer sets the events and prices. See [Pricing](/actors/pricing/).

### Pay per result
Pay per result means you pay for each row a tool saves. It is a simple type of pay per event. No results, no result fees.

### Compute unit
A compute unit (CU) measures computer work on Apify. One CU is 1 GB of memory for one hour. For most pay-per-event tools, you do not need to think about CUs.

### Memory
Memory is how much computer power a run gets. More memory can make a run faster, but it can also cost more on usage-based tools. Our tools come with good default settings.

## Data formats
These are the file types you can export from a dataset.

### JSON
JSON is a text format for data. It uses names and values in curly brackets, like `{"name": "Anna", "age": 30}`. It is the main format for APIs, code and AI tools.

### JSONL
JSONL means "JSON Lines". Each line of the file is one JSON object. It is good for very big files, because programs can read it line by line.

### CSV
CSV means **comma-separated values**. It is a simple table in a text file. Each line is a row, and commas split the columns. Excel and Google Sheets open it easily.

### Excel (XLSX)
XLSX is the file type of Microsoft Excel. Apify can export a dataset directly as XLSX. Use it when your team works in Excel.

### XML
XML is an older text format with tags, a bit like HTML. Some business systems and sitemaps still use it.

### Markdown
Markdown is plain text with simple marks. For example, `#` makes a heading and `-` makes a list. AI models read it very well. See [Fast Webpage to Markdown API for AI Agents](/actors/webpage-to-markdown-api/).

### RSS
RSS is a feed format that lists the newest posts of a site. Atom is a similar format. News apps and feed readers use them. Try [RSS & Atom Feed Reader / Monitor](/actors/rss-atom-feed-reader-monitor/).

## Access, blocking and proxies
Websites protect themselves from too many bots. These words explain how.

### IP address
An IP address is the number that identifies a computer on the internet. Websites see the IP of every visitor. Many requests from one IP can look like a bot.

### Proxy
**What is a proxy in web scraping?** A proxy is a server between your tool and the website. The website sees the proxy's IP address, not yours. Tools use proxies to spread requests, so no single address sends too many. Apify has its own proxy service.

### Datacenter proxy
A datacenter proxy uses an IP address from a cloud company. It is fast and cheap. But some sites block these IPs more often.

### Residential proxy
A residential proxy uses an IP address from a normal home internet connection. It is slower and costs more than a datacenter proxy.

### Rate limit
A rate limit is the maximum number of requests a site or API allows in a time. For example, 60 requests per minute. Good tools slow down to stay under the limit.

### CAPTCHA
A CAPTCHA is a test that checks if you are a human. For example, "click all pictures with a bus". Sites show it when they think a visitor is a bot.

### User agent
The user agent is a short text that a browser sends to a site. It says which browser and system you use. Sites may block requests with strange user agents.

### HTTP status code
A status code is a number a website sends back for each request. `200` means OK, `404` means not found, `429` means too many requests. Check many links at once with [Link Route Audit — Bulk HTTP Status & Redirects](/actors/bulk-url-status-redirect-checker/).

### Redirect
A redirect sends a visitor from one URL to another. For example, from `http://` to `https://`. Codes `301` and `302` mean redirects.

### Login wall
A login wall means you must sign in to see the data. Most of our Actors need **no login** and read public pages. Some, like eBay sold listings, need your own session or an API key.

### Terms of service
Terms of service are the rules of a website. Some terms limit scraping or reuse of data. Read them before you collect data. This is not legal advice.

## Automation terms
These words help you run tools without clicks.

### Cron
Cron is a short code for times. For example, `0 8 * * 1` means "every Monday at 08:00". Apify schedules use cron, and also simple words like `@daily`.

### Integration
An integration connects two apps so data moves between them. For example, Apify and Google Sheets. See [Integrations](/actors/integrations/).

### Make, Zapier and n8n
These are no-code automation tools. You connect blocks: a trigger, then actions. Each has an Apify app or node to run our tools and load results.

### Trigger
A trigger is the event that starts an automation. For example, "a run finished" or "a new row was added".

### Monitor
A monitor runs again and again and looks for changes. Our monitor tools mark rows as new, changed or removed since the last run. Example: [GitHub Releases Monitor & Scraper](/actors/github-releases-monitor-scraper/).

### Baseline
A baseline is the saved "last state" that a monitor compares with. The first run creates the baseline. Later runs show what changed since then.

### Deduplication
Deduplication means removing rows that appear twice. For example, the same job on two pages. Our tools try to save each item only once.

### Client library
A client library is ready-made code for an API. Apify has official clients for Python and JavaScript. They make it easy to run tools from your code.

## Business data terms
These words often come up when you work with web data. Many of them link to a use case page.

### Marketing data
Marketing data means facts about your market: leads, prices, reviews, keywords and what people say online. Our Actors can collect this data for you. See [all use cases](/actors/use-cases/).

### Lead generation
Lead generation means finding people or companies that may buy from you. A lead list is a table of names, websites and contacts. See [lead lists](/actors/use-cases/lead-generation/).

### Lead enrichment
Lead enrichment means adding facts to a lead you already have. For example, an email, a phone number, a tech stack or a company size.

### Buying signal
A buying signal is a sign that a company may need your product soon. For example, new jobs, new funding or a new tool on its site. See [buying signals](/actors/use-cases/buying-signals/).

### Competitor monitoring
Competitor monitoring means you watch what other companies in your market do. For example, new pages, new prices, new products or new jobs. See [competitor watch](/actors/use-cases/competitor-monitoring/).

### Price monitoring
Price monitoring means you check product prices in shops on a schedule. You see when a price goes up or down. See [price tracking](/actors/use-cases/price-monitoring/).

### Review monitoring
Review monitoring means you collect new reviews about your brand from many sites in one place. Then you can reply fast. See [review monitoring](/actors/use-cases/review-monitoring/).

### Social listening
Social listening means you track what people say about a brand, a product or a topic on social sites and forums. See [social listening](/actors/use-cases/social-listening/).

### Content repurposing
Content repurposing means you turn one piece of content into many. For example, a video becomes a blog post, a newsletter and social posts. See [content repurposing](/actors/use-cases/content-repurposing/).

### Creator outreach
Creator outreach means you find bloggers, YouTubers or podcasters for a campaign and contact them. See [creator outreach](/actors/use-cases/creator-outreach/).

### CRM
A CRM is an app that keeps your contacts, companies and deals. Examples are HubSpot, Pipedrive and Salesforce. Our tools can send new rows to a CRM.

## AI and LLM terms
These words come up when you use web data with AI. See also [AI agents](/actors/ai-agents/).

### LLM
LLM means **large language model**. It is an AI model that reads and writes text. ChatGPT, Claude and Gemini are built on LLMs.

### AI agent
An AI agent is an AI model that can use tools. It can search, open pages, run Actors and save files. It plans steps to reach a goal.

### MCP
MCP means **Model Context Protocol**. It is an open standard that connects AI apps to tools. The [Apify MCP server](https://mcp.apify.com/?fpr=cliqto) lets AI apps use Apify Actors, including ours.

### RAG
**What is RAG?** RAG means **retrieval-augmented generation**. An AI model first finds useful text, then uses it to answer. This gives better, fresher answers. Try [RAG Web Search: Google Results as Clean Markdown](/actors/rag-web-search/).

### Embedding
An embedding is a list of numbers that shows the meaning of a text. Texts with similar meaning get similar numbers. RAG systems use embeddings to find the right text.

### Vector database
A vector database stores embeddings. It can find texts with a similar meaning very fast. RAG apps keep their chunks here.

### Chunk
A chunk is a small piece of a long text, like one section of a page. AI apps split long documents into chunks. [PDF to Markdown for LLMs & RAG Chunks - No Login](/actors/pdf-to-markdown/) returns ready chunks.

### Token
A token is a small piece of a word. LLMs count text in tokens. Prices and limits of AI models are often per token. Clean Markdown uses fewer tokens than raw HTML.

### Prompt
A prompt is the text you give an AI model. It can be a question or an instruction. Clear prompts with good data give better answers.

### Hallucination
A hallucination is when an AI model makes up facts. Fresh, real data from the web helps the model stay correct.

### OCR
OCR means **optical character recognition**. It reads text from images and scanned PDFs. Try [PDF & Image to Text OCR for AI Agents - No Login](/actors/pdf-text-ocr/).

### Transcript
A transcript is the written text of a video or audio file. It can include times for each line. See [YouTube Subtitles & Transcript Scraper API](/actors/youtube-transcript-scraper/) and [Video, audio & streaming](/actors/video-audio/).

### Speech to text
Speech to text turns spoken words into written text. It is how you get a transcript when a video has no subtitles. Try [Audio & Podcast Transcriber (Speech to Text)](/actors/audio-video-transcriber/).

### LLM-ready data
LLM-ready data is clean data that AI models can read easily. It has no menus, ads or cookie banners. Markdown and JSON are the best formats. See [AI-ready content & documents](/actors/ai-content/).

This web scraping glossary grows with our tools. When we add a new kind of tool, we add its words here too.

## Browser extension terms
### Browser extension
A browser extension is a small program that adds a feature to your browser. Our [browser extensions](/extensions/) run on your own computer.

### Chrome Web Store
The Chrome Web Store is Google's official shop for Chrome extensions. You install extensions from it with one click.

### Manifest V3
Manifest V3 is the current set of rules for Chrome extensions. It limits what an extension can do. This keeps you safer.

### Content script
A content script is extension code that runs on one website. For example, [Bulk Post Scheduler for X](/extensions/x-bulk-scheduler/) works only on x.com.

### Local extension storage
Local extension storage keeps data inside your browser, for example in IndexedDB. It does not go to a server. Bulk Post Scheduler for X keeps your queue there.

## Questions

### What is web scraping?
Web scraping means using a program to read data from web pages. The program saves the data in a table or file.

### What is the difference between a crawler and a scraper?
A crawler finds pages by following links. A scraper takes data from the pages.

### What is a headless browser?
It is a web browser with no window. Programs use it to open pages that need JavaScript.

### What is robots.txt?
It is a file on a website. It tells bots which pages they should not visit.

### What is RAG?
RAG means retrieval-augmented generation. An AI model first finds useful text, then uses it to answer.

### What is an Apify Actor?
An Actor is a cloud program on Apify. It takes input, does a task and saves the results in a dataset.

### What is a proxy in web scraping?
A proxy is a server between the tool and the website. The site sees the proxy's IP address. It helps spread requests.

### What is the difference between JSON and CSV?
JSON keeps data with names and can hold lists inside fields. CSV is a flat table. Use CSV for Excel and JSON for code.

### What is a dataset on Apify?
A dataset is the results table of a run. Each row is one result. You can export it in many formats.

### Is web scraping legal?
It depends on the data, the site's terms and your country's law. Public data is often fine to read. Ask a lawyer for your case. This is not legal advice.

### Is a word missing here?
[Tell us](/contact/). We add new terms often.

Now you know the words. Try a tool and see them in action.

[See our Apify Actors](/actors/) [How it works](/actors/how-it-works/)