Perplexity is an AI answer engine that searches the web when you ask a question and writes a response with numbered source links. The bottom line: it is smaller than ChatGPT and Gemini by user share, but it is built around retrieval and citation, it publishes an API, and its source choices are more community and review driven than its competitors, so it matters for businesses whose buyers research products and services.

For a full definition, read our answer engine optimization guide.

What it is

Perplexity was founded in 2022 as a search product that answers in prose and shows its sources. Unlike a chatbot that answers mostly from training, it retrieves pages for each question. Its Sonar models are documented as combining real time web search with natural language generation and returning citations, and developers can call them through an API alongside OpenAI's web search tool and Gemini's Google Search grounding.

How big it is

A June 2026 tracker, reported by Cheers from First Page Sage, put Perplexity at 2.7 percent of the standalone generative AI chatbot market, behind ChatGPT at 53.1 percent, Claude at 21.1 percent, Gemini at 13.1 percent, and Copilot at 8.7 percent. That is a secondary report of one tracker, but the ordering is consistent with G2's finding that ChatGPT was used by 63 percent of B2B software buyers for research. Perplexity's smaller reach means its value to a business depends on whether its buyers use it, which research and technical audiences often do.

How it chooses sources

AspectWhat is known
IndexPerplexity says it operates its own index of more than 200 billion URLs
CrawlersPerplexityBot for the index and Perplexity-User for user requests, with Perplexity saying the latter generally does not follow robots.txt
Source mixReddit was about 46.7% of its top source share in Profound's analysis, and commercial answers leaned on G2, Gartner, NerdWallet, PCMag, TripAdvisor, and Yelp
FreshnessAhrefs found Perplexity and Gemini showed a strong recency preference, less than ChatGPT

What it means for a business

  1. Decide whether your buyers use it. Ask new customers, or check referral traffic from perplexity.ai.
  2. Allow PerplexityBot. It is a search crawler, and blocking it removes you from its index.
  3. Build the sources it reads. Review profiles, honest community participation, and comparison content.
  4. Test your questions in Perplexity. Run each five times and record the sources cited.

Limits of what is known

Perplexity does not publish how it ranks sources. The citation studies cited here come from third parties, sample different questions, and disagree on percentages. Use them for the pattern, and confirm with your own runs.

Questions people ask

What is Perplexity AI?

An AI answer engine, founded in 2022, that searches the web for each question and writes a response with numbered source links.

How does Perplexity choose its sources?

It runs real time searches against its own index and shows the sources it used. Studies find it leans on Reddit, review sites, and news, but Perplexity does not publish its ranking method.

Should my business care about Perplexity?

If your buyers research products and services, likely yes, but its user share is smaller than ChatGPT's. Check your referral traffic and ask customers.

Does Perplexity respect robots.txt?

Its index crawler, PerplexityBot, does. Perplexity says its user fetcher, Perplexity-User, generally does not.

Sources