# Perplexity AI

Perplexity AI is a search engine that uses large language models (LLMs) to answer queries using sources from the web and cites links within the text response. Its developer, Perplexity AI, Inc., is based in San Francisco, California.

## History

Perplexity was founded in 2022 by Aravind Srinivas, Andy Konwinski, Denis Yarats and Johnny Ho, engineers with backgrounds in back-end systems, artificial intelligence (AI) and machine learning.
As of April 2024, Perplexity had raised $165 million in funding, valuing the company at over $1 billion. As of December 2024, Perplexity closed a $500 million round of funding that elevated its valuation to $9 billion. Investors in Perplexity AI have included Jeff Bezos, Nvidia, and Databricks. In July 2024, Perplexity announced the launch of a new publishers' program to share ad revenue with partners.
In October 2024, The New York Times sent a cease-and-desist notice to Perplexity to stop accessing and using NYT content, claiming that Perplexity is violating its copyright by scraping data from its website.
On January 18, 2025, the day before the impending U.S. ban on Chinese social media app TikTok, Perplexity submitted a proposal for a merger with TikTok US.

## Services

Perplexity works on a freemium model. It also offers a paid enterprise version.
The free model used the company's standalone LLM based on GPT-3.5 with browsing. The default free model uses the Sonar API based on lightweight models. Perplexity summarizes the search results and produces text with inline citations and also enables users to use Pages to generate customizable web pages and research presentations based on user prompts.
The pro version provides access to an API where users can search both internal files and web content. It also has access to the OpenAI family models (including OpenAI o3-mini, GPT-4o and GPT-4.5), Claude 3.7 Sonnet, Gemini Flash 2.0, Llama 3, Deepseek R1 and in-house models Sonar and R1 1776

### Shopping hub

On November 18, 2024, Perplexity launched its shopping hub to attract users, backed by Amazon and leading AI chipmaker Nvidia. This will give users product cards showing relevant items in response to asked questions about shopping.

### Internal Knowledge Search

Internal Knowledge Search enables Pro and Enterprise Pro users to simultaneously search across web content and internal documents. Users can upload and search through Excel, Word, PDF, and other common file formats. Enterprise Pro users have a limit of 500 files for upload and indexing.

### Finance

In October 2024, Perplexity AI introduced new finance-related features, including looking up stock prices and company earnings data. The tool provides real-time stock quotes and price tracking, industry peer comparisons and basic financial analysis tools. The platform sources its financial data from Financial Modeling Prep (FMP) to ensure accuracy.

### Assistant for Android

In January 2025, Perplexity launched the Perplexity Assistant, an AI-powered tool designed to enhance the functionality of its search engine. The assistant is available on Android devices and is integrated into the Perplexity app. It can perform tasks across multiple apps, such as hailing a ride or searching for a song, and is capable of maintaining context across actions, allowing for more seamless task management.
The Perplexity Assistant is powered by the company's search engine, granting it access to the web. This enables event reminders, including finding the right date and time and creating corresponding calendar entries. The assistant is also multi-modal, meaning it can use a phone's camera to provide answers about the user's surroundings or on-screen content.
Initially, the Perplexity Assistant is free in 15 languages, including English, Spanish, French, German, Japanese, Polish, Korean, and Hindi. Despite its promising features, Perplexity has acknowledged that the assistant is still in development and may not always function as expected. For instance, certain features, such as summarizing unread emails or upcoming calendar events, require users to enable a workaround based on notifications.

## Controversies
### Forbes investigation

In June 2024, Forbes publicly criticized Perplexity for using their content. According to Forbes, Perplexity published a story largely copied from a proprietary Forbes article without mentioning or prominently citing Forbes. In response, Srinivas said that the feature had some "rough edges" and accepted feedback but maintained that Perplexity only "aggregates" rather than plagiarizes information.

### Wired investigation

In June 2024, separate investigations by the magazine Wired and web developer Robb Knight found that Perplexity does not respect the robots.txt standard, which allows websites to stop web crawlers from scraping content, reportedly despite Perplexity claiming the opposite. Perplexity also lists the IP address ranges and user agent strings of their web crawlers publicly, but according to Wired and Robb Knight, they use undisclosed IP addresses and spoofed user agent strings when ignoring robots.txt. In response, Srinivas stated that Perplexity is not ignoring Robot Exclusion Protocol. When asked whether Perplexity would cease scraping Wired content using third parties, Srinivas responded that "it's complicated."

## Lawsuits
### Dow Jones and New York Post

The same month, Dow Jones and New York Post filed a lawsuit against Perplexity, alleging copyright infringement. The lawsuit also alleges that Perplexity attributed quotes to an article on F-16 jets for Ukraine that never appeared in the original article.
On October 24, 2024, Perplexity released a blog post to address the lawsuits. It stated that the complaints are misleading and reiterated that it was open to revenue-sharing programs.

### Perplexity Solved Solutions

On January 31, 2025, Perplexity was sued for alleged trademark infringement by Perplexity Solved Solutions (PSS), a software firm founded in 2017. The lawsuit, filed in the United States, claims that Perplexity AI's use of the name "Perplexity" violates PSS's federally registered trademark, potentially leading to consumer confusion. PSS had previously declined an offer from Perplexity AI to purchase the trademark in 2023. The legal action seeks to prevent Perplexity AI from using the name in its branding and marketing.