What Is Perplexity AI, and When Should You Use It?

You ask a question
        ↓
Perplexity rewrites it into one or more search queries
        ↓
It searches the web and ranks the best pages
        ↓
A language model reads the top results
        ↓
It writes an answer with numbered citations [1] [2] [3]
        ↓
You click a citation to check the source

Getting better answers out of it

Ask a question, not a keyword. "Best laptop" gets you a generic list. "Best 14-inch laptop under $1,200 for .NET development with 32 GB RAM, and why" gets you something you can act on, because the constraints do the filtering.

Then use the thread. Perplexity keeps the context, so "compare the top two", "what changed this year?" or "show only sources from the last six months" all work as follow-ups without restating the question.

Match the mode to the job. Quick search is fine for facts and simple questions. Research mode earns its wait when the answer needs many sources. Computer is the one to use when the output should be a file or a finished task rather than an answer.

Finally, look at the citations. Hover over or click the numbers, and prefer primary sources such as official docs, filings and vendor announcements over aggregators. If a key claim has no citation at all, treat it as unverified. Prompts like these play to its strengths, because each one asks for a specific, citable source:

What changed in the latest .NET release for minimal APIs? Cite the official docs.
Compare EF Core and Dapper for bulk inserts, with benchmarks from the last year.
Is CVE-XXXX-YYYY exploitable in ASP.NET Core 9? Link the advisory.

Using the Perplexity API

Perplexity sells its search and answer technology through a pay-as-you-go API with no subscription required. The API quickstart lists four products as of October 2026:

API	What it does	Endpoint
Agent API	Web-grounded answers with citations, using Perplexity's tools with third-party models	POST /v1/agent (OpenAI Responses-compatible)
Search API	Ranked web results and page snippets, with no generated answer	POST /search
Orchestrator API	Open-weight models through OpenAI- and Anthropic-compatible endpoints	/orchestrator/v1/chat/completions
Embeddings API	Text embeddings for semantic search and RAG	See docs

If you built on the older Sonar chat completions models, that functionality now lives in the Agent API. Perplexity's pricing page gave September 27, 2026 as the end of Sonar support, so if you haven't migrated, that's the first job.

Calling the Search API from C#

The Search API is the one I'd pick when you already have a model and just want fresh web results to feed into your own RAG pipeline. It costs $5 per 1,000 requests at standard speed.

using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Text.Json;

var apiKey = Environment.GetEnvironmentVariable("PERPLEXITY_API_KEY");

using var http = new HttpClient();
http.DefaultRequestHeaders.Authorization =
    new AuthenticationHeaderValue("Bearer", apiKey);

var response = await http.PostAsJsonAsync(
    "https://api.perplexity.ai/search",
    new { query = "ASP.NET Core rate limiting best practices", max_results = 5 });

response.EnsureSuccessStatusCode();

using var doc = JsonDocument.Parse(await response.Content.ReadAsStringAsync());
foreach (var result in doc.RootElement.GetProperty("results").EnumerateArray())
{
    Console.WriteLine($"{result.GetProperty("title")} - {result.GetProperty("url")}");
}

Calling the Agent API with the OpenAI SDK

Because the Agent API follows the OpenAI Responses format, you can point the OpenAI Python SDK at Perplexity's base URL and keep the rest of your code:

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ.get("PERPLEXITY_API_KEY"),
    base_url="https://api.perplexity.ai/v1",
)

response = client.responses.create(
    model="openai/gpt-5.6-sol",
    input="What are the main changes in the latest C# language version?",
    extra_body={"tools": [{"type": "web_search"}]},
)

print(response.output_text)

The response includes a search_results item with titles, URLs and snippets, and the answer text carries markers such as [web:5] that point back to those results. Call GET /v1/models to see which models are available right now. If you'd rather use Perplexity's own SDKs, they install with pip install perplexityai and npm install @perplexity-ai/perplexity_ai.

Perplexity, ChatGPT or Google?

The three overlap more every year, so the useful question is which one fits the task in front of you.

Need	Perplexity	ChatGPT	Google Search
Current facts with sources	Best fit, with citations on every answer	Good when web search is used	Good, with AI Overviews and AI Mode on top of links
Long writing and brainstorming	Adequate	Best fit	Not designed for it
Finding a specific site, map or shop	Adequate	Adequate	Best fit
Agents that produce files	Computer and Personal Computer	ChatGPT Work and Codex	Gemini agent features, separate from Search
Browser	Comet (free)	Chrome extension (Atlas being retired)	Chrome with Gemini
Entry paid price	$20/month	About $8 (Go) or $20 (Plus)	Search is free; Google AI plans are separate

Put simply: Perplexity for answers you need to trust and check, ChatGPT for creating and working, Google for getting around the web. If the agents are what you're weighing, our comparison of Perplexity and ChatGPT computer agents goes through them side by side.

Where it falls short

The biggest trap is treating a citation as proof. The answer can misstate what a source says, and the sources themselves vary: an SEO content farm or a forum thread can sit right next to the official docs. It also can't read what it can't reach, so paywalled material is mostly out of bounds.

The agents carry a different kind of risk, because Personal Computer and Comet act on your behalf. Keep approvals switched on for email, purchases and deletions, and be wary of web pages that may hide prompt-injection instructions aimed at the assistant.

For company data, use Enterprise Pro or Enterprise Max, which add admin controls and data protections. Perplexity says company data used with Personal Computer is not used to train its models, but check your own organisation's AI policy before anyone connects work files.

And expect the plans to keep moving. Features and limits shift between Free, Pro and Max often enough that anything you read about tiers, including the table above, is worth re-checking before you pay.