Perplexity API

Overview

Perplexity AI provides LLM inference augmented with real-time web search. Unlike standard LLMs limited to training data, Perplexity's online models fetch and synthesize current web information on every query. Responses include citations to source URLs. The API is fully OpenAI-compatible — use the openai SDK with a custom base_url.

Setup

pip install openai  # Perplexity uses OpenAI-compatible API

export PERPLEXITY_API_KEY=pplx-...

Available Models

Model	Type	Best For
sonar	Online	Fast web-augmented answers
sonar-pro	Online	Deep research, complex queries
sonar-reasoning	Online	Step-by-step reasoning + search
sonar-reasoning-pro	Online	Advanced reasoning + deep search
r1-1776	Offline	No search, uncensored reasoning

Online models search the web on every request. Offline models use only training data.

Instructions

Basic Query with Web Search

from openai import OpenAI

client = OpenAI(
    api_key="pplx-...",  # or os.environ["PERPLEXITY_API_KEY"]
    base_url="https://api.perplexity.ai",
)

response = client.chat.completions.create(
    model="sonar",
    messages=[
        {
            "role": "system",
            "content": "Be precise and concise. Always cite your sources.",
        },
        {
            "role": "user",
            "content": "What are the latest developments in quantum computing as of today?",
        },
    ],
)

print(response.choices[0].message.content)

Accessing Citations

from openai import OpenAI

client = OpenAI(
    api_key="pplx-...",
    base_url="https://api.perplexity.ai",
)

response = client.chat.completions.create(
    model="sonar-pro",
    messages=[{"role": "user", "content": "What is the current price of Bitcoin?"}],
)

# Main answer
print(response.choices[0].message.content)

# Citations are in the extra_fields / model_extra
if hasattr(response, "citations"):
    for i, citation in enumerate(response.citations, 1):
        print(f"[{i}] {citation}")

# Or access via model_extra
citations = getattr(response, "citations", [])
for url in citations:
    print(f"Source: {url}")

Streaming with Citations

from openai import OpenAI

client = OpenAI(
    api_key="pplx-...",
    base_url="https://api.perplexity.ai",
)

stream = client.chat.completions.create(
    model="sonar",
    messages=[{"role": "user", "content": "Summarize the top tech news today."}],
    stream=True,
)

for chunk in stream:
    if chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)
print()

Deep Research with sonar-pro

from openai import OpenAI

client = OpenAI(
    api_key="pplx-...",
    base_url="https://api.perplexity.ai",
)

# sonar-pro performs more web searches for comprehensive answers
response = client.chat.completions.create(
    model="sonar-pro",
    messages=[
        {
            "role": "system",
            "content": "You are a research analyst. Provide detailed, well-sourced analysis.",
        },
        {
            "role": "user",
            "content": (
                "Provide a comprehensive analysis of the current state of "
                "AI regulation globally, including recent legislation and upcoming proposals."
            ),
        },
    ],
    max_tokens=2000,
)

print(response.choices[0].message.content)

Reasoning with sonar-reasoning

from openai import OpenAI

client = OpenAI(
    api_key="pplx-...",
    base_url="https://api.perplexity.ai",
)

# sonar-reasoning shows chain-of-thought + searches web
response = client.chat.completions.create(
    model="sonar-reasoning",
    messages=[
        {
            "role": "user",
            "content": (
                "Based on current market data, should I invest in NVIDIA or AMD stock? "
                "Consider recent earnings and market trends."
            ),
        }
    ],
)

print(response.choices[0].message.content)
# Response includes <think> blocks with reasoning process

Multi-Turn Research Session

from openai import OpenAI

client = OpenAI(
    api_key="pplx-...",
    base_url="https://api.perplexity.ai",
)

messages = [
    {
        "role": "system",
        "content": "You are a research assistant with access to current web information. "
                   "Always cite sources and indicate when information may be time-sensitive.",
    }
]

def research_chat(user_message: str) -> str:
    messages.append({"role": "user", "content": user_message})
    
    response = client.chat.completions.create(
        model="sonar-pro",
        messages=messages,
    )
    
    answer = response.choices[0].message.content
    messages.append({"role": "assistant", "content": answer})
    return answer

# Multi-turn research
print(research_chat("What are the main AI labs releasing models in 2025?"))
print(research_chat("Which of those models are available via API right now?"))
print(research_chat("Compare their pricing per million tokens."))

Rate Limiting & Error Handling

from openai import OpenAI, RateLimitError
import time

client = OpenAI(
    api_key="pplx-...",
    base_url="https://api.perplexity.ai",
)

def search_with_retry(query: str, retries: int = 3) -> str:
    for attempt in range(retries):
        try:
            response = client.chat.completions.create(
                model="sonar",
                messages=[{"role": "user", "content": query}],
                timeout=30,
            )
            return response.choices[0].message.content
        except RateLimitError:
            wait = 2 ** attempt
            print(f"Rate limited. Retrying in {wait}s...")
            time.sleep(wait)
    raise Exception("Max retries exceeded")

Online vs Offline Models

Feature	Online (sonar*)	Offline (r1-1776)
Web search	✅ Real-time	❌ Training data only
Citations	✅ URL sources	❌ Not applicable
Current events	✅ Up to today	❌ Training cutoff
Latency	Higher (~2–5s)	Lower (~0.5s)
Cost	Higher	Lower

Use online models when freshness matters. Use offline models for tasks that don't need current data (reasoning, creative writing, code).

Guidelines

• Online models search the web on every request — expect 2–5 second latency.
• Citations appear in the response.citations list (URLs).
• sonar is fastest for simple lookups; sonar-pro does multiple searches for complex topics.
• Perplexity's search is English-centric but supports other languages.
• For real-time price data or stock quotes, combine Perplexity with direct API calls for accuracy.
• The system prompt cannot disable web search for online models — use offline models if you need pure LLM responses.
• Token costs include search overhead — budget accordingly for high-volume use.