perplexity-cost-tuning

Perplexity Cost Tuning

Overview

Reduce Perplexity Sonar API costs. Perplexity charges per-token (input + output) plus a per-request fee that varies by search context size. The biggest cost lever is model selection: sonar-pro costs 3-15x more than sonar per request.

Pricing Reference

Model	Input $/M tokens	Output $/M tokens	Request Fee
sonar	$1	$1	$5 per 1K requests
sonar-pro	$3	$15	$5 per 1K requests
sonar-reasoning-pro	$3	$15	$5 per 1K requests
sonar-deep-research	$2	$8	$5 per 1K searches

Search context size (Low/Medium/High) affects the request fee. More context = higher fee.

Prerequisites

• Perplexity API account with usage dashboard
• Understanding of query patterns in your application
• Cache infrastructure for search results

Instructions

Step 1: Route Queries to the Right Model

// 60-70% of queries can use sonar, saving 3-15x per query
function selectModel(query: string): "sonar" | "sonar-pro" {
  const simplePatterns = [
    /^what is/i, /^define/i, /^who is/i, /^when did/i,
    /current price/i, /^how many/i, /^is it true/i,
  ];
  if (simplePatterns.some((p) => p.test(query))) return "sonar";

  const complexPatterns = [
    /compare.*vs/i, /analysis of/i, /comprehensive/i,
    /pros and cons/i, /in-depth/i, /research/i,
  ];
  if (complexPatterns.some((p) => p.test(query))) return "sonar-pro";

  return "sonar"; // Default to cheapest
}

Step 2: Limit Output Tokens

set -euo pipefail
# Factual queries need ~100 tokens, not 4096
# Setting max_tokens dramatically reduces output costs

# Simple fact: 100 tokens = $0.0001 output
curl -X POST https://api.perplexity.ai/chat/completions \
  -H "Authorization: Bearer $PERPLEXITY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "sonar",
    "messages": [{"role": "user", "content": "Current population of Tokyo"}],
    "max_tokens": 100
  }'

# Research query: keep at 2048 only when needed
curl -X POST https://api.perplexity.ai/chat/completions \
  -H "Authorization: Bearer $PERPLEXITY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "sonar-pro",
    "messages": [{"role": "user", "content": "Compare React vs Vue in 2025 for enterprise apps"}],
    "max_tokens": 2048
  }'

Step 3: Cache to Eliminate Duplicate Queries

import { LRUCache } from "lru-cache";
import { createHash } from "crypto";

const searchCache = new LRUCache<string, any>({
  max: 10000,
  ttl: 4 * 3600_000, // 4-hour default TTL
});

async function cachedQuery(query: string, model: string) {
  const key = createHash("sha256")
    .update(`${model}:${query.toLowerCase().trim()}`)
    .digest("hex");

  const cached = searchCache.get(key);
  if (cached) return cached; // $0 cost

  const result = await perplexity.chat.completions.create({
    model,
    messages: [{ role: "user", content: query }],
  });
  searchCache.set(key, result);
  return result;
}

// Track cache effectiveness
function cacheStats() {
  return {
    size: searchCache.size,
    hitRate: `${((searchCache as any).hits / ((searchCache as any).hits + (searchCache as any).misses) * 100).toFixed(1)}%`,
  };
}

Step 4: Use Domain Filters to Reduce Search Cost

set -euo pipefail
# Restricting search domains = less content to process = lower request fee
curl -X POST https://api.perplexity.ai/chat/completions \
  -H "Authorization: Bearer $PERPLEXITY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "sonar",
    "messages": [{"role": "user", "content": "Python 3.13 release notes"}],
    "search_domain_filter": ["python.org", "docs.python.org"],
    "max_tokens": 500
  }'

Step 5: Track and Budget

class CostTracker {
  private costs: Array<{ model: string; tokens: number; timestamp: Date }> = [];

  record(model: string, usage: { total_tokens: number }) {
    this.costs.push({
      model,
      tokens: usage.total_tokens,
      timestamp: new Date(),
    });
  }

  dailySummary() {
    const today = this.costs.filter(
      (c) => c.timestamp.toDateString() === new Date().toDateString()
    );
    const sonarTokens = today.filter((c) => c.model === "sonar").reduce((s, c) => s + c.tokens, 0);
    const proTokens = today.filter((c) => c.model === "sonar-pro").reduce((s, c) => s + c.tokens, 0);

    return {
      queries: today.length,
      estimatedCost: (sonarTokens * 0.000001) + (proTokens * 0.000009), // rough estimate
      sonarQueries: today.filter((c) => c.model === "sonar").length,
      proQueries: today.filter((c) => c.model === "sonar-pro").length,
    };
  }
}

Cost Optimization Checklist

• Default model is sonar (not sonar-pro)
• max_tokens set on every request
• Caching enabled for repeated queries
• Model routing by query complexity
• Domain filter used where applicable
• Monthly budget cap set on API key
• Cost tracking in production monitoring

Error Handling

Issue	Cause	Solution
High cost per query	Using sonar-pro for everything	Route simple queries to sonar
Low cache hit rate	Queries too unique	Normalize queries before hashing
Budget exhausted early	No spending caps	Set monthly budget on API key
Unexpectedly high bill	No max_tokens limits	Set max_tokens on all requests

Output

• Model routing saving 60-70% on simple queries
• Token limiting reducing output costs
• Caching eliminating duplicate query costs
• Cost tracking for budget monitoring

Resources

• Perplexity Pricing
• Model Cards

Next Steps

For architecture patterns, see perplexity-reference-architecture.