DeepSeek V3 vs Claude 3.5 Sonnet: Coding Benchmark & API Cost Comparison (2026)

import os
from openai import OpenAI
import anthropic

# Initialize DeepSeek client via OpenAI-compatible endpoint
deepseek_client = OpenAI(
    api_key=os.environ.get("DEEPSEEK_API_KEY"),
    base_url="https://api.deepseek.com"
)

# Initialize Anthropic client for frontier fallback
anthropic_client = anthropic.Anthropic(
    api_key=os.environ.get("ANTHROPIC_API_KEY")
)

def run_coding_task(prompt: str, requires_deep_reasoning: bool = False):
    """Cost-optimized routing: DeepSeek-V3 first, escalate to Sonnet if needed."""
    if not requires_deep_reasoning:
        try:
            response = deepseek_client.chat.completions.create(
                model="deepseek-chat", # DeepSeek-V3
                messages=[{"role": "user", "content": prompt}],
                temperature=0.2,
                max_tokens=4096
            )
            return {
                "provider": "deepseek",
                "cost_est": "$0.003",
                "content": response.choices[0].message.content
            }
        except Exception as e:
            print(f"DeepSeek failed or rate-limited: {e}. Escalating to Claude...")

    # Fallback / Escalation to Claude 3.5 Sonnet
    response = anthropic_client.messages.create(
        model="claude-3-5-sonnet-20241022",
        max_tokens=4096,
        messages=[{"role": "user", "content": prompt}]
    )
    return {
        "provider": "anthropic",
        "cost_est": "$0.045",
        "content": response.content[0].text
    }