LLM Invoice Extraction: Cost Comparison & Implementation Guide

Short summary

A bootcamp grad processes 200+ invoice PDFs using LLM APIs with structured output, finding cheaper models (DeepSeek V4 Flash, GLM-4 Plus) achieve 94%+ accuracy matching GPT-4o while costing ~9x less. Includes working Python code, temperature tuning for deterministic output, and cost comparison across six providers. Key takeaway: open models often outperform flagship options on price-to-quality ratio for domain-specific document processing.

• •DeepSeek V4 Flash achieved 94% accuracy on 50-invoice test (47/50 correct) vs GPT-4o's 98% at 9x lower cost
• •Provided working Python code using OpenAI SDK with Global API endpoint, showing temperature=0 ensures deterministic output
• •Detailed pricing shows 40-65% cost reduction vs flagship models; tokens roughly equal 4 characters of text

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