The LLM API landscape in 2026 is dramatically different from 12 months ago. Prices dropped 10x, speed increased 5x, and a dozen serious contenders now compete with GPT-4. Here's your no-BS guide to choosing the right one. The Short Comparison Table Model Input $/1M Output $/1M Best For DeepSeek V4 $0.27 $1.10 Cost-efficient agents GPT-4o $2.50 $10.00 Vision, ecosystem GPT-4o mini $0.15 $0.60 High-volume cheap tasks Claude Sonnet 4 $3.00 $15.00 Long docs, coding Gemini 2.5 Pro $1.25 $10.00 Ultra-long context (1M tokens) Gemini 2.0 Flash $0.10 $0.40 Fastest Google Llama 3.3 70B (Groq) $0.59 $0.79 Fastest inference Mistral Large 2 $2.00 $6.00 EU data residency 1. OpenAI — The Default Standard Every framework, SDK, and tutorial defaults to OpenAI's API. Vision, function calling, Batch API (50% discount), Realtime API. If you're unsure, start here. When to use: Teams needing vision, compliance (SOC 2/HIPAA), or broadest ecosystem support. 2. DeepSeek V4 — Best Price-Performance The biggest story of 2026.…