Relay Platform Selection: Navigating the 71x Output Price Gap Between DeepSeek V4 and GPT-5.5

When GPT-5.5 output tokens cost $30.00/MTok and DeepSeek V4 output sits at $0.42/MTok, the math forces every team to rethink its inference routing. This guide opens with a head-to-head comparison table, walks through ROI on a 500M-token monthly workload, and shows how to ship a routing layer that picks the right model per request — using HolySheep as the unified OpenAI-compatible base URL.

The 71x Output Price Reality Check

Before picking any relay, baseline the published list prices. The table below uses vendor pricing pages as of January 2026.