Pick a winner in each dimension — change your vote anytime.
Pricing and capabilities synced from the OpenRouter catalogue. Scores are editorial (0–10).
Choose Gemini 3.5 Flash if you want high-throughput agents that need big context cheaply. Choose GPT-5.3-Codex if you want codex CLI users and dedicated coding agents.
In our editorial scoring, Gemini 3.5 Flash leads in 4 of five dimensions (output quality, speed, value for $ and reliability), while GPT-5.3-Codex leads in 1. On price, Gemini 3.5 Flash runs about $3.75 per 1M tokens (blended) and is proprietary; GPT-5.3-Codex is about $5.42 and proprietary.
The model picks the moves; the agent runs the loop, the tools, and the guardrails. Once you've chosen a model, see which agent gets the most out of it.