OpenAI Codex Mini vs GPT-4o (Omni)

Compare OpenAI Codex Mini and GPT-4o (Omni), both from OpenAI, context windows of 200K vs 128K, tested across 10 shared challenges. Updated April 2026.

Which is better, OpenAI Codex Mini or GPT-4o (Omni)?

OpenAI Codex Mini and GPT-4o (Omni) are both competitive models. OpenAI Codex Mini costs $1.5/M input tokens vs $2.5/M for GPT-4o (Omni). Context windows: 200K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between OpenAI Codex Mini and GPT-4o (Omni)

OpenAI Codex Mini is made by openai while GPT-4o (Omni) is from openai. OpenAI Codex Mini has a 200K token context window compared to GPT-4o (Omni)'s 128K. On pricing, OpenAI Codex Mini costs $1.5/M input tokens vs $2.5/M for GPT-4o (Omni).

Our Verdict
OpenAI Codex Mini
OpenAI Codex Mini
GPT-4o (Omni)
GPT-4o (Omni)

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call
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OpenAI Codex MiniGPT-4o (Omni)

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
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