OpenAI Codex CLI vs What The Diff
According to AI Tier List, OpenAI Codex CLI (Tier A) ranks higher than What The Diff (Tier B) for Coding & Development. CLI coding tool included with ChatGPT Plus
 |  | |
|---|---|---|
| Tier | Tier A | Tier B |
| Rating | 4 / 5 | 3 / 5 |
| Pricing | Paid | Freemium |
| Category | Coding & Development | Coding & Development |
| Best For | CLI, Agentic, Async, Cloud Agent | code-review, pull-request, developer-tools, ai-explanation, productivity |
OpenAI Codex CLI — Strengths
Included with ChatGPT Plus (no extra cost), 50% cheaper than Claude, cloud agent mode, GPT-5.1 performance
OpenAI Codex CLI — Weaknesses
Less autonomous than Claude Code, CLI-only, locked into OpenAI ecosystem
What The Diff — Strengths
Clear and concise code change explanations, reduced code review time, improved developer productivity, enhanced understanding of complex PRs
What The Diff — Weaknesses
Potential for AI explanation accuracy variations, possible limitations in specific language/framework support, early-stage service, pricing model uncertainty