Codex by OpenAI
AI that writes code for you
Not Diamond
The last chatbot you’ll ever need
Updated February 2026
| Codex by OpenAI | Not Diamond | |
|---|---|---|
| Rating | 5.0★ | 3.0★ |
| Reviews | 20 | 2 |
| Pros | 0 | 0 |
| FactScore™ | 66.1 | 14.3 |
FactScore™ Comparison
FactScore™ weighs both quality (rating) and popularity (reviews) for a fairer ranking than stars alone.
Pros & Cons
Only in Codex by OpenAI — Pros
No unique pros listedBoth tools — Pros
—Only in Not Diamond — Pros
No unique pros listedOnly in Codex by OpenAI — Cons
—Both tools — Cons
—Only in Not Diamond — Cons
—Details
| Codex by OpenAI | Not Diamond | |
|---|---|---|
| Categories | AI Coding Agents | AI Coding Agents, AI Chatbots, AI Infrastructure Tools |
| Platforms | Web | Web |
| Became Popular | August 10, 2021 | August 1, 2024 |
| Website | openai.com | chat.notdiamond.ai |
Who Should Pick Which?
Choose Codex by OpenAI if...
- No unique pros listed
Choose Not Diamond if...
- No unique pros listed
With a FactScore™ of 66.1 vs 14.3, Codex by OpenAI leads in community reception. Codex by OpenAI uniquely offers No unique pros listed, while Not Diamond stands out for No unique pros listed.
What Users Say
Codex by OpenAI
Even with new models around, Codex remains one of the most reliable AI coding assistants—fast, structured, and still very useful.
Still the fastest way to get a working regex or a complex utility function from a single-line comment.
OpenAI Codex has become an essential part of our development workflow. With our AGENTS.md providing project context, Codex understands our monorepo architecture and coding conventions, autonomously...
Not Diamond
I will say that at the beginning it was a very cool AI. But then after the last update all pro models were blocked, which suited me, I wanted to switch to a pro account, but they introduced a limit...
Related Comparisons
Frequently Asked Questions
Which is better, Codex by OpenAI or Not Diamond?
Based on FactScore™, Codex by OpenAI leads with a score of 66.1 vs 14.3. Codex by OpenAI has a higher rating of 5.0★ compared to 3.0★.
What are the pros of Codex by OpenAI compared to Not Diamond?
Codex by OpenAI uniquely offers: No unique pros listed.
What are the pros of Not Diamond compared to Codex by OpenAI?
Not Diamond uniquely offers: No unique pros listed.
Is Codex by OpenAI better rated than Not Diamond?
Codex by OpenAI is rated 5.0★ from 20 reviews. Not Diamond is rated 3.0★ from 2 reviews.
What is the FactScore™ of Codex by OpenAI and Not Diamond?
FactScore™ weighs rating and review volume together. Codex by OpenAI scores 66.1 and Not Diamond scores 14.3.
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