Instructor creator Jason Liu asks developers why they still rely on ChatGPT over OpenAI Codex
Story Overview
Jason Liu, the Instructor library creator now working on OpenAI's Codex team, turned to developers with a direct question about lingering ChatGPT habits even as Codex handles more code-specific work. Early replies surfaced two concrete differences rather than vague preferences, highlighting where the tools still diverge in practice.
Pro model stays behind ChatGPT's door
Replies noted that the higher-accuracy GPT-5.5 Pro variant launched exclusively inside ChatGPT for Pro and higher tiers, with no Codex availability confirmed at rollout. This leaves some users routing harder tasks through the chat interface while keeping Codex for dedicated coding flows.
One engineer flags ATLAS as daily driver
Andrew Mayne answered the same query with a single word, ATLAS, pointing to the AI browser's integration for summaries, agentic browsing, and web-based reasoning that sits outside Codex's workspace focus. Broader patterns around this choice remain open in the thread.
Users praise Codex mobile support for on-the-go prototyping while negative users criticize its rate limits, combined billing, and weaker non-coding performance versus ChatGPT.
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Most Activity
Codex really is the superapp and spans everything I can think of doing. Especially because of the mobile support
If you use Codex, is there any reason you still use ChatGPT?
what do you use it for? how has it been better or critical for you?
@jxnlco 5.5 Pro is still only available in ChatGPT.
If you use Codex, is there any reason you still use ChatGPT?
what do you use it for? how has it been better or critical for you?
Codex feels like ChatGPT Pro. That is probably the best way I could describe it.
If you use Codex, is there any reason you still use ChatGPT?
what do you use it for? how has it been better or critical for you?
@jxnlco I ain't burning my codex rate limits for an email response
@jxnlco Best-in-class remote desktop access
If you use Codex, is there any reason you still use ChatGPT?
what do you use it for? how has it been better or critical for you?
@jxnlco Definitely. Mostly when I want to look at a problem without the access and bias of seeing the current code
@jxnlco Better for instant answer, one-off things just more accessible.
Also for Pro inference. Still not sure why I don’t have that in codex and I need a third party connector to get that working.
@jxnlco I ain’t asking codex random questions that consume a usage limit. ChatGPT is my Google replacement, just more interactive.
Codex is for work
@jxnlco Absolutely. Everything starts with ChatGPT. ChatGPT maintains the context. For my projects, I use the connector to Warp so ChatGPT can "see" what Codex is doing. I've built a MCP server just so ChatGPT can audit the deliverables locally. Codex is the worker, ChatGPT is the lead.
@chrisalbon Except that 5.5 Pro can only be used in ... ChatGPT! 🫠
Codex feels like ChatGPT Pro. That is probably the best way I could describe it.
@jxnlco I bounce ideas off ChatGPT and they help me create artifacts when needed.
ChatGPT is also my every day assistant. I speak with ChatGPT over 20 hours a week managing a variety of tasks that Codex cannot.
I can make a list of examples if you'd like.
@jxnlco Well, first of all, ChatGPT works when Codex usage is used.
Secondly, it can generate images
Thirdly, I do have questions not related to code bases
@jxnlco ATLAS.
If you use Codex, is there any reason you still use ChatGPT?
what do you use it for? how has it been better or critical for you?
@jxnlco web search is better on it than codex. especially for long outputs and using many sources to cite. and access from anywhere (e.g. in the hospital/Clinic)
@jxnlco I use both, codex for building things and automate stuff, ChatGPT for theoretical work, research, planing, reminding me stuff, keep eye on specific things, analyzing things... Both have their own unique purpose.
@AverageAiBro @jxnlco Do side chats use up usage?
@jxnlco Because I cannot use it on the mobile app or web easily like ChatGPT for basic conversations and one-off queries.
@jxnlco Can’t access ChatGPT finances in codex, can’t use pro models in codex, and on the go codex mobile is nice but the main ChatGPT interface has had a lot more love & works when computer is offline
Personalized advice. I journal every day into ChatGPT, which builds its context about me. The more it knows, the better it personalizes. Then I ask it for advice, and it crushes it. Simple example: "Here are a bunch of cheeses. Which one would I like?" It's introduced me to a bunch of cheeses that I've loved, because it knows so much about me.
@jxnlco Codex feels like a productive workspace where I go to automate tasks, work on coding projects, and have AI handle computer-related tasks. ChatGPT is where I go to explore ideas, ask questions, learn, and study. I'm not bound to Codex limits on ChatGPT—feels less punishing to chat