Can You Use a ChatGPT Subscription With Claude Code?

No. A ChatGPT subscription — whether a personal plan or a business one — does not extend to Claude Code. The two products are from different companies: ChatGPT is from OpenAI, and Claude Code is from Anthropic. Each requires its own account and its own authentication. There is no shared access layer between them.

If you use both tools on the same project, keeping the project context portable becomes practical. Tools like fenbs store project context, rules, and progress outside any one AI app, so both ChatGPT and Claude Code can read the same record through a standard connection.

What a ChatGPT subscription gives you

A ChatGPT subscription from OpenAI gives you access to ChatGPT at chat.openai.com and, depending on your plan, to features like ChatGPT's coding assistance, file uploads, image generation, and developer tools. The subscription is authenticated through your OpenAI account.

If you want to use OpenAI's models through a tool other than ChatGPT — say, a coding assistant or a CLI tool that accepts an API key — that typically requires an OpenAI API key billed separately by usage. A subscription gives you access to the ChatGPT product; it does not automatically grant API access or credit. Check OpenAI's current plan documentation for the exact terms of your plan.

What Claude Code requires

Claude Code is a command-line coding assistant from Anthropic. It requires an Anthropic account and authenticates through Anthropic's own systems. A Claude Code subscription or usage credit is separate from anything OpenAI offers.

Claude Code runs models that Anthropic trains and hosts. It does not accept OpenAI API keys or ChatGPT credentials. The two providers have separate model families, separate pricing, and separate account systems.

Why the authentication boundary exists

OpenAI and Anthropic are independent companies. Each trains its own models, runs its own infrastructure, and manages its own customer accounts. A subscription to one is a commercial relationship with that company alone.

There is no industry-wide pass for AI tools the way a music streaming subscription works across devices. Each AI product authenticates with the company that provides it. This is worth knowing before you compare pricing across tools, because you may end up paying for two separate subscriptions or two separate API usage meters if you use both regularly.

Using ChatGPT and Claude Code together

Many developers use more than one AI assistant on the same codebase. ChatGPT can be useful for research and explanation; Claude Code is well-suited to long editing sessions with file access. The tools complement each other, but they do not share context automatically.

When you switch from one to the other mid-project, the new tool does not know what the previous one did. You end up re-explaining the project, restating decisions, and re-checking what was finished. The more of that context you save externally, the shorter that re-explanation becomes.

What to do if you want to use a different model in Claude Code

Claude Code supports using alternative model providers through configuration. Check Anthropic's current documentation for which providers and models it supports. Using a non-Anthropic model in Claude Code does not require a ChatGPT subscription; it typically requires an API key from the model provider you choose.

The question of routing between models in Claude Code is covered in the claude code router post. For a direct comparison of the two assistants' capabilities, see claude vs chatgpt and claude vs chatgpt for coding.

What project data each tool holds and what it does not

ChatGPT stores your conversation history and, if you use Projects, some project-level instructions. That data is visible inside ChatGPT and is not accessible to Claude Code. Claude Code keeps its own conversation history and, optionally, a Claude Project with shared instructions. Those are not accessible to ChatGPT.

Neither tool stores your actual codebase — that lives in your repository. Both tools can read files when you paste them into a conversation or, in the case of Claude Code, directly from the filesystem. The code itself is the shared truth; the AI-held context is supplementary.

This asymmetry is what makes an external project record useful. Decisions made in a ChatGPT conversation are not visible to Claude Code unless you write them down somewhere both can access. That somewhere can be a file in your repository, a project instructions document, or a connected tool like fenbs that both can read through a standard connection.

How to do this with fenbs

1. Create a free account and add a project for the codebase you are working on.
2. Add your current tasks, decisions, and Where we left off for the project.
3. Connect Claude Code to fenbs at /integrations. At the start of each Claude Code session, ask it to read the project context.
4. When you switch to ChatGPT for research or review, ask it to read the same fenbs context. Decisions made in ChatGPT that affect the code go back into Decisions and rules.
5. Before switching tools, save progress so the next session starts from confirmed state rather than an assumption.