Zeltro › Codex in Zeltro: build apps with your ChatGPT plan, on your own computer

Codex in Zeltro

How Zeltro runs OpenAI's Codex: sign in with your ChatGPT plan or an OpenAI API key, or point it at Ollama or LM Studio. Zeltro installs it and hands it a project that's ready to run.

Codex is OpenAI's coding agent. It reads your project, edits the files and runs commands. In Zeltro it works inside a project that's already set up, on your own computer, with the ChatGPT plan you already pay for.

Connect it with

Your planSign in with ChatGPT
An API keyOpenAI · a server with OpenAI’s Responses API
A model on your computerOllama or LM Studio
Codex OpenAI codex Zeltro installs it developers.openai.com/codex
Your project in Zeltro
  • Runtime and database ready
  • AGENTS.md to read
  • Live preview
  • Tells the app when it’s done

What Zeltro does for Codex#

  1. Installs it

    Choose Codex when Zeltro first opens, or later in Settings → AI Profiles. Zeltro installs it on Linux, macOS or Windows (inside WSL).

  2. Connects it

    Sign in with your ChatGPT plan, or give it an OpenAI API key. Zeltro does the sign-in for you the first time you start a project.

  3. Hands it a ready project

    Every project already has its runtime, its database and a working .env, plus an AGENTS.md that tells the agent the project's address, database and commands.

  4. Runs it beside your app

    Codex works in a real terminal next to the live preview. Write long requests in the message box, and the app tells you when a turn is done or Codex needs an answer.

Your plan or a key#

Your ChatGPT plan. Choose "Sign in with my ChatGPT plan" and Codex uses the subscription you already pay for. Zeltro adds no credits and no markup.

An API key. Pay as you go with an OpenAI key (one that starts with sk-). Codex can also use another server, but only one that speaks OpenAI's Responses API, which not every OpenAI-compatible server does.

How do you want to connect Codex?

Sign in with my ChatGPT planUses the plan you already pay for. No extra charges.
Use an API keyPay as you go: OpenAI.

Codex with an API key

Where the key is from

  • OpenAI
  • Another server (enter its address)

API key

The Zeltro app’s own setup screens when you choose Codex. The same choices are in Settings → AI Profiles later.

On a model on your own computer#

In Settings → AI Profiles, a Codex profile has one-click presets for Ollama, LM Studio and OpenRouter. Zeltro passes the address to Codex as its own openai_base_url setting on every run. From a terminal:

zeltro ai-set --agent codex --model qwen3-coder:30b \
  --api-base http://localhost:11434/v1 --api-key ollama

Because Codex only speaks the Responses API, a server that doesn't implement it won't work. For anything more involved, Codex has its own --oss mode and a [model_providers] section in ~/.codex/config.toml. For local models in general, Qwen Code or Aider is less work. See cheap and local models.

From the terminal#

The app's Settings → AI Profiles does all of this, and the same settings are one command away:

zeltro ai-set --agent codex                     # sign in with your ChatGPT plan
zeltro ai-set --agent codex --model gpt-6-sol   # pick a model

Asking before each change. By default, the AI in each project works without stopping to ask first: the Works without asking switch in the project's panel is on. Switch it off and you approve each step in Codex's terminal. Zeltro passes the choice to Codex for each run (--dangerously-bypass-approvals-and-sandbox), so Codex's own settings stay as they are. To change Codex's own setting for every run, outside Zeltro too, run zeltro ai-unattended, which writes approval_policy = "never" into ~/.codex/config.toml.

Questions

Can I use my ChatGPT subscription for coding in Zeltro?

Yes. Choose "Sign in with my ChatGPT plan" and Codex uses the plan you already pay for. Zeltro sells no AI and adds nothing on top.

Do I need to install Codex first?

No. Choose it in Zeltro and Zeltro installs it, on Linux, macOS or Windows.

Can Codex run on Ollama?

Yes, through the Ollama preset in the profile, as long as the model server speaks OpenAI's Responses API. If it doesn't, Qwen Code or Aider is the simpler local choice.

Does Zeltro see my code or my prompts?

No. Codex talks straight to OpenAI, or to the server you chose. Zeltro never sees your key, your prompts or your code.

Build with Codex on your own computer

Install Zeltro, choose Codex, and sign in with the ChatGPT plan you already have. Free for personal use, with no account.

Install Zeltro Why bring your own key

Rather not set it up yourself? I’ll do it for you.

Checked 2026-11-09. Other products change often — if something here is out of date, tell us and it gets fixed.