Use onomeo in Codex

What to fill in

No key yet? Create one on the My account page, then come back — the fields below fill in by themselves. Go to My account

Step by step

1. 1

   Install Codex

   On Windows, press the Windows key, type PowerShell and press Enter. On macOS, open Terminal. Paste the line below and press Enter.

   Copy

   npm install -g @openai/codex

   If npm is not found, install Node.js (the LTS version) from nodejs.org first, then close PowerShell and open it again.

2. 2

   Write the configuration

   Press Copy, paste into the same window and press Enter. The command writes this site's address, your key and the model auto into Codex's configuration file.

   WindowsmacOS / Linux

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   $f = "$HOME\.codex\config.toml"
   if (-not (Test-Path $f)) {
   New-Item -ItemType Directory -Force -Path (Split-Path $f) | Out-Null
   [IO.File]::WriteAllText($f, @'
   model_provider = "onomeo"
   model = "auto"
   
   [model_providers.onomeo]
   name = "onomeo"
   base_url = "https://onomeo.com/v1"
   wire_api = "responses"
   experimental_bearer_token = "YOUR_API_KEY"
   '@)
   Write-Host "Saved: $f" -ForegroundColor Green
   } else { Write-Host "A configuration file already exists, left unchanged: $f" -ForegroundColor Yellow }

   Replace YOUR_API_KEY in the command with your key. Once you create a key in this browser, it is filled in here.

   A green "Saved" on the last line means the configuration is in. A yellow "already exists" means Codex was set up before: open the file it names in a text editor and add the contents of the box above at the end (the model_provider and model lines at the top replace the two lines of the same name already there).

3. 3

   Start Codex

   Go to your project folder first (for example, type cd D:\my-project and press Enter), then run the line below. The first start asks whether you trust the folder (Do you trust the contents of this directory?): press Enter for Yes, continue.

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   codex

4. 4

   Choose the sandbox

   It then asks about the sandbox (Set up the Codex agent sandbox): press the down arrow key once to reach Use non-admin sandbox, then Enter; no administrator rights are needed. The box above now reads model: auto, which means the configuration is in use.

   

   If PowerShell is running as administrator, the first choice is safer.

5. 5

   Give it a task

   Type what you want done and press Enter. Before writing a file or running a command, Codex asks Would you like to run the following command?: press Enter for Yes, proceed.

   

   The line "Model metadata for auto not found" that appears after the first message is Codex noting it does not know the name auto; it does not affect anything.

6. 6

   See the result

   Once the commands have run, Codex reports the result, and the bottom line shows the model it used, auto.

   

   Each step counts as 1 call, and a long step counts as several. Measured on 9 October 2026 with Codex 0.153.4: the task above took 4 calls on auto and was not charged.

If it will not connect

• Keep /v1 at the end of the address and add nothing after it. wire_api must be responses; newer Codex no longer supports chat.
• To use another model from the Models page, change the line model = "auto" in the configuration file and start Codex again.
• Coding sends whole files along with each request. On free models that is not charged, but a long request counts as several calls; Claude, GPT and other big models are charged by usage, and the balance goes quickly.
• An answer that reads "onomeo could not run this request (bad_key)": the key is wrong; correct the experimental_bearer_token line in the configuration file. With not_enough_credit in the brackets: insufficient balance. Claude, GPT and other big models are charged by usage; top up on the Pricing page or switch to a free model.
• Once your own provider keys are connected on the My providers page, change the model line to my/<provider>/<model> to answer on your own allowance instead. Nothing else changes, and this site does not charge for these calls.