Codex Desktop Setup

The OpenAI Codex desktop app can sign in with an API key and open the user-level config.toml from inside the app. With Aiberm configured, Codex sends requests through Aiberm’s Responses-compatible endpoint.

Prerequisites

Before you begin, make sure you have:

• The latest OpenAI Codex desktop app
• An Aiberm account (Sign up)
• An Aiberm API key (Create one in Console)

Configuration

1. Open the Codex desktop app.
2. On the sign-in screen, choose Sign in another way.

3. Enter your Aiberm API key in the OpenAI API key field, then choose Continue.

4. After entering the app, open Settings.
5. Select Configuration in the sidebar.
6. Under Custom config.toml settings, make sure User config is selected.
7. Choose Open config.toml to open the user-level config file.

8. Add or replace the contents of config.toml with:

model = "gpt-5.5"
model_provider = "aiberm"

[model_providers.aiberm]
name = "Aiberm API"
base_url = "https://aiberm.com/v1"
wire_api = "responses"

9. Save config.toml.
10. Fully quit and reopen the Codex desktop app.

Verify It Works

After reopening Codex:

1. Open a project or workspace.
2. Ask Codex to perform a real coding task, such as explaining the current file, editing a small piece of code, or running project tests.

If the task runs and returns a result, the configuration is working.

Troubleshooting

Invalid API Key

• Copy the full key from Aiberm Console.
• Check for extra spaces before or after the key.
• Confirm the key starts with sk-.

Configuration Changes Do Not Apply

• Confirm you edited the config.toml opened from User config.
• Fully quit and reopen the Codex desktop app after saving the file.
• Confirm model_provider = "aiberm" matches [model_providers.aiberm].

Model or Connection Errors

• Confirm the base_url is exactly https://aiberm.com/v1.
• Confirm wire_api is responses.
• Confirm your account can access gpt-5.5. For the current list, see Models List.

Official Reference

• OpenAI Codex: Configuration Reference