3.1 Codex

Applies to the Codex CLI, Codex VSCode extension, and Codex mobile app. All three share the same API configuration; only the place where you enter it differs.

Prepare two things

Setting	Value
Base URL	https://axiomcode.top/v1
API Key	sk-axiom-xxxx (from 2.2 Create a Key)

System requirements

Form factor	Requirements
Codex CLI	Node.js 18+; Windows 10/11 · macOS · Linux (incl. WSL)
VSCode plugin	Latest VS Code + the Codex extension
Mobile app	iOS / Android, from the app store

Method 1: Environment variables (fastest)

Set the address and key as environment variables (pick your OS):

macOS / Linux

# Append to ~/.zshrc or ~/.bashrc, then run source to apply
export OPENAI_API_KEY="sk-axiom-your-key"
export OPENAI_BASE_URL="https://axiomcode.top/v1"

Windows PowerShell

# Persist to user environment variables; takes effect after reopening the terminal
[Environment]::SetEnvironmentVariable("OPENAI_API_KEY", "sk-axiom-your-key", "User")
[Environment]::SetEnvironmentVariable("OPENAI_BASE_URL", "https://axiomcode.top/v1", "User")

Method 2: Config file

Config file location:

• macOS / Linux: ~/.codex/config.toml
• Windows: C:\Users\<username>\.codex\config.toml

[provider.axiom]
base_url = "https://axiomcode.top/v1"
api_key = "sk-axiom-your-key"

[default]
provider = "axiom"
model = "gpt-5-codex"

Verify

Run in the terminal:

codex --version
codex chat "Introduce quicksort in one sentence"

If it returns a normal response, the connection is working.

Codex VSCode extension

1. Search for and install "Codex" in the VSCode extension marketplace.
2. Open Settings (Ctrl/⌘ + ,) and search for codex.
3. Fill in two fields:
   • Codex: Api Base Url → https://axiomcode.top/v1
   • Codex: Api Key → sk-axiom-your-key
4. Press Ctrl/⌘ + Shift + P, type Codex: Reload, or restart VSCode.
5. Open any file and press the default shortcut Ctrl/⌘ + I to test.

Codex mobile app

1. Search for and install the "Codex" app from the app store.
2. Go to Settings → API Access.
3. Fill in:
   • API URL: https://axiomcode.top/v1
   • API Key: sk-axiom-your-key
4. Save and start a new conversation to test.

Recommendation

Generate a dedicated Key for the mobile app. If the device is lost, you only need to disable this Key, without affecting other Keys on your computer or server.

FAQ

Question	Notes
Which model should I pick?	gpt-5-codex is the default recommendation; see the Key's "Access Configuration" dialog for available models
Returns 401	99% of the time the Key is wrong (extra space, missing sk- prefix) — check it on the Key management page
Returns 404 / model not found	The Base URL is wrong (missing /v1 or has an extra path), or the model is not available for your account

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Next: 3.2 Claude Code