How to log in to Codex with an API key

API-key login gives Codex a local OpenAI Platform credential for private runners, remote shells, and terminal automation where browser-based ChatGPT sign-in would put a personal or workspace session on that machine. The CLI imports the key once, stores a local Codex login, and later starts can use the cached API-key profile without leaving the raw key in the shell environment.

OpenAI Codex supports ChatGPT sign-in for subscription access and API-key sign-in for usage-based access. Plain codex login starts the default ChatGPT browser path when no valid session exists, while codex login --with-api-key reads a Platform API key from standard input. The CLI and IDE extension share cached local login details.

API-key usage is billed through the OpenAI Platform account at standard API rates, follows the API organization's retention and data-sharing settings, and does not use included ChatGPT plan credits. Features that rely on ChatGPT workspace access or cloud services can be limited or unavailable with API-key authentication, and Codex cloud still requires ChatGPT sign-in. If the CLI stores credentials in auth.json under CODEX_HOME instead of an operating-system credential store, treat that file like password material.

Steps to log in to Codex with an API key:

Check the current Codex login state in the same shell that will store the new API-key session.
```
$ codex login status
Not logged in
```
If the output shows an unexpected account or sign-in method, log out before loading the new API key.
Related: How to log out of Codex
Create or copy a secret API key from the OpenAI dashboard.
```
https://platform.openai.com/api-keys
```
Treat the key like a password and keep it out of tickets, screenshots, logs, and committed files.

Tool: Secret Pattern Sample Checker
Load the secret into the current shell as OPENAI_API_KEY.
```
$ export OPENAI_API_KEY="sk-proj-REPLACE_WITH_REAL_KEY"
```
A literal export can be saved in shell history, so use a protected secret-loading method on shared systems. CODEX_API_KEY is a separate inline credential path for single codex exec runs, not the persistent login input.
Pipe the API key to Codex and let the CLI cache the local login.
```
$ printenv OPENAI_API_KEY | codex login --with-api-key
Reading API key from stdin...
Successfully logged in
```
--with-api-key reads the secret from stdin. If OPENAI_API_KEY is unset or was not exported, the command reports that no API key was provided.
Confirm the cached profile shows API-key authentication.
```
$ codex login status
Logged in using an API key - sk-proj-***ABCD1
```
The masked suffix will differ for each key. Look for an API-key authentication line before starting the Codex session or automation that depends on this login.
Remove the key from the current shell if it was loaded only for the login command.
```
$ unset OPENAI_API_KEY
```
Unsetting the environment variable does not log Codex out because the CLI already cached the authenticated session locally.